linux/drivers/spi/spi-bcm2835.c

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spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/*
* Driver for Broadcom BCM2835 SPI Controllers
*
* Copyright (C) 2012 Chris Boot
* Copyright (C) 2013 Stephen Warren
* Copyright (C) 2015 Martin Sperl
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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*
* This driver is inspired by:
* spi-ath79.c, Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
* spi-atmel.c, Copyright (C) 2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <asm/page.h>
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/of_irq.h>
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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#include <linux/spi/spi.h>
/* SPI register offsets */
#define BCM2835_SPI_CS 0x00
#define BCM2835_SPI_FIFO 0x04
#define BCM2835_SPI_CLK 0x08
#define BCM2835_SPI_DLEN 0x0c
#define BCM2835_SPI_LTOH 0x10
#define BCM2835_SPI_DC 0x14
/* Bitfields in CS */
#define BCM2835_SPI_CS_LEN_LONG 0x02000000
#define BCM2835_SPI_CS_DMA_LEN 0x01000000
#define BCM2835_SPI_CS_CSPOL2 0x00800000
#define BCM2835_SPI_CS_CSPOL1 0x00400000
#define BCM2835_SPI_CS_CSPOL0 0x00200000
#define BCM2835_SPI_CS_RXF 0x00100000
#define BCM2835_SPI_CS_RXR 0x00080000
#define BCM2835_SPI_CS_TXD 0x00040000
#define BCM2835_SPI_CS_RXD 0x00020000
#define BCM2835_SPI_CS_DONE 0x00010000
#define BCM2835_SPI_CS_LEN 0x00002000
#define BCM2835_SPI_CS_REN 0x00001000
#define BCM2835_SPI_CS_ADCS 0x00000800
#define BCM2835_SPI_CS_INTR 0x00000400
#define BCM2835_SPI_CS_INTD 0x00000200
#define BCM2835_SPI_CS_DMAEN 0x00000100
#define BCM2835_SPI_CS_TA 0x00000080
#define BCM2835_SPI_CS_CSPOL 0x00000040
#define BCM2835_SPI_CS_CLEAR_RX 0x00000020
#define BCM2835_SPI_CS_CLEAR_TX 0x00000010
#define BCM2835_SPI_CS_CPOL 0x00000008
#define BCM2835_SPI_CS_CPHA 0x00000004
#define BCM2835_SPI_CS_CS_10 0x00000002
#define BCM2835_SPI_CS_CS_01 0x00000001
#define BCM2835_SPI_POLLING_LIMIT_US 30
#define BCM2835_SPI_POLLING_JIFFIES 2
#define BCM2835_SPI_DMA_MIN_LENGTH 96
#define BCM2835_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \
| SPI_NO_CS | SPI_3WIRE)
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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#define DRV_NAME "spi-bcm2835"
struct bcm2835_spi {
void __iomem *regs;
struct clk *clk;
int irq;
const u8 *tx_buf;
u8 *rx_buf;
int tx_len;
int rx_len;
bool dma_pending;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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};
static inline u32 bcm2835_rd(struct bcm2835_spi *bs, unsigned reg)
{
return readl(bs->regs + reg);
}
static inline void bcm2835_wr(struct bcm2835_spi *bs, unsigned reg, u32 val)
{
writel(val, bs->regs + reg);
}
static inline void bcm2835_rd_fifo(struct bcm2835_spi *bs)
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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{
u8 byte;
while ((bs->rx_len) &&
(bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_RXD)) {
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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byte = bcm2835_rd(bs, BCM2835_SPI_FIFO);
if (bs->rx_buf)
*bs->rx_buf++ = byte;
bs->rx_len--;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
}
static inline void bcm2835_wr_fifo(struct bcm2835_spi *bs)
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
{
u8 byte;
while ((bs->tx_len) &&
(bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_TXD)) {
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
byte = bs->tx_buf ? *bs->tx_buf++ : 0;
bcm2835_wr(bs, BCM2835_SPI_FIFO, byte);
bs->tx_len--;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
}
static void bcm2835_spi_reset_hw(struct spi_master *master)
{
struct bcm2835_spi *bs = spi_master_get_devdata(master);
u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
/* Disable SPI interrupts and transfer */
cs &= ~(BCM2835_SPI_CS_INTR |
BCM2835_SPI_CS_INTD |
BCM2835_SPI_CS_DMAEN |
BCM2835_SPI_CS_TA);
/* and reset RX/TX FIFOS */
cs |= BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX;
/* and reset the SPI_HW */
bcm2835_wr(bs, BCM2835_SPI_CS, cs);
/* as well as DLEN */
bcm2835_wr(bs, BCM2835_SPI_DLEN, 0);
}
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id)
{
struct spi_master *master = dev_id;
struct bcm2835_spi *bs = spi_master_get_devdata(master);
/* Read as many bytes as possible from FIFO */
bcm2835_rd_fifo(bs);
/* Write as many bytes as possible to FIFO */
bcm2835_wr_fifo(bs);
/* based on flags decide if we can finish the transfer */
if (bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_DONE) {
/* Transfer complete - reset SPI HW */
bcm2835_spi_reset_hw(master);
/* wake up the framework */
complete(&master->xfer_completion);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
return IRQ_HANDLED;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
static int bcm2835_spi_transfer_one_irq(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *tfr,
u32 cs)
{
struct bcm2835_spi *bs = spi_master_get_devdata(master);
/* fill in fifo if we have gpio-cs
* note that there have been rare events where the native-CS
* flapped for <1us which may change the behaviour
* with gpio-cs this does not happen, so it is implemented
* only for this case
*/
if (gpio_is_valid(spi->cs_gpio)) {
/* enable HW block, but without interrupts enabled
* this would triggern an immediate interrupt
*/
bcm2835_wr(bs, BCM2835_SPI_CS,
cs | BCM2835_SPI_CS_TA);
/* fill in tx fifo as much as possible */
bcm2835_wr_fifo(bs);
}
/*
* Enable the HW block. This will immediately trigger a DONE (TX
* empty) interrupt, upon which we will fill the TX FIFO with the
* first TX bytes. Pre-filling the TX FIFO here to avoid the
* interrupt doesn't work:-(
*/
cs |= BCM2835_SPI_CS_INTR | BCM2835_SPI_CS_INTD | BCM2835_SPI_CS_TA;
bcm2835_wr(bs, BCM2835_SPI_CS, cs);
/* signal that we need to wait for completion */
return 1;
}
/*
* DMA support
*
* this implementation has currently a few issues in so far as it does
* not work arrount limitations of the HW.
*
* the main one being that DMA transfers are limited to 16 bit
* (so 0 to 65535 bytes) by the SPI HW due to BCM2835_SPI_DLEN
*
* also we currently assume that the scatter-gather fragments are
* all multiple of 4 (except the last) - otherwise we would need
* to reset the FIFO before subsequent transfers...
* this also means that tx/rx transfers sg's need to be of equal size!
*
* there may be a few more border-cases we may need to address as well
* but unfortunately this would mean splitting up the scatter-gather
* list making it slightly unpractical...
*/
static void bcm2835_spi_dma_done(void *data)
{
struct spi_master *master = data;
struct bcm2835_spi *bs = spi_master_get_devdata(master);
/* reset fifo and HW */
bcm2835_spi_reset_hw(master);
/* and terminate tx-dma as we do not have an irq for it
* because when the rx dma will terminate and this callback
* is called the tx-dma must have finished - can't get to this
* situation otherwise...
*/
dmaengine_terminate_all(master->dma_tx);
/* mark as no longer pending */
bs->dma_pending = 0;
/* and mark as completed */;
complete(&master->xfer_completion);
}
static int bcm2835_spi_prepare_sg(struct spi_master *master,
struct spi_transfer *tfr,
bool is_tx)
{
struct dma_chan *chan;
struct scatterlist *sgl;
unsigned int nents;
enum dma_transfer_direction dir;
unsigned long flags;
struct dma_async_tx_descriptor *desc;
dma_cookie_t cookie;
if (is_tx) {
dir = DMA_MEM_TO_DEV;
chan = master->dma_tx;
nents = tfr->tx_sg.nents;
sgl = tfr->tx_sg.sgl;
flags = 0 /* no tx interrupt */;
} else {
dir = DMA_DEV_TO_MEM;
chan = master->dma_rx;
nents = tfr->rx_sg.nents;
sgl = tfr->rx_sg.sgl;
flags = DMA_PREP_INTERRUPT;
}
/* prepare the channel */
desc = dmaengine_prep_slave_sg(chan, sgl, nents, dir, flags);
if (!desc)
return -EINVAL;
/* set callback for rx */
if (!is_tx) {
desc->callback = bcm2835_spi_dma_done;
desc->callback_param = master;
}
/* submit it to DMA-engine */
cookie = dmaengine_submit(desc);
return dma_submit_error(cookie);
}
static inline int bcm2835_check_sg_length(struct sg_table *sgt)
{
int i;
struct scatterlist *sgl;
/* check that the sg entries are word-sized (except for last) */
for_each_sg(sgt->sgl, sgl, (int)sgt->nents - 1, i) {
if (sg_dma_len(sgl) % 4)
return -EFAULT;
}
return 0;
}
static int bcm2835_spi_transfer_one_dma(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *tfr,
u32 cs)
{
struct bcm2835_spi *bs = spi_master_get_devdata(master);
int ret;
/* check that the scatter gather segments are all a multiple of 4 */
if (bcm2835_check_sg_length(&tfr->tx_sg) ||
bcm2835_check_sg_length(&tfr->rx_sg)) {
dev_warn_once(&spi->dev,
"scatter gather segment length is not a multiple of 4 - falling back to interrupt mode\n");
return bcm2835_spi_transfer_one_irq(master, spi, tfr, cs);
}
/* setup tx-DMA */
ret = bcm2835_spi_prepare_sg(master, tfr, true);
if (ret)
return ret;
/* start TX early */
dma_async_issue_pending(master->dma_tx);
/* mark as dma pending */
bs->dma_pending = 1;
/* set the DMA length */
bcm2835_wr(bs, BCM2835_SPI_DLEN, tfr->len);
/* start the HW */
bcm2835_wr(bs, BCM2835_SPI_CS,
cs | BCM2835_SPI_CS_TA | BCM2835_SPI_CS_DMAEN);
/* setup rx-DMA late - to run transfers while
* mapping of the rx buffers still takes place
* this saves 10us or more.
*/
ret = bcm2835_spi_prepare_sg(master, tfr, false);
if (ret) {
/* need to reset on errors */
dmaengine_terminate_all(master->dma_tx);
bcm2835_spi_reset_hw(master);
return ret;
}
/* start rx dma late */
dma_async_issue_pending(master->dma_rx);
/* wait for wakeup in framework */
return 1;
}
static bool bcm2835_spi_can_dma(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *tfr)
{
/* only run for gpio_cs */
if (!gpio_is_valid(spi->cs_gpio))
return false;
/* we start DMA efforts only on bigger transfers */
if (tfr->len < BCM2835_SPI_DMA_MIN_LENGTH)
return false;
/* BCM2835_SPI_DLEN has defined a max transfer size as
* 16 bit, so max is 65535
* we can revisit this by using an alternative transfer
* method - ideally this would get done without any more
* interaction...
*/
if (tfr->len > 65535) {
dev_warn_once(&spi->dev,
"transfer size of %d too big for dma-transfer\n",
tfr->len);
return false;
}
/* if we run rx/tx_buf with word aligned addresses then we are OK */
if ((((size_t)tfr->rx_buf & 3) == 0) &&
(((size_t)tfr->tx_buf & 3) == 0))
return true;
/* otherwise we only allow transfers within the same page
* to avoid wasting time on dma_mapping when it is not practical
*/
if (((size_t)tfr->tx_buf & (PAGE_SIZE - 1)) + tfr->len > PAGE_SIZE) {
dev_warn_once(&spi->dev,
"Unaligned spi tx-transfer bridging page\n");
return false;
}
if (((size_t)tfr->rx_buf & (PAGE_SIZE - 1)) + tfr->len > PAGE_SIZE) {
dev_warn_once(&spi->dev,
"Unaligned spi rx-transfer bridging page\n");
return false;
}
/* return OK */
return true;
}
static void bcm2835_dma_release(struct spi_master *master)
{
if (master->dma_tx) {
dmaengine_terminate_all(master->dma_tx);
dma_release_channel(master->dma_tx);
master->dma_tx = NULL;
}
if (master->dma_rx) {
dmaengine_terminate_all(master->dma_rx);
dma_release_channel(master->dma_rx);
master->dma_rx = NULL;
}
}
static void bcm2835_dma_init(struct spi_master *master, struct device *dev)
{
struct dma_slave_config slave_config;
const __be32 *addr;
dma_addr_t dma_reg_base;
int ret;
/* base address in dma-space */
addr = of_get_address(master->dev.of_node, 0, NULL, NULL);
if (!addr) {
dev_err(dev, "could not get DMA-register address - not using dma mode\n");
goto err;
}
dma_reg_base = be32_to_cpup(addr);
/* get tx/rx dma */
master->dma_tx = dma_request_slave_channel(dev, "tx");
if (!master->dma_tx) {
dev_err(dev, "no tx-dma configuration found - not using dma mode\n");
goto err;
}
master->dma_rx = dma_request_slave_channel(dev, "rx");
if (!master->dma_rx) {
dev_err(dev, "no rx-dma configuration found - not using dma mode\n");
goto err_release;
}
/* configure DMAs */
slave_config.direction = DMA_MEM_TO_DEV;
slave_config.dst_addr = (u32)(dma_reg_base + BCM2835_SPI_FIFO);
slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
ret = dmaengine_slave_config(master->dma_tx, &slave_config);
if (ret)
goto err_config;
slave_config.direction = DMA_DEV_TO_MEM;
slave_config.src_addr = (u32)(dma_reg_base + BCM2835_SPI_FIFO);
slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
ret = dmaengine_slave_config(master->dma_rx, &slave_config);
if (ret)
goto err_config;
/* all went well, so set can_dma */
master->can_dma = bcm2835_spi_can_dma;
master->max_dma_len = 65535; /* limitation by BCM2835_SPI_DLEN */
/* need to do TX AND RX DMA, so we need dummy buffers */
master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
return;
err_config:
dev_err(dev, "issue configuring dma: %d - not using DMA mode\n",
ret);
err_release:
bcm2835_dma_release(master);
err:
return;
}
static int bcm2835_spi_transfer_one_poll(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *tfr,
u32 cs,
unsigned long long xfer_time_us)
{
struct bcm2835_spi *bs = spi_master_get_devdata(master);
unsigned long timeout;
/* enable HW block without interrupts */
bcm2835_wr(bs, BCM2835_SPI_CS, cs | BCM2835_SPI_CS_TA);
/* fill in the fifo before timeout calculations
* if we are interrupted here, then the data is
* getting transferred by the HW while we are interrupted
*/
bcm2835_wr_fifo(bs);
/* set the timeout */
timeout = jiffies + BCM2835_SPI_POLLING_JIFFIES;
/* loop until finished the transfer */
while (bs->rx_len) {
/* fill in tx fifo with remaining data */
bcm2835_wr_fifo(bs);
/* read from fifo as much as possible */
bcm2835_rd_fifo(bs);
/* if there is still data pending to read
* then check the timeout
*/
if (bs->rx_len && time_after(jiffies, timeout)) {
dev_dbg_ratelimited(&spi->dev,
"timeout period reached: jiffies: %lu remaining tx/rx: %d/%d - falling back to interrupt mode\n",
jiffies - timeout,
bs->tx_len, bs->rx_len);
/* fall back to interrupt mode */
return bcm2835_spi_transfer_one_irq(master, spi,
tfr, cs);
}
}
/* Transfer complete - reset SPI HW */
bcm2835_spi_reset_hw(master);
/* and return without waiting for completion */
return 0;
}
static int bcm2835_spi_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *tfr)
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
{
struct bcm2835_spi *bs = spi_master_get_devdata(master);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
unsigned long spi_hz, clk_hz, cdiv;
unsigned long spi_used_hz;
unsigned long long xfer_time_us;
u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* set clock */
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
spi_hz = tfr->speed_hz;
clk_hz = clk_get_rate(bs->clk);
if (spi_hz >= clk_hz / 2) {
cdiv = 2; /* clk_hz/2 is the fastest we can go */
} else if (spi_hz) {
/* CDIV must be a multiple of two */
cdiv = DIV_ROUND_UP(clk_hz, spi_hz);
cdiv += (cdiv % 2);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
if (cdiv >= 65536)
cdiv = 0; /* 0 is the slowest we can go */
} else {
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
cdiv = 0; /* 0 is the slowest we can go */
}
spi_used_hz = cdiv ? (clk_hz / cdiv) : (clk_hz / 65536);
bcm2835_wr(bs, BCM2835_SPI_CLK, cdiv);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* handle all the 3-wire mode */
if ((spi->mode & SPI_3WIRE) && (tfr->rx_buf))
cs |= BCM2835_SPI_CS_REN;
else
cs &= ~BCM2835_SPI_CS_REN;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* for gpio_cs set dummy CS so that no HW-CS get changed
* we can not run this in bcm2835_spi_set_cs, as it does
* not get called for cs_gpio cases, so we need to do it here
*/
if (gpio_is_valid(spi->cs_gpio) || (spi->mode & SPI_NO_CS))
cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* set transmit buffers and length */
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
bs->tx_buf = tfr->tx_buf;
bs->rx_buf = tfr->rx_buf;
bs->tx_len = tfr->len;
bs->rx_len = tfr->len;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* calculate the estimated time in us the transfer runs */
xfer_time_us = (unsigned long long)tfr->len
* 9 /* clocks/byte - SPI-HW waits 1 clock after each byte */
* 1000000;
do_div(xfer_time_us, spi_used_hz);
/* for short requests run polling*/
if (xfer_time_us <= BCM2835_SPI_POLLING_LIMIT_US)
return bcm2835_spi_transfer_one_poll(master, spi, tfr,
cs, xfer_time_us);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* run in dma mode if conditions are right */
if (master->can_dma && bcm2835_spi_can_dma(master, spi, tfr))
return bcm2835_spi_transfer_one_dma(master, spi, tfr, cs);
/* run in interrupt-mode */
return bcm2835_spi_transfer_one_irq(master, spi, tfr, cs);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
static int bcm2835_spi_prepare_message(struct spi_master *master,
struct spi_message *msg)
{
struct spi_device *spi = msg->spi;
struct bcm2835_spi *bs = spi_master_get_devdata(master);
u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
cs &= ~(BCM2835_SPI_CS_CPOL | BCM2835_SPI_CS_CPHA);
if (spi->mode & SPI_CPOL)
cs |= BCM2835_SPI_CS_CPOL;
if (spi->mode & SPI_CPHA)
cs |= BCM2835_SPI_CS_CPHA;
bcm2835_wr(bs, BCM2835_SPI_CS, cs);
return 0;
}
static void bcm2835_spi_handle_err(struct spi_master *master,
struct spi_message *msg)
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
{
struct bcm2835_spi *bs = spi_master_get_devdata(master);
/* if an error occurred and we have an active dma, then terminate */
if (bs->dma_pending) {
dmaengine_terminate_all(master->dma_tx);
dmaengine_terminate_all(master->dma_rx);
bs->dma_pending = 0;
}
/* and reset */
bcm2835_spi_reset_hw(master);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
static void bcm2835_spi_set_cs(struct spi_device *spi, bool gpio_level)
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
{
/*
* we can assume that we are "native" as per spi_set_cs
* calling us ONLY when cs_gpio is not set
* we can also assume that we are CS < 3 as per bcm2835_spi_setup
* we would not get called because of error handling there.
* the level passed is the electrical level not enabled/disabled
* so it has to get translated back to enable/disable
* see spi_set_cs in spi.c for the implementation
*/
struct spi_master *master = spi->master;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
struct bcm2835_spi *bs = spi_master_get_devdata(master);
u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
bool enable;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* calculate the enable flag from the passed gpio_level */
enable = (spi->mode & SPI_CS_HIGH) ? gpio_level : !gpio_level;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* set flags for "reverse" polarity in the registers */
if (spi->mode & SPI_CS_HIGH) {
/* set the correct CS-bits */
cs |= BCM2835_SPI_CS_CSPOL;
cs |= BCM2835_SPI_CS_CSPOL0 << spi->chip_select;
} else {
/* clean the CS-bits */
cs &= ~BCM2835_SPI_CS_CSPOL;
cs &= ~(BCM2835_SPI_CS_CSPOL0 << spi->chip_select);
}
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
/* select the correct chip_select depending on disabled/enabled */
if (enable) {
/* set cs correctly */
if (spi->mode & SPI_NO_CS) {
/* use the "undefined" chip-select */
cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
} else {
/* set the chip select */
cs &= ~(BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01);
cs |= spi->chip_select;
}
} else {
/* disable CSPOL which puts HW-CS into deselected state */
cs &= ~BCM2835_SPI_CS_CSPOL;
/* use the "undefined" chip-select as precaution */
cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
/* finally set the calculated flags in SPI_CS */
bcm2835_wr(bs, BCM2835_SPI_CS, cs);
}
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
static int chip_match_name(struct gpio_chip *chip, void *data)
{
return !strcmp(chip->label, data);
}
static int bcm2835_spi_setup(struct spi_device *spi)
{
int err;
struct gpio_chip *chip;
/*
* sanity checking the native-chipselects
*/
if (spi->mode & SPI_NO_CS)
return 0;
if (gpio_is_valid(spi->cs_gpio))
return 0;
if (spi->chip_select > 1) {
/* error in the case of native CS requested with CS > 1
* officially there is a CS2, but it is not documented
* which GPIO is connected with that...
*/
dev_err(&spi->dev,
"setup: only two native chip-selects are supported\n");
return -EINVAL;
}
/* now translate native cs to GPIO */
/* get the gpio chip for the base */
chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
if (!chip)
return 0;
/* and calculate the real CS */
spi->cs_gpio = chip->base + 8 - spi->chip_select;
/* and set up the "mode" and level */
dev_info(&spi->dev, "setting up native-CS%i as GPIO %i\n",
spi->chip_select, spi->cs_gpio);
/* set up GPIO as output and pull to the correct level */
err = gpio_direction_output(spi->cs_gpio,
(spi->mode & SPI_CS_HIGH) ? 0 : 1);
if (err) {
dev_err(&spi->dev,
"could not set CS%i gpio %i as output: %i",
spi->chip_select, spi->cs_gpio, err);
return err;
}
return 0;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
static int bcm2835_spi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct bcm2835_spi *bs;
struct resource *res;
int err;
master = spi_alloc_master(&pdev->dev, sizeof(*bs));
if (!master) {
dev_err(&pdev->dev, "spi_alloc_master() failed\n");
return -ENOMEM;
}
platform_set_drvdata(pdev, master);
master->mode_bits = BCM2835_SPI_MODE_BITS;
master->bits_per_word_mask = SPI_BPW_MASK(8);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
master->num_chipselect = 3;
master->setup = bcm2835_spi_setup;
master->set_cs = bcm2835_spi_set_cs;
master->transfer_one = bcm2835_spi_transfer_one;
master->handle_err = bcm2835_spi_handle_err;
master->prepare_message = bcm2835_spi_prepare_message;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
master->dev.of_node = pdev->dev.of_node;
bs = spi_master_get_devdata(master);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
bs->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(bs->regs)) {
err = PTR_ERR(bs->regs);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
goto out_master_put;
}
bs->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(bs->clk)) {
err = PTR_ERR(bs->clk);
dev_err(&pdev->dev, "could not get clk: %d\n", err);
goto out_master_put;
}
bs->irq = platform_get_irq(pdev, 0);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
if (bs->irq <= 0) {
dev_err(&pdev->dev, "could not get IRQ: %d\n", bs->irq);
err = bs->irq ? bs->irq : -ENODEV;
goto out_master_put;
}
clk_prepare_enable(bs->clk);
bcm2835_dma_init(master, &pdev->dev);
/* initialise the hardware with the default polarities */
bcm2835_wr(bs, BCM2835_SPI_CS,
BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX);
err = devm_request_irq(&pdev->dev, bs->irq, bcm2835_spi_interrupt, 0,
dev_name(&pdev->dev), master);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
if (err) {
dev_err(&pdev->dev, "could not request IRQ: %d\n", err);
goto out_clk_disable;
}
err = devm_spi_register_master(&pdev->dev, master);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
if (err) {
dev_err(&pdev->dev, "could not register SPI master: %d\n", err);
goto out_clk_disable;
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
}
return 0;
out_clk_disable:
clk_disable_unprepare(bs->clk);
out_master_put:
spi_master_put(master);
return err;
}
static int bcm2835_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
struct bcm2835_spi *bs = spi_master_get_devdata(master);
/* Clear FIFOs, and disable the HW block */
bcm2835_wr(bs, BCM2835_SPI_CS,
BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX);
clk_disable_unprepare(bs->clk);
bcm2835_dma_release(master);
spi: add driver for BCM2835 The BCM2835 contains two forms of SPI master controller (one known simply as SPI0, and the other known as the "Universal SPI Master", in the auxilliary block) and one form of SPI slave controller. This patch adds support for the SPI0 controller. This driver is taken from Chris Boot's repository at git://github.com/bootc/linux.git rpi-linear as of commit 6de2905 "spi-bcm2708: fix printf with spurious %s". In the first SPI-related commit there, Chris wrote: Thanks to csoutreach / A Robinson for his driver which I used as an inspiration. You can find his version here: http://piface.openlx.org.uk/raspberry-pi-spi-kernel-driver-available-for Changes made during upstreaming: * Renamed bcm2708 to bcm2835 as per upstream naming for this SoC. * Removed support for brcm,realtime property. * Increased transfer timeout to 30 seconds. * Return IRQ_NONE from the IRQ handler if no interrupt was handled. * Disable TA (Transfer Active) and clear FIFOs on a transfer timeout. * Wrote device tree binding documentation. * Request unnamed clock rather than "sys_pclk"; the DT will provide the correct clock. * Assume that tfr->speed_hz and tfr->bits_per_word are always set in bcm2835_spi_start_transfer(), bcm2835_spi_transfer_one(), so no need to check spi->speed_hz or tft->bits_per_word. * Re-ordered probe() to remove the need for temporary variables. * Call clk_disable_unprepare() rather than just clk_unprepare() on probe() failure. * Don't use devm_request_irq(), to ensure that the IRQ doesn't fire after we've torn down the device, but not unhooked the IRQ. * Moved probe()'s call to clk_prepare_enable() so we can be sure the clock is enabled if the IRQ handler fires immediately. * Remove redundant checks from bcm2835_spi_check_transfer() and bcm2835_spi_setup(). * Re-ordered IRQ handler to check for RXR before DONE. Added comments to ISR. * Removed empty prepare/unprepare implementations. * Removed use of devinit/devexit. * Added BCM2835_ prefix to defines. Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2013-03-12 03:38:24 +00:00
return 0;
}
static const struct of_device_id bcm2835_spi_match[] = {
{ .compatible = "brcm,bcm2835-spi", },
{}
};
MODULE_DEVICE_TABLE(of, bcm2835_spi_match);
static struct platform_driver bcm2835_spi_driver = {
.driver = {
.name = DRV_NAME,
.of_match_table = bcm2835_spi_match,
},
.probe = bcm2835_spi_probe,
.remove = bcm2835_spi_remove,
};
module_platform_driver(bcm2835_spi_driver);
MODULE_DESCRIPTION("SPI controller driver for Broadcom BCM2835");
MODULE_AUTHOR("Chris Boot <bootc@bootc.net>");
MODULE_LICENSE("GPL v2");