linux/drivers/spi/spi-imx.c
Marek Vasut 6fd8b8503a spi: spi-imx: Fix out-of-order CS/SCLK operation at low speeds
Problem:
--------
 The problem this patch addresses has the following assumptions about the
 SPI bus setup:
 - The hardware used to find this is Freescale i.MX537 @ 1200MHz
 - The SPI SCLK operate at very low speed, less than 200 kHz
 - There are two SPI devices attached to the bus
   - Each device uses different GPIO for chipselect
   - Each device requires different SCLK signal polarity

 The observation of the SCLK and GPIO chipselect lines with a logic analyzer
 shows, that the SCLK polarity change does sometimes happen after the GPIO
 chipselect is asserted. The SPI slave device reacts on that by counting the
 SCLK polarity change as a clock pulse, which disrupts the communication with
 the SPI slave device.

Explanation:
------------
 We found an interesting correlation, that the maximum delay between the write
 into the ECSPIx_CONFIGREG register and the change of SCLK polarity at each
 SCLK frequency of 10 kHz, 20 kHz, 50 kHz and 100 kHz is 100 uS, 50 uS, 20 uS
 and 10 uS respectively. This lead us to a theory, that at SCLK frequency of
 1 Hz, the delay would be 1 S. Therefore, the time it takes for the write to
 ECSPIx_CONFIGREG to take effect in the hardware is up to the duration of 1
 tick of the SCLK clock.

 During this delay period, if the SCLK frequency is too low, the execution of
 the spi-imx.c driver can advance so much, that the GPIO chipselect will be
 asserted. The GPIO chipselect is asserted almost immediatelly.

Solution:
---------
 The solution this patch presents is simple. We calculate the resulting SCLK
 clock first by dividing the ECSPI block clock by both dividers that are to be
 programmed into the configuration register. Based on the resulting SCLK clock,
 we derive the delay it will take for the changes to get really applied. We are
 extra careful here so we delay twice as long as we should. Note that the patch
 does not create additional overhead at high speeds as the delay will likely be
 close to zero there.

Signed-off-by: Marek Vasut <marex@denx.de>
To: linux-spi@vger.kernel.org
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Huang Shijie <b32955@freescale.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-12-20 11:53:57 +00:00

974 lines
25 KiB
C

/*
* Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright (C) 2008 Juergen Beisert
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301, USA.
*/
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/types.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/platform_data/spi-imx.h>
#define DRIVER_NAME "spi_imx"
#define MXC_CSPIRXDATA 0x00
#define MXC_CSPITXDATA 0x04
#define MXC_CSPICTRL 0x08
#define MXC_CSPIINT 0x0c
#define MXC_RESET 0x1c
/* generic defines to abstract from the different register layouts */
#define MXC_INT_RR (1 << 0) /* Receive data ready interrupt */
#define MXC_INT_TE (1 << 1) /* Transmit FIFO empty interrupt */
struct spi_imx_config {
unsigned int speed_hz;
unsigned int bpw;
unsigned int mode;
u8 cs;
};
enum spi_imx_devtype {
IMX1_CSPI,
IMX21_CSPI,
IMX27_CSPI,
IMX31_CSPI,
IMX35_CSPI, /* CSPI on all i.mx except above */
IMX51_ECSPI, /* ECSPI on i.mx51 and later */
};
struct spi_imx_data;
struct spi_imx_devtype_data {
void (*intctrl)(struct spi_imx_data *, int);
int (*config)(struct spi_imx_data *, struct spi_imx_config *);
void (*trigger)(struct spi_imx_data *);
int (*rx_available)(struct spi_imx_data *);
void (*reset)(struct spi_imx_data *);
enum spi_imx_devtype devtype;
};
struct spi_imx_data {
struct spi_bitbang bitbang;
struct completion xfer_done;
void __iomem *base;
int irq;
struct clk *clk_per;
struct clk *clk_ipg;
unsigned long spi_clk;
unsigned int count;
void (*tx)(struct spi_imx_data *);
void (*rx)(struct spi_imx_data *);
void *rx_buf;
const void *tx_buf;
unsigned int txfifo; /* number of words pushed in tx FIFO */
const struct spi_imx_devtype_data *devtype_data;
int chipselect[0];
};
static inline int is_imx27_cspi(struct spi_imx_data *d)
{
return d->devtype_data->devtype == IMX27_CSPI;
}
static inline int is_imx35_cspi(struct spi_imx_data *d)
{
return d->devtype_data->devtype == IMX35_CSPI;
}
static inline unsigned spi_imx_get_fifosize(struct spi_imx_data *d)
{
return (d->devtype_data->devtype == IMX51_ECSPI) ? 64 : 8;
}
#define MXC_SPI_BUF_RX(type) \
static void spi_imx_buf_rx_##type(struct spi_imx_data *spi_imx) \
{ \
unsigned int val = readl(spi_imx->base + MXC_CSPIRXDATA); \
\
if (spi_imx->rx_buf) { \
*(type *)spi_imx->rx_buf = val; \
spi_imx->rx_buf += sizeof(type); \
} \
}
#define MXC_SPI_BUF_TX(type) \
static void spi_imx_buf_tx_##type(struct spi_imx_data *spi_imx) \
{ \
type val = 0; \
\
if (spi_imx->tx_buf) { \
val = *(type *)spi_imx->tx_buf; \
spi_imx->tx_buf += sizeof(type); \
} \
\
spi_imx->count -= sizeof(type); \
\
writel(val, spi_imx->base + MXC_CSPITXDATA); \
}
MXC_SPI_BUF_RX(u8)
MXC_SPI_BUF_TX(u8)
MXC_SPI_BUF_RX(u16)
MXC_SPI_BUF_TX(u16)
MXC_SPI_BUF_RX(u32)
MXC_SPI_BUF_TX(u32)
/* First entry is reserved, second entry is valid only if SDHC_SPIEN is set
* (which is currently not the case in this driver)
*/
static int mxc_clkdivs[] = {0, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96, 128, 192,
256, 384, 512, 768, 1024};
/* MX21, MX27 */
static unsigned int spi_imx_clkdiv_1(unsigned int fin,
unsigned int fspi, unsigned int max)
{
int i;
for (i = 2; i < max; i++)
if (fspi * mxc_clkdivs[i] >= fin)
return i;
return max;
}
/* MX1, MX31, MX35, MX51 CSPI */
static unsigned int spi_imx_clkdiv_2(unsigned int fin,
unsigned int fspi)
{
int i, div = 4;
for (i = 0; i < 7; i++) {
if (fspi * div >= fin)
return i;
div <<= 1;
}
return 7;
}
#define MX51_ECSPI_CTRL 0x08
#define MX51_ECSPI_CTRL_ENABLE (1 << 0)
#define MX51_ECSPI_CTRL_XCH (1 << 2)
#define MX51_ECSPI_CTRL_MODE_MASK (0xf << 4)
#define MX51_ECSPI_CTRL_POSTDIV_OFFSET 8
#define MX51_ECSPI_CTRL_PREDIV_OFFSET 12
#define MX51_ECSPI_CTRL_CS(cs) ((cs) << 18)
#define MX51_ECSPI_CTRL_BL_OFFSET 20
#define MX51_ECSPI_CONFIG 0x0c
#define MX51_ECSPI_CONFIG_SCLKPHA(cs) (1 << ((cs) + 0))
#define MX51_ECSPI_CONFIG_SCLKPOL(cs) (1 << ((cs) + 4))
#define MX51_ECSPI_CONFIG_SBBCTRL(cs) (1 << ((cs) + 8))
#define MX51_ECSPI_CONFIG_SSBPOL(cs) (1 << ((cs) + 12))
#define MX51_ECSPI_CONFIG_SCLKCTL(cs) (1 << ((cs) + 20))
#define MX51_ECSPI_INT 0x10
#define MX51_ECSPI_INT_TEEN (1 << 0)
#define MX51_ECSPI_INT_RREN (1 << 3)
#define MX51_ECSPI_STAT 0x18
#define MX51_ECSPI_STAT_RR (1 << 3)
/* MX51 eCSPI */
static unsigned int mx51_ecspi_clkdiv(unsigned int fin, unsigned int fspi,
unsigned int *fres)
{
/*
* there are two 4-bit dividers, the pre-divider divides by
* $pre, the post-divider by 2^$post
*/
unsigned int pre, post;
if (unlikely(fspi > fin))
return 0;
post = fls(fin) - fls(fspi);
if (fin > fspi << post)
post++;
/* now we have: (fin <= fspi << post) with post being minimal */
post = max(4U, post) - 4;
if (unlikely(post > 0xf)) {
pr_err("%s: cannot set clock freq: %u (base freq: %u)\n",
__func__, fspi, fin);
return 0xff;
}
pre = DIV_ROUND_UP(fin, fspi << post) - 1;
pr_debug("%s: fin: %u, fspi: %u, post: %u, pre: %u\n",
__func__, fin, fspi, post, pre);
/* Resulting frequency for the SCLK line. */
*fres = (fin / (pre + 1)) >> post;
return (pre << MX51_ECSPI_CTRL_PREDIV_OFFSET) |
(post << MX51_ECSPI_CTRL_POSTDIV_OFFSET);
}
static void __maybe_unused mx51_ecspi_intctrl(struct spi_imx_data *spi_imx, int enable)
{
unsigned val = 0;
if (enable & MXC_INT_TE)
val |= MX51_ECSPI_INT_TEEN;
if (enable & MXC_INT_RR)
val |= MX51_ECSPI_INT_RREN;
writel(val, spi_imx->base + MX51_ECSPI_INT);
}
static void __maybe_unused mx51_ecspi_trigger(struct spi_imx_data *spi_imx)
{
u32 reg;
reg = readl(spi_imx->base + MX51_ECSPI_CTRL);
reg |= MX51_ECSPI_CTRL_XCH;
writel(reg, spi_imx->base + MX51_ECSPI_CTRL);
}
static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
struct spi_imx_config *config)
{
u32 ctrl = MX51_ECSPI_CTRL_ENABLE, cfg = 0;
u32 clk = config->speed_hz, delay;
/*
* The hardware seems to have a race condition when changing modes. The
* current assumption is that the selection of the channel arrives
* earlier in the hardware than the mode bits when they are written at
* the same time.
* So set master mode for all channels as we do not support slave mode.
*/
ctrl |= MX51_ECSPI_CTRL_MODE_MASK;
/* set clock speed */
ctrl |= mx51_ecspi_clkdiv(spi_imx->spi_clk, config->speed_hz, &clk);
/* set chip select to use */
ctrl |= MX51_ECSPI_CTRL_CS(config->cs);
ctrl |= (config->bpw - 1) << MX51_ECSPI_CTRL_BL_OFFSET;
cfg |= MX51_ECSPI_CONFIG_SBBCTRL(config->cs);
if (config->mode & SPI_CPHA)
cfg |= MX51_ECSPI_CONFIG_SCLKPHA(config->cs);
if (config->mode & SPI_CPOL) {
cfg |= MX51_ECSPI_CONFIG_SCLKPOL(config->cs);
cfg |= MX51_ECSPI_CONFIG_SCLKCTL(config->cs);
}
if (config->mode & SPI_CS_HIGH)
cfg |= MX51_ECSPI_CONFIG_SSBPOL(config->cs);
writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
/*
* Wait until the changes in the configuration register CONFIGREG
* propagate into the hardware. It takes exactly one tick of the
* SCLK clock, but we will wait two SCLK clock just to be sure. The
* effect of the delay it takes for the hardware to apply changes
* is noticable if the SCLK clock run very slow. In such a case, if
* the polarity of SCLK should be inverted, the GPIO ChipSelect might
* be asserted before the SCLK polarity changes, which would disrupt
* the SPI communication as the device on the other end would consider
* the change of SCLK polarity as a clock tick already.
*/
delay = (2 * 1000000) / clk;
if (likely(delay < 10)) /* SCLK is faster than 100 kHz */
udelay(delay);
else /* SCLK is _very_ slow */
usleep_range(delay, delay + 10);
return 0;
}
static int __maybe_unused mx51_ecspi_rx_available(struct spi_imx_data *spi_imx)
{
return readl(spi_imx->base + MX51_ECSPI_STAT) & MX51_ECSPI_STAT_RR;
}
static void __maybe_unused mx51_ecspi_reset(struct spi_imx_data *spi_imx)
{
/* drain receive buffer */
while (mx51_ecspi_rx_available(spi_imx))
readl(spi_imx->base + MXC_CSPIRXDATA);
}
#define MX31_INTREG_TEEN (1 << 0)
#define MX31_INTREG_RREN (1 << 3)
#define MX31_CSPICTRL_ENABLE (1 << 0)
#define MX31_CSPICTRL_MASTER (1 << 1)
#define MX31_CSPICTRL_XCH (1 << 2)
#define MX31_CSPICTRL_POL (1 << 4)
#define MX31_CSPICTRL_PHA (1 << 5)
#define MX31_CSPICTRL_SSCTL (1 << 6)
#define MX31_CSPICTRL_SSPOL (1 << 7)
#define MX31_CSPICTRL_BC_SHIFT 8
#define MX35_CSPICTRL_BL_SHIFT 20
#define MX31_CSPICTRL_CS_SHIFT 24
#define MX35_CSPICTRL_CS_SHIFT 12
#define MX31_CSPICTRL_DR_SHIFT 16
#define MX31_CSPISTATUS 0x14
#define MX31_STATUS_RR (1 << 3)
/* These functions also work for the i.MX35, but be aware that
* the i.MX35 has a slightly different register layout for bits
* we do not use here.
*/
static void __maybe_unused mx31_intctrl(struct spi_imx_data *spi_imx, int enable)
{
unsigned int val = 0;
if (enable & MXC_INT_TE)
val |= MX31_INTREG_TEEN;
if (enable & MXC_INT_RR)
val |= MX31_INTREG_RREN;
writel(val, spi_imx->base + MXC_CSPIINT);
}
static void __maybe_unused mx31_trigger(struct spi_imx_data *spi_imx)
{
unsigned int reg;
reg = readl(spi_imx->base + MXC_CSPICTRL);
reg |= MX31_CSPICTRL_XCH;
writel(reg, spi_imx->base + MXC_CSPICTRL);
}
static int __maybe_unused mx31_config(struct spi_imx_data *spi_imx,
struct spi_imx_config *config)
{
unsigned int reg = MX31_CSPICTRL_ENABLE | MX31_CSPICTRL_MASTER;
int cs = spi_imx->chipselect[config->cs];
reg |= spi_imx_clkdiv_2(spi_imx->spi_clk, config->speed_hz) <<
MX31_CSPICTRL_DR_SHIFT;
if (is_imx35_cspi(spi_imx)) {
reg |= (config->bpw - 1) << MX35_CSPICTRL_BL_SHIFT;
reg |= MX31_CSPICTRL_SSCTL;
} else {
reg |= (config->bpw - 1) << MX31_CSPICTRL_BC_SHIFT;
}
if (config->mode & SPI_CPHA)
reg |= MX31_CSPICTRL_PHA;
if (config->mode & SPI_CPOL)
reg |= MX31_CSPICTRL_POL;
if (config->mode & SPI_CS_HIGH)
reg |= MX31_CSPICTRL_SSPOL;
if (cs < 0)
reg |= (cs + 32) <<
(is_imx35_cspi(spi_imx) ? MX35_CSPICTRL_CS_SHIFT :
MX31_CSPICTRL_CS_SHIFT);
writel(reg, spi_imx->base + MXC_CSPICTRL);
return 0;
}
static int __maybe_unused mx31_rx_available(struct spi_imx_data *spi_imx)
{
return readl(spi_imx->base + MX31_CSPISTATUS) & MX31_STATUS_RR;
}
static void __maybe_unused mx31_reset(struct spi_imx_data *spi_imx)
{
/* drain receive buffer */
while (readl(spi_imx->base + MX31_CSPISTATUS) & MX31_STATUS_RR)
readl(spi_imx->base + MXC_CSPIRXDATA);
}
#define MX21_INTREG_RR (1 << 4)
#define MX21_INTREG_TEEN (1 << 9)
#define MX21_INTREG_RREN (1 << 13)
#define MX21_CSPICTRL_POL (1 << 5)
#define MX21_CSPICTRL_PHA (1 << 6)
#define MX21_CSPICTRL_SSPOL (1 << 8)
#define MX21_CSPICTRL_XCH (1 << 9)
#define MX21_CSPICTRL_ENABLE (1 << 10)
#define MX21_CSPICTRL_MASTER (1 << 11)
#define MX21_CSPICTRL_DR_SHIFT 14
#define MX21_CSPICTRL_CS_SHIFT 19
static void __maybe_unused mx21_intctrl(struct spi_imx_data *spi_imx, int enable)
{
unsigned int val = 0;
if (enable & MXC_INT_TE)
val |= MX21_INTREG_TEEN;
if (enable & MXC_INT_RR)
val |= MX21_INTREG_RREN;
writel(val, spi_imx->base + MXC_CSPIINT);
}
static void __maybe_unused mx21_trigger(struct spi_imx_data *spi_imx)
{
unsigned int reg;
reg = readl(spi_imx->base + MXC_CSPICTRL);
reg |= MX21_CSPICTRL_XCH;
writel(reg, spi_imx->base + MXC_CSPICTRL);
}
static int __maybe_unused mx21_config(struct spi_imx_data *spi_imx,
struct spi_imx_config *config)
{
unsigned int reg = MX21_CSPICTRL_ENABLE | MX21_CSPICTRL_MASTER;
int cs = spi_imx->chipselect[config->cs];
unsigned int max = is_imx27_cspi(spi_imx) ? 16 : 18;
reg |= spi_imx_clkdiv_1(spi_imx->spi_clk, config->speed_hz, max) <<
MX21_CSPICTRL_DR_SHIFT;
reg |= config->bpw - 1;
if (config->mode & SPI_CPHA)
reg |= MX21_CSPICTRL_PHA;
if (config->mode & SPI_CPOL)
reg |= MX21_CSPICTRL_POL;
if (config->mode & SPI_CS_HIGH)
reg |= MX21_CSPICTRL_SSPOL;
if (cs < 0)
reg |= (cs + 32) << MX21_CSPICTRL_CS_SHIFT;
writel(reg, spi_imx->base + MXC_CSPICTRL);
return 0;
}
static int __maybe_unused mx21_rx_available(struct spi_imx_data *spi_imx)
{
return readl(spi_imx->base + MXC_CSPIINT) & MX21_INTREG_RR;
}
static void __maybe_unused mx21_reset(struct spi_imx_data *spi_imx)
{
writel(1, spi_imx->base + MXC_RESET);
}
#define MX1_INTREG_RR (1 << 3)
#define MX1_INTREG_TEEN (1 << 8)
#define MX1_INTREG_RREN (1 << 11)
#define MX1_CSPICTRL_POL (1 << 4)
#define MX1_CSPICTRL_PHA (1 << 5)
#define MX1_CSPICTRL_XCH (1 << 8)
#define MX1_CSPICTRL_ENABLE (1 << 9)
#define MX1_CSPICTRL_MASTER (1 << 10)
#define MX1_CSPICTRL_DR_SHIFT 13
static void __maybe_unused mx1_intctrl(struct spi_imx_data *spi_imx, int enable)
{
unsigned int val = 0;
if (enable & MXC_INT_TE)
val |= MX1_INTREG_TEEN;
if (enable & MXC_INT_RR)
val |= MX1_INTREG_RREN;
writel(val, spi_imx->base + MXC_CSPIINT);
}
static void __maybe_unused mx1_trigger(struct spi_imx_data *spi_imx)
{
unsigned int reg;
reg = readl(spi_imx->base + MXC_CSPICTRL);
reg |= MX1_CSPICTRL_XCH;
writel(reg, spi_imx->base + MXC_CSPICTRL);
}
static int __maybe_unused mx1_config(struct spi_imx_data *spi_imx,
struct spi_imx_config *config)
{
unsigned int reg = MX1_CSPICTRL_ENABLE | MX1_CSPICTRL_MASTER;
reg |= spi_imx_clkdiv_2(spi_imx->spi_clk, config->speed_hz) <<
MX1_CSPICTRL_DR_SHIFT;
reg |= config->bpw - 1;
if (config->mode & SPI_CPHA)
reg |= MX1_CSPICTRL_PHA;
if (config->mode & SPI_CPOL)
reg |= MX1_CSPICTRL_POL;
writel(reg, spi_imx->base + MXC_CSPICTRL);
return 0;
}
static int __maybe_unused mx1_rx_available(struct spi_imx_data *spi_imx)
{
return readl(spi_imx->base + MXC_CSPIINT) & MX1_INTREG_RR;
}
static void __maybe_unused mx1_reset(struct spi_imx_data *spi_imx)
{
writel(1, spi_imx->base + MXC_RESET);
}
static struct spi_imx_devtype_data imx1_cspi_devtype_data = {
.intctrl = mx1_intctrl,
.config = mx1_config,
.trigger = mx1_trigger,
.rx_available = mx1_rx_available,
.reset = mx1_reset,
.devtype = IMX1_CSPI,
};
static struct spi_imx_devtype_data imx21_cspi_devtype_data = {
.intctrl = mx21_intctrl,
.config = mx21_config,
.trigger = mx21_trigger,
.rx_available = mx21_rx_available,
.reset = mx21_reset,
.devtype = IMX21_CSPI,
};
static struct spi_imx_devtype_data imx27_cspi_devtype_data = {
/* i.mx27 cspi shares the functions with i.mx21 one */
.intctrl = mx21_intctrl,
.config = mx21_config,
.trigger = mx21_trigger,
.rx_available = mx21_rx_available,
.reset = mx21_reset,
.devtype = IMX27_CSPI,
};
static struct spi_imx_devtype_data imx31_cspi_devtype_data = {
.intctrl = mx31_intctrl,
.config = mx31_config,
.trigger = mx31_trigger,
.rx_available = mx31_rx_available,
.reset = mx31_reset,
.devtype = IMX31_CSPI,
};
static struct spi_imx_devtype_data imx35_cspi_devtype_data = {
/* i.mx35 and later cspi shares the functions with i.mx31 one */
.intctrl = mx31_intctrl,
.config = mx31_config,
.trigger = mx31_trigger,
.rx_available = mx31_rx_available,
.reset = mx31_reset,
.devtype = IMX35_CSPI,
};
static struct spi_imx_devtype_data imx51_ecspi_devtype_data = {
.intctrl = mx51_ecspi_intctrl,
.config = mx51_ecspi_config,
.trigger = mx51_ecspi_trigger,
.rx_available = mx51_ecspi_rx_available,
.reset = mx51_ecspi_reset,
.devtype = IMX51_ECSPI,
};
static struct platform_device_id spi_imx_devtype[] = {
{
.name = "imx1-cspi",
.driver_data = (kernel_ulong_t) &imx1_cspi_devtype_data,
}, {
.name = "imx21-cspi",
.driver_data = (kernel_ulong_t) &imx21_cspi_devtype_data,
}, {
.name = "imx27-cspi",
.driver_data = (kernel_ulong_t) &imx27_cspi_devtype_data,
}, {
.name = "imx31-cspi",
.driver_data = (kernel_ulong_t) &imx31_cspi_devtype_data,
}, {
.name = "imx35-cspi",
.driver_data = (kernel_ulong_t) &imx35_cspi_devtype_data,
}, {
.name = "imx51-ecspi",
.driver_data = (kernel_ulong_t) &imx51_ecspi_devtype_data,
}, {
/* sentinel */
}
};
static const struct of_device_id spi_imx_dt_ids[] = {
{ .compatible = "fsl,imx1-cspi", .data = &imx1_cspi_devtype_data, },
{ .compatible = "fsl,imx21-cspi", .data = &imx21_cspi_devtype_data, },
{ .compatible = "fsl,imx27-cspi", .data = &imx27_cspi_devtype_data, },
{ .compatible = "fsl,imx31-cspi", .data = &imx31_cspi_devtype_data, },
{ .compatible = "fsl,imx35-cspi", .data = &imx35_cspi_devtype_data, },
{ .compatible = "fsl,imx51-ecspi", .data = &imx51_ecspi_devtype_data, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, spi_imx_dt_ids);
static void spi_imx_chipselect(struct spi_device *spi, int is_active)
{
struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
int gpio = spi_imx->chipselect[spi->chip_select];
int active = is_active != BITBANG_CS_INACTIVE;
int dev_is_lowactive = !(spi->mode & SPI_CS_HIGH);
if (!gpio_is_valid(gpio))
return;
gpio_set_value(gpio, dev_is_lowactive ^ active);
}
static void spi_imx_push(struct spi_imx_data *spi_imx)
{
while (spi_imx->txfifo < spi_imx_get_fifosize(spi_imx)) {
if (!spi_imx->count)
break;
spi_imx->tx(spi_imx);
spi_imx->txfifo++;
}
spi_imx->devtype_data->trigger(spi_imx);
}
static irqreturn_t spi_imx_isr(int irq, void *dev_id)
{
struct spi_imx_data *spi_imx = dev_id;
while (spi_imx->devtype_data->rx_available(spi_imx)) {
spi_imx->rx(spi_imx);
spi_imx->txfifo--;
}
if (spi_imx->count) {
spi_imx_push(spi_imx);
return IRQ_HANDLED;
}
if (spi_imx->txfifo) {
/* No data left to push, but still waiting for rx data,
* enable receive data available interrupt.
*/
spi_imx->devtype_data->intctrl(
spi_imx, MXC_INT_RR);
return IRQ_HANDLED;
}
spi_imx->devtype_data->intctrl(spi_imx, 0);
complete(&spi_imx->xfer_done);
return IRQ_HANDLED;
}
static int spi_imx_setupxfer(struct spi_device *spi,
struct spi_transfer *t)
{
struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
struct spi_imx_config config;
config.bpw = t ? t->bits_per_word : spi->bits_per_word;
config.speed_hz = t ? t->speed_hz : spi->max_speed_hz;
config.mode = spi->mode;
config.cs = spi->chip_select;
if (!config.speed_hz)
config.speed_hz = spi->max_speed_hz;
if (!config.bpw)
config.bpw = spi->bits_per_word;
/* Initialize the functions for transfer */
if (config.bpw <= 8) {
spi_imx->rx = spi_imx_buf_rx_u8;
spi_imx->tx = spi_imx_buf_tx_u8;
} else if (config.bpw <= 16) {
spi_imx->rx = spi_imx_buf_rx_u16;
spi_imx->tx = spi_imx_buf_tx_u16;
} else {
spi_imx->rx = spi_imx_buf_rx_u32;
spi_imx->tx = spi_imx_buf_tx_u32;
}
spi_imx->devtype_data->config(spi_imx, &config);
return 0;
}
static int spi_imx_transfer(struct spi_device *spi,
struct spi_transfer *transfer)
{
struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
spi_imx->tx_buf = transfer->tx_buf;
spi_imx->rx_buf = transfer->rx_buf;
spi_imx->count = transfer->len;
spi_imx->txfifo = 0;
init_completion(&spi_imx->xfer_done);
spi_imx_push(spi_imx);
spi_imx->devtype_data->intctrl(spi_imx, MXC_INT_TE);
wait_for_completion(&spi_imx->xfer_done);
return transfer->len;
}
static int spi_imx_setup(struct spi_device *spi)
{
struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
int gpio = spi_imx->chipselect[spi->chip_select];
dev_dbg(&spi->dev, "%s: mode %d, %u bpw, %d hz\n", __func__,
spi->mode, spi->bits_per_word, spi->max_speed_hz);
if (gpio_is_valid(gpio))
gpio_direction_output(gpio, spi->mode & SPI_CS_HIGH ? 0 : 1);
spi_imx_chipselect(spi, BITBANG_CS_INACTIVE);
return 0;
}
static void spi_imx_cleanup(struct spi_device *spi)
{
}
static int
spi_imx_prepare_message(struct spi_master *master, struct spi_message *msg)
{
struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
int ret;
ret = clk_enable(spi_imx->clk_per);
if (ret)
return ret;
ret = clk_enable(spi_imx->clk_ipg);
if (ret) {
clk_disable(spi_imx->clk_per);
return ret;
}
return 0;
}
static int
spi_imx_unprepare_message(struct spi_master *master, struct spi_message *msg)
{
struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
clk_disable(spi_imx->clk_ipg);
clk_disable(spi_imx->clk_per);
return 0;
}
static int spi_imx_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
const struct of_device_id *of_id =
of_match_device(spi_imx_dt_ids, &pdev->dev);
struct spi_imx_master *mxc_platform_info =
dev_get_platdata(&pdev->dev);
struct spi_master *master;
struct spi_imx_data *spi_imx;
struct resource *res;
int i, ret, num_cs;
if (!np && !mxc_platform_info) {
dev_err(&pdev->dev, "can't get the platform data\n");
return -EINVAL;
}
ret = of_property_read_u32(np, "fsl,spi-num-chipselects", &num_cs);
if (ret < 0) {
if (mxc_platform_info)
num_cs = mxc_platform_info->num_chipselect;
else
return ret;
}
master = spi_alloc_master(&pdev->dev,
sizeof(struct spi_imx_data) + sizeof(int) * num_cs);
if (!master)
return -ENOMEM;
platform_set_drvdata(pdev, master);
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
master->bus_num = pdev->id;
master->num_chipselect = num_cs;
spi_imx = spi_master_get_devdata(master);
spi_imx->bitbang.master = master;
for (i = 0; i < master->num_chipselect; i++) {
int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
if (!gpio_is_valid(cs_gpio) && mxc_platform_info)
cs_gpio = mxc_platform_info->chipselect[i];
spi_imx->chipselect[i] = cs_gpio;
if (!gpio_is_valid(cs_gpio))
continue;
ret = devm_gpio_request(&pdev->dev, spi_imx->chipselect[i],
DRIVER_NAME);
if (ret) {
dev_err(&pdev->dev, "can't get cs gpios\n");
goto out_master_put;
}
}
spi_imx->bitbang.chipselect = spi_imx_chipselect;
spi_imx->bitbang.setup_transfer = spi_imx_setupxfer;
spi_imx->bitbang.txrx_bufs = spi_imx_transfer;
spi_imx->bitbang.master->setup = spi_imx_setup;
spi_imx->bitbang.master->cleanup = spi_imx_cleanup;
spi_imx->bitbang.master->prepare_message = spi_imx_prepare_message;
spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
init_completion(&spi_imx->xfer_done);
spi_imx->devtype_data = of_id ? of_id->data :
(struct spi_imx_devtype_data *) pdev->id_entry->driver_data;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
spi_imx->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(spi_imx->base)) {
ret = PTR_ERR(spi_imx->base);
goto out_master_put;
}
spi_imx->irq = platform_get_irq(pdev, 0);
if (spi_imx->irq < 0) {
ret = -EINVAL;
goto out_master_put;
}
ret = devm_request_irq(&pdev->dev, spi_imx->irq, spi_imx_isr, 0,
DRIVER_NAME, spi_imx);
if (ret) {
dev_err(&pdev->dev, "can't get irq%d: %d\n", spi_imx->irq, ret);
goto out_master_put;
}
spi_imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
if (IS_ERR(spi_imx->clk_ipg)) {
ret = PTR_ERR(spi_imx->clk_ipg);
goto out_master_put;
}
spi_imx->clk_per = devm_clk_get(&pdev->dev, "per");
if (IS_ERR(spi_imx->clk_per)) {
ret = PTR_ERR(spi_imx->clk_per);
goto out_master_put;
}
ret = clk_prepare_enable(spi_imx->clk_per);
if (ret)
goto out_master_put;
ret = clk_prepare_enable(spi_imx->clk_ipg);
if (ret)
goto out_put_per;
spi_imx->spi_clk = clk_get_rate(spi_imx->clk_per);
spi_imx->devtype_data->reset(spi_imx);
spi_imx->devtype_data->intctrl(spi_imx, 0);
master->dev.of_node = pdev->dev.of_node;
ret = spi_bitbang_start(&spi_imx->bitbang);
if (ret) {
dev_err(&pdev->dev, "bitbang start failed with %d\n", ret);
goto out_clk_put;
}
dev_info(&pdev->dev, "probed\n");
clk_disable(spi_imx->clk_ipg);
clk_disable(spi_imx->clk_per);
return ret;
out_clk_put:
clk_disable_unprepare(spi_imx->clk_ipg);
out_put_per:
clk_disable_unprepare(spi_imx->clk_per);
out_master_put:
spi_master_put(master);
return ret;
}
static int spi_imx_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
spi_bitbang_stop(&spi_imx->bitbang);
writel(0, spi_imx->base + MXC_CSPICTRL);
clk_disable_unprepare(spi_imx->clk_ipg);
clk_disable_unprepare(spi_imx->clk_per);
spi_master_put(master);
return 0;
}
static struct platform_driver spi_imx_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.of_match_table = spi_imx_dt_ids,
},
.id_table = spi_imx_devtype,
.probe = spi_imx_probe,
.remove = spi_imx_remove,
};
module_platform_driver(spi_imx_driver);
MODULE_DESCRIPTION("SPI Master Controller driver");
MODULE_AUTHOR("Sascha Hauer, Pengutronix");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRIVER_NAME);