linux/drivers/spi/spi-ep93xx.c
Linus Torvalds 9bff9dfc51 spi: Updates for v5.2
One small feature was added this release but the bulk of the diffstat
 and the changelog comes from the fact that several older drivers got
 some fairly hefty reworks and a couple of new drivers were added:
 
  - Support for detailed control of timing around chip selects from
    Sowjanya Komatineni.
  - A big set of fixes and imrovements for the Tegra114 driver from
    Sowjanya Komatineni.
  - A big simplification of the GPIO driver from Andrey Smirnov.
  - DMA support and fixes for the Freescale LPSPI driver from Clark Wang.
  - Fixes and optimizations for the bcm2835aux from Martin Sparl.
  - New drivers for Mediatek MT7621 (graduated from staging) and Zynq QSPI.
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Merge tag 'spi-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

Pull spi updates from Mark Brown:
 "One small feature was added this release but the bulk of the diffstat
  and the changelog comes from the fact that several older drivers got
  some fairly hefty reworks and a couple of new drivers were added:

   - Support for detailed control of timing around chip selects from
     Sowjanya Komatineni.

   - A big set of fixes and imrovements for the Tegra114 driver from
     Sowjanya Komatineni.

   - A big simplification of the GPIO driver from Andrey Smirnov.

   - DMA support and fixes for the Freescale LPSPI driver from Clark
     Wang.

   - Fixes and optimizations for the bcm2835aux from Martin Sparl.

   - New drivers for Mediatek MT7621 (graduated from staging) and Zynq
     QSPI"

[ This is a so-called "evil merge" that additionally removes a warning
  due to an unused variable 'i' introduced by commit 1dfbf334f1 ("spi:
  ep93xx: Convert to use CS GPIO descriptors")     - Linus ]

* tag 'spi-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (127 commits)
  spi: rspi: Fix handling of QSPI code when transmit and receive
  spi: atmel-quadspi: fix crash while suspending
  spi: stm32: return the get_irq error
  spi: tegra114: fix PIO transfer
  spi: pxa2xx: fix SCR (divisor) calculation
  spi: Clear SPI_CS_HIGH flag from bad_bits for GPIO chip-select
  spi: ep93xx: Convert to use CS GPIO descriptors
  spi: AD ASoC: declare missing of table
  spi: spi-mem: zynq-qspi: Fix build error on architectures missing readsl/writesl
  spi: stm32-qspi: manage the get_irq error case
  spi/spi-bcm2835: Split transfers that exceed DLEN
  spi: expand mode support
  dt-bindings: spi: spi-mt65xx: add support for MT8516
  spi: pxa2xx: Add support for Intel Comet Lake
  spi/trace: Cap buffer contents at 64 bytes
  spi: Release spi_res after finalizing message
  spi: Remove warning in spi_split_transfers_maxsize()
  spi: Remove one needless transfer speed fall back case
  spi: sh-msiof: Document r8a77470 bindings
  spi: pxa2xx: use a module softdep for dw_dmac
  ...
2019-05-07 07:44:33 -07:00

772 lines
19 KiB
C

/*
* Driver for Cirrus Logic EP93xx SPI controller.
*
* Copyright (C) 2010-2011 Mika Westerberg
*
* Explicit FIFO handling code was inspired by amba-pl022 driver.
*
* Chip select support using other than built-in GPIOs by H. Hartley Sweeten.
*
* For more information about the SPI controller see documentation on Cirrus
* Logic web site:
* http://www.cirrus.com/en/pubs/manual/EP93xx_Users_Guide_UM1.pdf
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/scatterlist.h>
#include <linux/spi/spi.h>
#include <linux/platform_data/dma-ep93xx.h>
#include <linux/platform_data/spi-ep93xx.h>
#define SSPCR0 0x0000
#define SSPCR0_MODE_SHIFT 6
#define SSPCR0_SCR_SHIFT 8
#define SSPCR1 0x0004
#define SSPCR1_RIE BIT(0)
#define SSPCR1_TIE BIT(1)
#define SSPCR1_RORIE BIT(2)
#define SSPCR1_LBM BIT(3)
#define SSPCR1_SSE BIT(4)
#define SSPCR1_MS BIT(5)
#define SSPCR1_SOD BIT(6)
#define SSPDR 0x0008
#define SSPSR 0x000c
#define SSPSR_TFE BIT(0)
#define SSPSR_TNF BIT(1)
#define SSPSR_RNE BIT(2)
#define SSPSR_RFF BIT(3)
#define SSPSR_BSY BIT(4)
#define SSPCPSR 0x0010
#define SSPIIR 0x0014
#define SSPIIR_RIS BIT(0)
#define SSPIIR_TIS BIT(1)
#define SSPIIR_RORIS BIT(2)
#define SSPICR SSPIIR
/* timeout in milliseconds */
#define SPI_TIMEOUT 5
/* maximum depth of RX/TX FIFO */
#define SPI_FIFO_SIZE 8
/**
* struct ep93xx_spi - EP93xx SPI controller structure
* @clk: clock for the controller
* @mmio: pointer to ioremap()'d registers
* @sspdr_phys: physical address of the SSPDR register
* @tx: current byte in transfer to transmit
* @rx: current byte in transfer to receive
* @fifo_level: how full is FIFO (%0..%SPI_FIFO_SIZE - %1). Receiving one
* frame decreases this level and sending one frame increases it.
* @dma_rx: RX DMA channel
* @dma_tx: TX DMA channel
* @dma_rx_data: RX parameters passed to the DMA engine
* @dma_tx_data: TX parameters passed to the DMA engine
* @rx_sgt: sg table for RX transfers
* @tx_sgt: sg table for TX transfers
* @zeropage: dummy page used as RX buffer when only TX buffer is passed in by
* the client
*/
struct ep93xx_spi {
struct clk *clk;
void __iomem *mmio;
unsigned long sspdr_phys;
size_t tx;
size_t rx;
size_t fifo_level;
struct dma_chan *dma_rx;
struct dma_chan *dma_tx;
struct ep93xx_dma_data dma_rx_data;
struct ep93xx_dma_data dma_tx_data;
struct sg_table rx_sgt;
struct sg_table tx_sgt;
void *zeropage;
};
/* converts bits per word to CR0.DSS value */
#define bits_per_word_to_dss(bpw) ((bpw) - 1)
/**
* ep93xx_spi_calc_divisors() - calculates SPI clock divisors
* @master: SPI master
* @rate: desired SPI output clock rate
* @div_cpsr: pointer to return the cpsr (pre-scaler) divider
* @div_scr: pointer to return the scr divider
*/
static int ep93xx_spi_calc_divisors(struct spi_master *master,
u32 rate, u8 *div_cpsr, u8 *div_scr)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
unsigned long spi_clk_rate = clk_get_rate(espi->clk);
int cpsr, scr;
/*
* Make sure that max value is between values supported by the
* controller.
*/
rate = clamp(rate, master->min_speed_hz, master->max_speed_hz);
/*
* Calculate divisors so that we can get speed according the
* following formula:
* rate = spi_clock_rate / (cpsr * (1 + scr))
*
* cpsr must be even number and starts from 2, scr can be any number
* between 0 and 255.
*/
for (cpsr = 2; cpsr <= 254; cpsr += 2) {
for (scr = 0; scr <= 255; scr++) {
if ((spi_clk_rate / (cpsr * (scr + 1))) <= rate) {
*div_scr = (u8)scr;
*div_cpsr = (u8)cpsr;
return 0;
}
}
}
return -EINVAL;
}
static int ep93xx_spi_chip_setup(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *xfer)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
u8 dss = bits_per_word_to_dss(xfer->bits_per_word);
u8 div_cpsr = 0;
u8 div_scr = 0;
u16 cr0;
int err;
err = ep93xx_spi_calc_divisors(master, xfer->speed_hz,
&div_cpsr, &div_scr);
if (err)
return err;
cr0 = div_scr << SSPCR0_SCR_SHIFT;
cr0 |= (spi->mode & (SPI_CPHA | SPI_CPOL)) << SSPCR0_MODE_SHIFT;
cr0 |= dss;
dev_dbg(&master->dev, "setup: mode %d, cpsr %d, scr %d, dss %d\n",
spi->mode, div_cpsr, div_scr, dss);
dev_dbg(&master->dev, "setup: cr0 %#x\n", cr0);
writel(div_cpsr, espi->mmio + SSPCPSR);
writel(cr0, espi->mmio + SSPCR0);
return 0;
}
static void ep93xx_do_write(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct spi_transfer *xfer = master->cur_msg->state;
u32 val = 0;
if (xfer->bits_per_word > 8) {
if (xfer->tx_buf)
val = ((u16 *)xfer->tx_buf)[espi->tx];
espi->tx += 2;
} else {
if (xfer->tx_buf)
val = ((u8 *)xfer->tx_buf)[espi->tx];
espi->tx += 1;
}
writel(val, espi->mmio + SSPDR);
}
static void ep93xx_do_read(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct spi_transfer *xfer = master->cur_msg->state;
u32 val;
val = readl(espi->mmio + SSPDR);
if (xfer->bits_per_word > 8) {
if (xfer->rx_buf)
((u16 *)xfer->rx_buf)[espi->rx] = val;
espi->rx += 2;
} else {
if (xfer->rx_buf)
((u8 *)xfer->rx_buf)[espi->rx] = val;
espi->rx += 1;
}
}
/**
* ep93xx_spi_read_write() - perform next RX/TX transfer
* @espi: ep93xx SPI controller struct
*
* This function transfers next bytes (or half-words) to/from RX/TX FIFOs. If
* called several times, the whole transfer will be completed. Returns
* %-EINPROGRESS when current transfer was not yet completed otherwise %0.
*
* When this function is finished, RX FIFO should be empty and TX FIFO should be
* full.
*/
static int ep93xx_spi_read_write(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct spi_transfer *xfer = master->cur_msg->state;
/* read as long as RX FIFO has frames in it */
while ((readl(espi->mmio + SSPSR) & SSPSR_RNE)) {
ep93xx_do_read(master);
espi->fifo_level--;
}
/* write as long as TX FIFO has room */
while (espi->fifo_level < SPI_FIFO_SIZE && espi->tx < xfer->len) {
ep93xx_do_write(master);
espi->fifo_level++;
}
if (espi->rx == xfer->len)
return 0;
return -EINPROGRESS;
}
static enum dma_transfer_direction
ep93xx_dma_data_to_trans_dir(enum dma_data_direction dir)
{
switch (dir) {
case DMA_TO_DEVICE:
return DMA_MEM_TO_DEV;
case DMA_FROM_DEVICE:
return DMA_DEV_TO_MEM;
default:
return DMA_TRANS_NONE;
}
}
/**
* ep93xx_spi_dma_prepare() - prepares a DMA transfer
* @master: SPI master
* @dir: DMA transfer direction
*
* Function configures the DMA, maps the buffer and prepares the DMA
* descriptor. Returns a valid DMA descriptor in case of success and ERR_PTR
* in case of failure.
*/
static struct dma_async_tx_descriptor *
ep93xx_spi_dma_prepare(struct spi_master *master,
enum dma_data_direction dir)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct spi_transfer *xfer = master->cur_msg->state;
struct dma_async_tx_descriptor *txd;
enum dma_slave_buswidth buswidth;
struct dma_slave_config conf;
struct scatterlist *sg;
struct sg_table *sgt;
struct dma_chan *chan;
const void *buf, *pbuf;
size_t len = xfer->len;
int i, ret, nents;
if (xfer->bits_per_word > 8)
buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
else
buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
memset(&conf, 0, sizeof(conf));
conf.direction = ep93xx_dma_data_to_trans_dir(dir);
if (dir == DMA_FROM_DEVICE) {
chan = espi->dma_rx;
buf = xfer->rx_buf;
sgt = &espi->rx_sgt;
conf.src_addr = espi->sspdr_phys;
conf.src_addr_width = buswidth;
} else {
chan = espi->dma_tx;
buf = xfer->tx_buf;
sgt = &espi->tx_sgt;
conf.dst_addr = espi->sspdr_phys;
conf.dst_addr_width = buswidth;
}
ret = dmaengine_slave_config(chan, &conf);
if (ret)
return ERR_PTR(ret);
/*
* We need to split the transfer into PAGE_SIZE'd chunks. This is
* because we are using @espi->zeropage to provide a zero RX buffer
* for the TX transfers and we have only allocated one page for that.
*
* For performance reasons we allocate a new sg_table only when
* needed. Otherwise we will re-use the current one. Eventually the
* last sg_table is released in ep93xx_spi_release_dma().
*/
nents = DIV_ROUND_UP(len, PAGE_SIZE);
if (nents != sgt->nents) {
sg_free_table(sgt);
ret = sg_alloc_table(sgt, nents, GFP_KERNEL);
if (ret)
return ERR_PTR(ret);
}
pbuf = buf;
for_each_sg(sgt->sgl, sg, sgt->nents, i) {
size_t bytes = min_t(size_t, len, PAGE_SIZE);
if (buf) {
sg_set_page(sg, virt_to_page(pbuf), bytes,
offset_in_page(pbuf));
} else {
sg_set_page(sg, virt_to_page(espi->zeropage),
bytes, 0);
}
pbuf += bytes;
len -= bytes;
}
if (WARN_ON(len)) {
dev_warn(&master->dev, "len = %zu expected 0!\n", len);
return ERR_PTR(-EINVAL);
}
nents = dma_map_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
if (!nents)
return ERR_PTR(-ENOMEM);
txd = dmaengine_prep_slave_sg(chan, sgt->sgl, nents, conf.direction,
DMA_CTRL_ACK);
if (!txd) {
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
return ERR_PTR(-ENOMEM);
}
return txd;
}
/**
* ep93xx_spi_dma_finish() - finishes with a DMA transfer
* @master: SPI master
* @dir: DMA transfer direction
*
* Function finishes with the DMA transfer. After this, the DMA buffer is
* unmapped.
*/
static void ep93xx_spi_dma_finish(struct spi_master *master,
enum dma_data_direction dir)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct dma_chan *chan;
struct sg_table *sgt;
if (dir == DMA_FROM_DEVICE) {
chan = espi->dma_rx;
sgt = &espi->rx_sgt;
} else {
chan = espi->dma_tx;
sgt = &espi->tx_sgt;
}
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
}
static void ep93xx_spi_dma_callback(void *callback_param)
{
struct spi_master *master = callback_param;
ep93xx_spi_dma_finish(master, DMA_TO_DEVICE);
ep93xx_spi_dma_finish(master, DMA_FROM_DEVICE);
spi_finalize_current_transfer(master);
}
static int ep93xx_spi_dma_transfer(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct dma_async_tx_descriptor *rxd, *txd;
rxd = ep93xx_spi_dma_prepare(master, DMA_FROM_DEVICE);
if (IS_ERR(rxd)) {
dev_err(&master->dev, "DMA RX failed: %ld\n", PTR_ERR(rxd));
return PTR_ERR(rxd);
}
txd = ep93xx_spi_dma_prepare(master, DMA_TO_DEVICE);
if (IS_ERR(txd)) {
ep93xx_spi_dma_finish(master, DMA_FROM_DEVICE);
dev_err(&master->dev, "DMA TX failed: %ld\n", PTR_ERR(txd));
return PTR_ERR(txd);
}
/* We are ready when RX is done */
rxd->callback = ep93xx_spi_dma_callback;
rxd->callback_param = master;
/* Now submit both descriptors and start DMA */
dmaengine_submit(rxd);
dmaengine_submit(txd);
dma_async_issue_pending(espi->dma_rx);
dma_async_issue_pending(espi->dma_tx);
/* signal that we need to wait for completion */
return 1;
}
static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
{
struct spi_master *master = dev_id;
struct ep93xx_spi *espi = spi_master_get_devdata(master);
u32 val;
/*
* If we got ROR (receive overrun) interrupt we know that something is
* wrong. Just abort the message.
*/
if (readl(espi->mmio + SSPIIR) & SSPIIR_RORIS) {
/* clear the overrun interrupt */
writel(0, espi->mmio + SSPICR);
dev_warn(&master->dev,
"receive overrun, aborting the message\n");
master->cur_msg->status = -EIO;
} else {
/*
* Interrupt is either RX (RIS) or TX (TIS). For both cases we
* simply execute next data transfer.
*/
if (ep93xx_spi_read_write(master)) {
/*
* In normal case, there still is some processing left
* for current transfer. Let's wait for the next
* interrupt then.
*/
return IRQ_HANDLED;
}
}
/*
* Current transfer is finished, either with error or with success. In
* any case we disable interrupts and notify the worker to handle
* any post-processing of the message.
*/
val = readl(espi->mmio + SSPCR1);
val &= ~(SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
writel(val, espi->mmio + SSPCR1);
spi_finalize_current_transfer(master);
return IRQ_HANDLED;
}
static int ep93xx_spi_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *xfer)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
u32 val;
int ret;
ret = ep93xx_spi_chip_setup(master, spi, xfer);
if (ret) {
dev_err(&master->dev, "failed to setup chip for transfer\n");
return ret;
}
master->cur_msg->state = xfer;
espi->rx = 0;
espi->tx = 0;
/*
* There is no point of setting up DMA for the transfers which will
* fit into the FIFO and can be transferred with a single interrupt.
* So in these cases we will be using PIO and don't bother for DMA.
*/
if (espi->dma_rx && xfer->len > SPI_FIFO_SIZE)
return ep93xx_spi_dma_transfer(master);
/* Using PIO so prime the TX FIFO and enable interrupts */
ep93xx_spi_read_write(master);
val = readl(espi->mmio + SSPCR1);
val |= (SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
writel(val, espi->mmio + SSPCR1);
/* signal that we need to wait for completion */
return 1;
}
static int ep93xx_spi_prepare_message(struct spi_master *master,
struct spi_message *msg)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
unsigned long timeout;
/*
* Just to be sure: flush any data from RX FIFO.
*/
timeout = jiffies + msecs_to_jiffies(SPI_TIMEOUT);
while (readl(espi->mmio + SSPSR) & SSPSR_RNE) {
if (time_after(jiffies, timeout)) {
dev_warn(&master->dev,
"timeout while flushing RX FIFO\n");
return -ETIMEDOUT;
}
readl(espi->mmio + SSPDR);
}
/*
* We explicitly handle FIFO level. This way we don't have to check TX
* FIFO status using %SSPSR_TNF bit which may cause RX FIFO overruns.
*/
espi->fifo_level = 0;
return 0;
}
static int ep93xx_spi_prepare_hardware(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
u32 val;
int ret;
ret = clk_enable(espi->clk);
if (ret)
return ret;
val = readl(espi->mmio + SSPCR1);
val |= SSPCR1_SSE;
writel(val, espi->mmio + SSPCR1);
return 0;
}
static int ep93xx_spi_unprepare_hardware(struct spi_master *master)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
u32 val;
val = readl(espi->mmio + SSPCR1);
val &= ~SSPCR1_SSE;
writel(val, espi->mmio + SSPCR1);
clk_disable(espi->clk);
return 0;
}
static bool ep93xx_spi_dma_filter(struct dma_chan *chan, void *filter_param)
{
if (ep93xx_dma_chan_is_m2p(chan))
return false;
chan->private = filter_param;
return true;
}
static int ep93xx_spi_setup_dma(struct ep93xx_spi *espi)
{
dma_cap_mask_t mask;
int ret;
espi->zeropage = (void *)get_zeroed_page(GFP_KERNEL);
if (!espi->zeropage)
return -ENOMEM;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
espi->dma_rx_data.port = EP93XX_DMA_SSP;
espi->dma_rx_data.direction = DMA_DEV_TO_MEM;
espi->dma_rx_data.name = "ep93xx-spi-rx";
espi->dma_rx = dma_request_channel(mask, ep93xx_spi_dma_filter,
&espi->dma_rx_data);
if (!espi->dma_rx) {
ret = -ENODEV;
goto fail_free_page;
}
espi->dma_tx_data.port = EP93XX_DMA_SSP;
espi->dma_tx_data.direction = DMA_MEM_TO_DEV;
espi->dma_tx_data.name = "ep93xx-spi-tx";
espi->dma_tx = dma_request_channel(mask, ep93xx_spi_dma_filter,
&espi->dma_tx_data);
if (!espi->dma_tx) {
ret = -ENODEV;
goto fail_release_rx;
}
return 0;
fail_release_rx:
dma_release_channel(espi->dma_rx);
espi->dma_rx = NULL;
fail_free_page:
free_page((unsigned long)espi->zeropage);
return ret;
}
static void ep93xx_spi_release_dma(struct ep93xx_spi *espi)
{
if (espi->dma_rx) {
dma_release_channel(espi->dma_rx);
sg_free_table(&espi->rx_sgt);
}
if (espi->dma_tx) {
dma_release_channel(espi->dma_tx);
sg_free_table(&espi->tx_sgt);
}
if (espi->zeropage)
free_page((unsigned long)espi->zeropage);
}
static int ep93xx_spi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct ep93xx_spi_info *info;
struct ep93xx_spi *espi;
struct resource *res;
int irq;
int error;
info = dev_get_platdata(&pdev->dev);
if (!info) {
dev_err(&pdev->dev, "missing platform data\n");
return -EINVAL;
}
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "failed to get irq resources\n");
return -EBUSY;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "unable to get iomem resource\n");
return -ENODEV;
}
master = spi_alloc_master(&pdev->dev, sizeof(*espi));
if (!master)
return -ENOMEM;
master->use_gpio_descriptors = true;
master->prepare_transfer_hardware = ep93xx_spi_prepare_hardware;
master->unprepare_transfer_hardware = ep93xx_spi_unprepare_hardware;
master->prepare_message = ep93xx_spi_prepare_message;
master->transfer_one = ep93xx_spi_transfer_one;
master->bus_num = pdev->id;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
/*
* The SPI core will count the number of GPIO descriptors to figure
* out the number of chip selects available on the platform.
*/
master->num_chipselect = 0;
platform_set_drvdata(pdev, master);
espi = spi_master_get_devdata(master);
espi->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(espi->clk)) {
dev_err(&pdev->dev, "unable to get spi clock\n");
error = PTR_ERR(espi->clk);
goto fail_release_master;
}
/*
* Calculate maximum and minimum supported clock rates
* for the controller.
*/
master->max_speed_hz = clk_get_rate(espi->clk) / 2;
master->min_speed_hz = clk_get_rate(espi->clk) / (254 * 256);
espi->sspdr_phys = res->start + SSPDR;
espi->mmio = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(espi->mmio)) {
error = PTR_ERR(espi->mmio);
goto fail_release_master;
}
error = devm_request_irq(&pdev->dev, irq, ep93xx_spi_interrupt,
0, "ep93xx-spi", master);
if (error) {
dev_err(&pdev->dev, "failed to request irq\n");
goto fail_release_master;
}
if (info->use_dma && ep93xx_spi_setup_dma(espi))
dev_warn(&pdev->dev, "DMA setup failed. Falling back to PIO\n");
/* make sure that the hardware is disabled */
writel(0, espi->mmio + SSPCR1);
error = devm_spi_register_master(&pdev->dev, master);
if (error) {
dev_err(&pdev->dev, "failed to register SPI master\n");
goto fail_free_dma;
}
dev_info(&pdev->dev, "EP93xx SPI Controller at 0x%08lx irq %d\n",
(unsigned long)res->start, irq);
return 0;
fail_free_dma:
ep93xx_spi_release_dma(espi);
fail_release_master:
spi_master_put(master);
return error;
}
static int ep93xx_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct ep93xx_spi *espi = spi_master_get_devdata(master);
ep93xx_spi_release_dma(espi);
return 0;
}
static struct platform_driver ep93xx_spi_driver = {
.driver = {
.name = "ep93xx-spi",
},
.probe = ep93xx_spi_probe,
.remove = ep93xx_spi_remove,
};
module_platform_driver(ep93xx_spi_driver);
MODULE_DESCRIPTION("EP93xx SPI Controller driver");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ep93xx-spi");