linux/drivers/spi/spi_s3c24xx.c
Ben Dooks 570327d9f4 spi_s3c24xx: cache device setup data
With the update to the spi_bitbang driver, the transfer setup code is
being called more often, and thus is often re-doing calculations that have
been done before.  The SPI layer allows our driver to add its own data to
each device so add a result cache to each device.

This should also remove the problem where we where directly setting up
registers in the setup call which meant we might overwrite the state of an
extant transfer.,

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23 07:39:44 -07:00

527 lines
11 KiB
C

/* linux/drivers/spi/spi_s3c24xx.c
*
* Copyright (c) 2006 Ben Dooks
* Copyright (c) 2006 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* 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/init.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <plat/regs-spi.h>
#include <mach/spi.h>
/**
* s3c24xx_spi_devstate - per device data
* @hz: Last frequency calculated for @sppre field.
* @mode: Last mode setting for the @spcon field.
* @spcon: Value to write to the SPCON register.
* @sppre: Value to write to the SPPRE register.
*/
struct s3c24xx_spi_devstate {
unsigned int hz;
unsigned int mode;
u8 spcon;
u8 sppre;
};
struct s3c24xx_spi {
/* bitbang has to be first */
struct spi_bitbang bitbang;
struct completion done;
void __iomem *regs;
int irq;
int len;
int count;
void (*set_cs)(struct s3c2410_spi_info *spi,
int cs, int pol);
/* data buffers */
const unsigned char *tx;
unsigned char *rx;
struct clk *clk;
struct resource *ioarea;
struct spi_master *master;
struct spi_device *curdev;
struct device *dev;
struct s3c2410_spi_info *pdata;
};
#define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
#define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
{
return spi_master_get_devdata(sdev->master);
}
static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol)
{
gpio_set_value(spi->pin_cs, pol);
}
static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
{
struct s3c24xx_spi_devstate *cs = spi->controller_state;
struct s3c24xx_spi *hw = to_hw(spi);
unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
/* change the chipselect state and the state of the spi engine clock */
switch (value) {
case BITBANG_CS_INACTIVE:
hw->set_cs(hw->pdata, spi->chip_select, cspol^1);
writeb(cs->spcon, hw->regs + S3C2410_SPCON);
break;
case BITBANG_CS_ACTIVE:
writeb(cs->spcon | S3C2410_SPCON_ENSCK,
hw->regs + S3C2410_SPCON);
hw->set_cs(hw->pdata, spi->chip_select, cspol);
break;
}
}
static int s3c24xx_spi_update_state(struct spi_device *spi,
struct spi_transfer *t)
{
struct s3c24xx_spi *hw = to_hw(spi);
struct s3c24xx_spi_devstate *cs = spi->controller_state;
unsigned int bpw;
unsigned int hz;
unsigned int div;
unsigned long clk;
bpw = t ? t->bits_per_word : spi->bits_per_word;
hz = t ? t->speed_hz : spi->max_speed_hz;
if (!bpw)
bpw = 8;
if (!hz)
hz = spi->max_speed_hz;
if (bpw != 8) {
dev_err(&spi->dev, "invalid bits-per-word (%d)\n", bpw);
return -EINVAL;
}
if (spi->mode != cs->mode) {
u8 spcon = SPCON_DEFAULT;
if (spi->mode & SPI_CPHA)
spcon |= S3C2410_SPCON_CPHA_FMTB;
if (spi->mode & SPI_CPOL)
spcon |= S3C2410_SPCON_CPOL_HIGH;
cs->mode = spi->mode;
cs->spcon = spcon;
}
if (cs->hz != hz) {
clk = clk_get_rate(hw->clk);
div = DIV_ROUND_UP(clk, hz * 2) - 1;
if (div > 255)
div = 255;
dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n",
div, hz, clk / (2 * (div + 1)));
cs->hz = hz;
cs->sppre = div;
}
return 0;
}
static int s3c24xx_spi_setupxfer(struct spi_device *spi,
struct spi_transfer *t)
{
struct s3c24xx_spi_devstate *cs = spi->controller_state;
struct s3c24xx_spi *hw = to_hw(spi);
int ret;
ret = s3c24xx_spi_update_state(spi, t);
if (!ret)
writeb(cs->sppre, hw->regs + S3C2410_SPPRE);
return ret;
}
static int s3c24xx_spi_setup(struct spi_device *spi)
{
struct s3c24xx_spi_devstate *cs = spi->controller_state;
struct s3c24xx_spi *hw = to_hw(spi);
int ret;
/* allocate settings on the first call */
if (!cs) {
cs = kzalloc(sizeof(struct s3c24xx_spi_devstate), GFP_KERNEL);
if (!cs) {
dev_err(&spi->dev, "no memory for controller state\n");
return -ENOMEM;
}
cs->spcon = SPCON_DEFAULT;
cs->hz = -1;
spi->controller_state = cs;
}
/* initialise the state from the device */
ret = s3c24xx_spi_update_state(spi, NULL);
if (ret)
return ret;
spin_lock(&hw->bitbang.lock);
if (!hw->bitbang.busy) {
hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
/* need to ndelay for 0.5 clocktick ? */
}
spin_unlock(&hw->bitbang.lock);
return 0;
}
static void s3c24xx_spi_cleanup(struct spi_device *spi)
{
kfree(spi->controller_state);
}
static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
{
return hw->tx ? hw->tx[count] : 0;
}
static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
{
struct s3c24xx_spi *hw = to_hw(spi);
dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
t->tx_buf, t->rx_buf, t->len);
hw->tx = t->tx_buf;
hw->rx = t->rx_buf;
hw->len = t->len;
hw->count = 0;
init_completion(&hw->done);
/* send the first byte */
writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
wait_for_completion(&hw->done);
return hw->count;
}
static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
{
struct s3c24xx_spi *hw = dev;
unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
unsigned int count = hw->count;
if (spsta & S3C2410_SPSTA_DCOL) {
dev_dbg(hw->dev, "data-collision\n");
complete(&hw->done);
goto irq_done;
}
if (!(spsta & S3C2410_SPSTA_READY)) {
dev_dbg(hw->dev, "spi not ready for tx?\n");
complete(&hw->done);
goto irq_done;
}
hw->count++;
if (hw->rx)
hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
count++;
if (count < hw->len)
writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
else
complete(&hw->done);
irq_done:
return IRQ_HANDLED;
}
static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
{
/* for the moment, permanently enable the clock */
clk_enable(hw->clk);
/* program defaults into the registers */
writeb(0xff, hw->regs + S3C2410_SPPRE);
writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
if (hw->pdata) {
if (hw->set_cs == s3c24xx_spi_gpiocs)
gpio_direction_output(hw->pdata->pin_cs, 1);
if (hw->pdata->gpio_setup)
hw->pdata->gpio_setup(hw->pdata, 1);
}
}
static int __init s3c24xx_spi_probe(struct platform_device *pdev)
{
struct s3c2410_spi_info *pdata;
struct s3c24xx_spi *hw;
struct spi_master *master;
struct resource *res;
int err = 0;
master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
if (master == NULL) {
dev_err(&pdev->dev, "No memory for spi_master\n");
err = -ENOMEM;
goto err_nomem;
}
hw = spi_master_get_devdata(master);
memset(hw, 0, sizeof(struct s3c24xx_spi));
hw->master = spi_master_get(master);
hw->pdata = pdata = pdev->dev.platform_data;
hw->dev = &pdev->dev;
if (pdata == NULL) {
dev_err(&pdev->dev, "No platform data supplied\n");
err = -ENOENT;
goto err_no_pdata;
}
platform_set_drvdata(pdev, hw);
init_completion(&hw->done);
/* setup the master state. */
/* the spi->mode bits understood by this driver: */
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->num_chipselect = hw->pdata->num_cs;
master->bus_num = pdata->bus_num;
/* setup the state for the bitbang driver */
hw->bitbang.master = hw->master;
hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
hw->bitbang.chipselect = s3c24xx_spi_chipsel;
hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
hw->master->setup = s3c24xx_spi_setup;
hw->master->cleanup = s3c24xx_spi_cleanup;
dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
/* find and map our resources */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
err = -ENOENT;
goto err_no_iores;
}
hw->ioarea = request_mem_region(res->start, resource_size(res),
pdev->name);
if (hw->ioarea == NULL) {
dev_err(&pdev->dev, "Cannot reserve region\n");
err = -ENXIO;
goto err_no_iores;
}
hw->regs = ioremap(res->start, resource_size(res));
if (hw->regs == NULL) {
dev_err(&pdev->dev, "Cannot map IO\n");
err = -ENXIO;
goto err_no_iomap;
}
hw->irq = platform_get_irq(pdev, 0);
if (hw->irq < 0) {
dev_err(&pdev->dev, "No IRQ specified\n");
err = -ENOENT;
goto err_no_irq;
}
err = request_irq(hw->irq, s3c24xx_spi_irq, 0, pdev->name, hw);
if (err) {
dev_err(&pdev->dev, "Cannot claim IRQ\n");
goto err_no_irq;
}
hw->clk = clk_get(&pdev->dev, "spi");
if (IS_ERR(hw->clk)) {
dev_err(&pdev->dev, "No clock for device\n");
err = PTR_ERR(hw->clk);
goto err_no_clk;
}
/* setup any gpio we can */
if (!pdata->set_cs) {
if (pdata->pin_cs < 0) {
dev_err(&pdev->dev, "No chipselect pin\n");
goto err_register;
}
err = gpio_request(pdata->pin_cs, dev_name(&pdev->dev));
if (err) {
dev_err(&pdev->dev, "Failed to get gpio for cs\n");
goto err_register;
}
hw->set_cs = s3c24xx_spi_gpiocs;
gpio_direction_output(pdata->pin_cs, 1);
} else
hw->set_cs = pdata->set_cs;
s3c24xx_spi_initialsetup(hw);
/* register our spi controller */
err = spi_bitbang_start(&hw->bitbang);
if (err) {
dev_err(&pdev->dev, "Failed to register SPI master\n");
goto err_register;
}
return 0;
err_register:
if (hw->set_cs == s3c24xx_spi_gpiocs)
gpio_free(pdata->pin_cs);
clk_disable(hw->clk);
clk_put(hw->clk);
err_no_clk:
free_irq(hw->irq, hw);
err_no_irq:
iounmap(hw->regs);
err_no_iomap:
release_resource(hw->ioarea);
kfree(hw->ioarea);
err_no_iores:
err_no_pdata:
spi_master_put(hw->master);
err_nomem:
return err;
}
static int __exit s3c24xx_spi_remove(struct platform_device *dev)
{
struct s3c24xx_spi *hw = platform_get_drvdata(dev);
platform_set_drvdata(dev, NULL);
spi_unregister_master(hw->master);
clk_disable(hw->clk);
clk_put(hw->clk);
free_irq(hw->irq, hw);
iounmap(hw->regs);
if (hw->set_cs == s3c24xx_spi_gpiocs)
gpio_free(hw->pdata->pin_cs);
release_resource(hw->ioarea);
kfree(hw->ioarea);
spi_master_put(hw->master);
return 0;
}
#ifdef CONFIG_PM
static int s3c24xx_spi_suspend(struct device *dev)
{
struct s3c24xx_spi *hw = platform_get_drvdata(to_platform_device(dev));
if (hw->pdata && hw->pdata->gpio_setup)
hw->pdata->gpio_setup(hw->pdata, 0);
clk_disable(hw->clk);
return 0;
}
static int s3c24xx_spi_resume(struct device *dev)
{
struct s3c24xx_spi *hw = platform_get_drvdata(to_platform_device(dev));
s3c24xx_spi_initialsetup(hw);
return 0;
}
static struct dev_pm_ops s3c24xx_spi_pmops = {
.suspend = s3c24xx_spi_suspend,
.resume = s3c24xx_spi_resume,
};
#define S3C24XX_SPI_PMOPS &s3c24xx_spi_pmops
#else
#define S3C24XX_SPI_PMOPS NULL
#endif /* CONFIG_PM */
MODULE_ALIAS("platform:s3c2410-spi");
static struct platform_driver s3c24xx_spi_driver = {
.remove = __exit_p(s3c24xx_spi_remove),
.driver = {
.name = "s3c2410-spi",
.owner = THIS_MODULE,
.pm = S3C24XX_SPI_PMOPS,
},
};
static int __init s3c24xx_spi_init(void)
{
return platform_driver_probe(&s3c24xx_spi_driver, s3c24xx_spi_probe);
}
static void __exit s3c24xx_spi_exit(void)
{
platform_driver_unregister(&s3c24xx_spi_driver);
}
module_init(s3c24xx_spi_init);
module_exit(s3c24xx_spi_exit);
MODULE_DESCRIPTION("S3C24XX SPI Driver");
MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");