kernel-ark/drivers/spi/spi_s3c24xx.c
David Brownell d1e44d9ce8 SPI driver runtime footprint shrinkage
Shrink the runtime footprint of various SPI drivers:

  - Move the probe() routine into the init section where practical,
    using platform_driver_probe() to make that safe.  This often saves
    around 1KB.  Using platform_driver_probe() can also be a correctness
    fix, if the probe routine is already marked __init but the driver
    struct keeps a dangling pointer to it after init section removal.

  - Likewise move remove() routines into the exit sections.

These changes would be inappropriate iff the platform devices were
actually hotpluggable (e.g. they're found on optional addon cards,
or in an FPGA that's dynamically reprogrammed).  In these cases,
that's not the situation; it's an SOC controller and the only device
is initialized before these drivers.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:43:09 -07:00

457 lines
9.7 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/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/hardware.h>
#include <asm/arch/regs-gpio.h>
#include <asm/plat-s3c24xx/regs-spi.h>
#include <asm/arch/spi.h>
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)
{
s3c2410_gpio_setpin(spi->pin_cs, pol);
}
static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
{
struct s3c24xx_spi *hw = to_hw(spi);
unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
unsigned int spcon;
switch (value) {
case BITBANG_CS_INACTIVE:
hw->set_cs(hw->pdata, spi->chip_select, cspol^1);
break;
case BITBANG_CS_ACTIVE:
spcon = readb(hw->regs + S3C2410_SPCON);
if (spi->mode & SPI_CPHA)
spcon |= S3C2410_SPCON_CPHA_FMTB;
else
spcon &= ~S3C2410_SPCON_CPHA_FMTB;
if (spi->mode & SPI_CPOL)
spcon |= S3C2410_SPCON_CPOL_HIGH;
else
spcon &= ~S3C2410_SPCON_CPOL_HIGH;
spcon |= S3C2410_SPCON_ENSCK;
/* write new configration */
writeb(spcon, hw->regs + S3C2410_SPCON);
hw->set_cs(hw->pdata, spi->chip_select, cspol);
break;
}
}
static int s3c24xx_spi_setupxfer(struct spi_device *spi,
struct spi_transfer *t)
{
struct s3c24xx_spi *hw = to_hw(spi);
unsigned int bpw;
unsigned int hz;
unsigned int div;
bpw = t ? t->bits_per_word : spi->bits_per_word;
hz = t ? t->speed_hz : spi->max_speed_hz;
if (bpw != 8) {
dev_err(&spi->dev, "invalid bits-per-word (%d)\n", bpw);
return -EINVAL;
}
div = clk_get_rate(hw->clk) / hz;
/* is clk = pclk / (2 * (pre+1)), or is it
* clk = (pclk * 2) / ( pre + 1) */
div = (div / 2) - 1;
if (div < 0)
div = 1;
if (div > 255)
div = 255;
dev_dbg(&spi->dev, "setting pre-scaler to %d (hz %d)\n", div, hz);
writeb(div, hw->regs + S3C2410_SPPRE);
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;
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
static int s3c24xx_spi_setup(struct spi_device *spi)
{
int ret;
if (!spi->bits_per_word)
spi->bits_per_word = 8;
if (spi->mode & ~MODEBITS) {
dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
spi->mode & ~MODEBITS);
return -EINVAL;
}
ret = s3c24xx_spi_setupxfer(spi, NULL);
if (ret < 0) {
dev_err(&spi->dev, "setupxfer returned %d\n", ret);
return ret;
}
dev_dbg(&spi->dev, "%s: mode %d, %u bpw, %d hz\n",
__FUNCTION__, spi->mode, spi->bits_per_word,
spi->max_speed_hz);
return 0;
}
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;
/* 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 int __init s3c24xx_spi_probe(struct platform_device *pdev)
{
struct s3c24xx_spi *hw;
struct spi_master *master;
struct spi_board_info *bi;
struct resource *res;
int err = 0;
int i;
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 = pdev->dev.platform_data;
hw->dev = &pdev->dev;
if (hw->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 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->bitbang.master->setup = s3c24xx_spi_setup;
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, (res->end - res->start)+1,
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, (res->end - res->start)+1);
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;
}
/* 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);
/* setup any gpio we can */
if (!hw->pdata->set_cs) {
hw->set_cs = s3c24xx_spi_gpiocs;
s3c2410_gpio_setpin(hw->pdata->pin_cs, 1);
s3c2410_gpio_cfgpin(hw->pdata->pin_cs, S3C2410_GPIO_OUTPUT);
} else
hw->set_cs = hw->pdata->set_cs;
/* 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;
}
/* register all the devices associated */
bi = &hw->pdata->board_info[0];
for (i = 0; i < hw->pdata->board_size; i++, bi++) {
dev_info(hw->dev, "registering %s\n", bi->modalias);
bi->controller_data = hw;
spi_new_device(master, bi);
}
return 0;
err_register:
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);
release_resource(hw->ioarea);
kfree(hw->ioarea);
spi_master_put(hw->master);
return 0;
}
#ifdef CONFIG_PM
static int s3c24xx_spi_suspend(struct platform_device *pdev, pm_message_t msg)
{
struct s3c24xx_spi *hw = platform_get_drvdata(pdev);
clk_disable(hw->clk);
return 0;
}
static int s3c24xx_spi_resume(struct platform_device *pdev)
{
struct s3c24xx_spi *hw = platform_get_drvdata(pdev);
clk_enable(hw->clk);
return 0;
}
#else
#define s3c24xx_spi_suspend NULL
#define s3c24xx_spi_resume NULL
#endif
MODULE_ALIAS("s3c2410_spi"); /* for platform bus hotplug */
static struct platform_driver s3c24xx_spidrv = {
.remove = __exit_p(s3c24xx_spi_remove),
.suspend = s3c24xx_spi_suspend,
.resume = s3c24xx_spi_resume,
.driver = {
.name = "s3c2410-spi",
.owner = THIS_MODULE,
},
};
static int __init s3c24xx_spi_init(void)
{
return platform_driver_probe(&s3c24xx_spidrv, s3c24xx_spi_probe);
}
static void __exit s3c24xx_spi_exit(void)
{
platform_driver_unregister(&s3c24xx_spidrv);
}
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");