linux/drivers/spi/spi_s3c24xx_gpio.c
Marek Szyprowski 04bb2a031c spi/bitbang: add support for SPI_MASTER_NO_{TX, RX} modes
This patch adds a new flags argument to bitbang_txrx_be_cpha0 and
bitbang_txrx_be_cpha1 transfer functions. This enables support for
SPI_MASTER_NO_{TX,RX} transfer modes. The change should have no impact
on speed of the existing drivers. bitbank_txrx_* functions are usually
inlined into the drivers. When the argument is equal to constant zero,
the optimizer would be able to eliminate the dead code (flags checks)
easily. Tested on ARM and GCC 4.4.x and in all cases the checks were
eliminated in the inlined function.

Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-03 22:45:44 -06:00

201 lines
5.1 KiB
C

/* linux/drivers/spi/spi_s3c24xx_gpio.c
*
* Copyright (c) 2006 Ben Dooks
* Copyright (c) 2006 Simtec Electronics
*
* S3C24XX GPIO based SPI driver
*
* 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/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <mach/regs-gpio.h>
#include <mach/spi-gpio.h>
#include <mach/hardware.h>
struct s3c2410_spigpio {
struct spi_bitbang bitbang;
struct s3c2410_spigpio_info *info;
struct platform_device *dev;
};
static inline struct s3c2410_spigpio *spidev_to_sg(struct spi_device *spi)
{
return spi_master_get_devdata(spi->master);
}
static inline void setsck(struct spi_device *dev, int on)
{
struct s3c2410_spigpio *sg = spidev_to_sg(dev);
s3c2410_gpio_setpin(sg->info->pin_clk, on ? 1 : 0);
}
static inline void setmosi(struct spi_device *dev, int on)
{
struct s3c2410_spigpio *sg = spidev_to_sg(dev);
s3c2410_gpio_setpin(sg->info->pin_mosi, on ? 1 : 0);
}
static inline u32 getmiso(struct spi_device *dev)
{
struct s3c2410_spigpio *sg = spidev_to_sg(dev);
return s3c2410_gpio_getpin(sg->info->pin_miso) ? 1 : 0;
}
#define spidelay(x) ndelay(x)
#include "spi_bitbang_txrx.h"
static u32 s3c2410_spigpio_txrx_mode0(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
}
static u32 s3c2410_spigpio_txrx_mode1(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
}
static u32 s3c2410_spigpio_txrx_mode2(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
}
static u32 s3c2410_spigpio_txrx_mode3(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
}
static void s3c2410_spigpio_chipselect(struct spi_device *dev, int value)
{
struct s3c2410_spigpio *sg = spidev_to_sg(dev);
if (sg->info && sg->info->chip_select)
(sg->info->chip_select)(sg->info, value);
}
static int s3c2410_spigpio_probe(struct platform_device *dev)
{
struct s3c2410_spigpio_info *info;
struct spi_master *master;
struct s3c2410_spigpio *sp;
int ret;
master = spi_alloc_master(&dev->dev, sizeof(struct s3c2410_spigpio));
if (master == NULL) {
dev_err(&dev->dev, "failed to allocate spi master\n");
ret = -ENOMEM;
goto err;
}
sp = spi_master_get_devdata(master);
platform_set_drvdata(dev, sp);
/* copy in the plkatform data */
info = sp->info = dev->dev.platform_data;
/* setup spi bitbang adaptor */
sp->bitbang.master = spi_master_get(master);
sp->bitbang.master->bus_num = info->bus_num;
sp->bitbang.master->num_chipselect = info->num_chipselect;
sp->bitbang.chipselect = s3c2410_spigpio_chipselect;
sp->bitbang.txrx_word[SPI_MODE_0] = s3c2410_spigpio_txrx_mode0;
sp->bitbang.txrx_word[SPI_MODE_1] = s3c2410_spigpio_txrx_mode1;
sp->bitbang.txrx_word[SPI_MODE_2] = s3c2410_spigpio_txrx_mode2;
sp->bitbang.txrx_word[SPI_MODE_3] = s3c2410_spigpio_txrx_mode3;
/* set state of spi pins, always assume that the clock is
* available, but do check the MOSI and MISO. */
s3c2410_gpio_setpin(info->pin_clk, 0);
s3c2410_gpio_cfgpin(info->pin_clk, S3C2410_GPIO_OUTPUT);
if (info->pin_mosi < S3C2410_GPH10) {
s3c2410_gpio_setpin(info->pin_mosi, 0);
s3c2410_gpio_cfgpin(info->pin_mosi, S3C2410_GPIO_OUTPUT);
}
if (info->pin_miso != S3C2410_GPA0 && info->pin_miso < S3C2410_GPH10)
s3c2410_gpio_cfgpin(info->pin_miso, S3C2410_GPIO_INPUT);
ret = spi_bitbang_start(&sp->bitbang);
if (ret)
goto err_no_bitbang;
return 0;
err_no_bitbang:
spi_master_put(sp->bitbang.master);
err:
return ret;
}
static int s3c2410_spigpio_remove(struct platform_device *dev)
{
struct s3c2410_spigpio *sp = platform_get_drvdata(dev);
spi_bitbang_stop(&sp->bitbang);
spi_master_put(sp->bitbang.master);
return 0;
}
/* all gpio should be held over suspend/resume, so we should
* not need to deal with this
*/
#define s3c2410_spigpio_suspend NULL
#define s3c2410_spigpio_resume NULL
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:spi_s3c24xx_gpio");
static struct platform_driver s3c2410_spigpio_drv = {
.probe = s3c2410_spigpio_probe,
.remove = s3c2410_spigpio_remove,
.suspend = s3c2410_spigpio_suspend,
.resume = s3c2410_spigpio_resume,
.driver = {
.name = "spi_s3c24xx_gpio",
.owner = THIS_MODULE,
},
};
static int __init s3c2410_spigpio_init(void)
{
return platform_driver_register(&s3c2410_spigpio_drv);
}
static void __exit s3c2410_spigpio_exit(void)
{
platform_driver_unregister(&s3c2410_spigpio_drv);
}
module_init(s3c2410_spigpio_init);
module_exit(s3c2410_spigpio_exit);
MODULE_DESCRIPTION("S3C24XX SPI Driver");
MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");