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/*
* Bitbanging SPI bus driver using GPIO API
*
* Copyright (c) 2008 Piotr Skamruk
* Copyright (c) 2008 Michael Buesch
*
* based on spi_s3c2410_gpio.c
* Copyright (c) 2006 Ben Dooks
* Copyright (c) 2006 Simtec Electronics
* and on i2c-gpio.c
* Copyright (C) 2007 Atmel Corporation
*
* 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/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include "linux/spi/spi_gpio.h" //XXX
#include <asm/gpio.h>
struct spi_gpio {
struct spi_bitbang bitbang;
struct spi_gpio_platform_data *info;
struct platform_device *pdev;
struct spi_board_info bi;
};
static inline struct spi_gpio *spidev_to_sg(struct spi_device *dev)
{
return dev->controller_data;
}
static inline void setsck(struct spi_device *dev, int val)
{
struct spi_gpio *sp = spidev_to_sg(dev);
gpio_set_value(sp->info->pin_clk, val ? 1 : 0);
}
static inline void setmosi(struct spi_device *dev, int val )
{
struct spi_gpio *sp = spidev_to_sg(dev);
gpio_set_value(sp->info->pin_mosi, val ? 1 : 0);
}
static inline u32 getmiso(struct spi_device *dev)
{
struct spi_gpio *sp = spidev_to_sg(dev);
return gpio_get_value(sp->info->pin_miso) ? 1 : 0;
}
static inline void do_spidelay(struct spi_device *dev, unsigned nsecs)
{
struct spi_gpio *sp = spidev_to_sg(dev);
if (!sp->info->no_spi_delay)
ndelay(nsecs);
}
#define spidelay(nsecs) do { \
/* Steal the spi_device pointer from our caller. \
* The bitbang-API should probably get fixed here... */ \
do_spidelay(spi, nsecs); \
} while (0)
#define EXPAND_BITBANG_TXRX
#include <linux/spi/spi_bitbang.h>
static u32 spi_gpio_txrx_mode0(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
}
static u32 spi_gpio_txrx_mode1(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
}
static u32 spi_gpio_txrx_mode2(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
}
static u32 spi_gpio_txrx_mode3(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
}
static void spi_gpio_chipselect(struct spi_device *dev, int on)
{
struct spi_gpio *sp = spidev_to_sg(dev);
if (sp->info->cs_activelow)
on = !on;
gpio_set_value(sp->info->pin_cs, on ? 1 : 0);
}
static int spi_gpio_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct spi_gpio_platform_data *pdata;
struct spi_gpio *sp;
struct spi_device *spidev;
int err;
pdata = pdev->dev.platform_data;
if (!pdata)
return -ENXIO;
err = -ENOMEM;
master = spi_alloc_master(&pdev->dev, sizeof(struct spi_gpio));
if (!master)
goto err_alloc_master;
sp = spi_master_get_devdata(master);
platform_set_drvdata(pdev, sp);
sp->info = pdata;
err = gpio_request(pdata->pin_clk, "spi_clock");
if (err)
goto err_request_clk;
err = gpio_request(pdata->pin_mosi, "spi_mosi");
if (err)
goto err_request_mosi;
err = gpio_request(pdata->pin_miso, "spi_miso");
if (err)
goto err_request_miso;
err = gpio_request(pdata->pin_cs, "spi_cs");
if (err)
goto err_request_cs;
sp->bitbang.master = spi_master_get(master);
sp->bitbang.master->bus_num = -1;
sp->bitbang.master->num_chipselect = 1;
sp->bitbang.chipselect = spi_gpio_chipselect;
sp->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_mode0;
sp->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_mode1;
sp->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_mode2;
sp->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_mode3;
gpio_direction_output(pdata->pin_clk, 0);
gpio_direction_output(pdata->pin_mosi, 0);
gpio_direction_output(pdata->pin_cs,
pdata->cs_activelow ? 1 : 0);
gpio_direction_input(pdata->pin_miso);
err = spi_bitbang_start(&sp->bitbang);
if (err)
goto err_no_bitbang;
err = pdata->boardinfo_setup(&sp->bi, master,
pdata->boardinfo_setup_data);
if (err)
goto err_bi_setup;
sp->bi.controller_data = sp;
spidev = spi_new_device(master, &sp->bi);
if (!spidev)
goto err_new_dev;
return 0;
err_new_dev:
err_bi_setup:
spi_bitbang_stop(&sp->bitbang);
err_no_bitbang:
spi_master_put(sp->bitbang.master);
gpio_free(pdata->pin_cs);
err_request_cs:
gpio_free(pdata->pin_miso);
err_request_miso:
gpio_free(pdata->pin_mosi);
err_request_mosi:
gpio_free(pdata->pin_clk);
err_request_clk:
kfree(master);
err_alloc_master:
return err;
}
static int __devexit spi_gpio_remove(struct platform_device *pdev)
{
struct spi_gpio *sp;
struct spi_gpio_platform_data *pdata;
pdata = pdev->dev.platform_data;
sp = platform_get_drvdata(pdev);
gpio_free(pdata->pin_clk);
gpio_free(pdata->pin_mosi);
gpio_free(pdata->pin_miso);
gpio_free(pdata->pin_cs);
spi_bitbang_stop(&sp->bitbang);
spi_master_put(sp->bitbang.master);
return 0;
}
static struct platform_driver spi_gpio_driver = {
.driver = {
.name = "spi-gpio",
.owner = THIS_MODULE,
},
.probe = spi_gpio_probe,
.remove = __devexit_p(spi_gpio_remove),
};
static int __init spi_gpio_init(void)
{
int err;
err = platform_driver_register(&spi_gpio_driver);
if (err)
printk(KERN_ERR "spi-gpio: register failed: %d\n", err);
return err;
}
module_init(spi_gpio_init);
static void __exit spi_gpio_exit(void)
{
platform_driver_unregister(&spi_gpio_driver);
}
module_exit(spi_gpio_exit);
MODULE_AUTHOR("Piot Skamruk <piotr.skamruk at gmail.com>");
MODULE_AUTHOR("Michael Buesch");
MODULE_DESCRIPTION("Platform independent GPIO bitbangling SPI driver");
MODULE_LICENSE("GPL v2");
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