+--- /dev/null
++++ b/include/linux/spi/spi_gpio.h
+@@ -0,0 +1,72 @@
++/*
++ * spi_gpio interface to platform code
++ *
++ * Copyright (c) 2008 Piotr Skamruk
++ *
++ * 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.
++ */
++#ifndef _LINUX_SPI_SPI_GPIO
++#define _LINUX_SPI_SPI_GPIO
++
++#include <linux/types.h>
++#include <linux/spi/spi.h>
++
++
++/**
++ * struct spi_gpio_platform_data - Data definitions for a SPI-GPIO device.
++ *
++ * This structure holds information about a GPIO-based SPI device.
++ *
++ * @pin_clk: The GPIO pin number of the CLOCK pin.
++ *
++ * @pin_miso: The GPIO pin number of the MISO pin.
++ *
++ * @pin_mosi: The GPIO pin number of the MOSI pin.
++ *
++ * @pin_cs: The GPIO pin number of the CHIPSELECT pin.
++ *
++ * @cs_activelow: If true, the chip is selected when the CS line is low.
++ *
++ * @no_spi_delay: If true, no delay is done in the lowlevel bitbanging.
++ * Note that doing no delay is not standards compliant,
++ * but it might be needed to speed up transfers on some
++ * slow embedded machines.
++ *
++ * @boardinfo_setup: This callback is called after the
++ * SPI master device was registered, but before the
++ * device is registered.
++ * @boardinfo_setup_data: Data argument passed to boardinfo_setup().
++ */
++struct spi_gpio_platform_data {
++ unsigned int pin_clk;
++ unsigned int pin_miso;
++ unsigned int pin_mosi;
++ unsigned int pin_cs;
++ bool cs_activelow;
++ bool no_spi_delay;
++ int (*boardinfo_setup)(struct spi_board_info *bi,
++ struct spi_master *master,
++ void *data);
++ void *boardinfo_setup_data;
++};
++
++/**
++ * SPI_GPIO_PLATDEV_NAME - The platform device name string.
++ *
++ * The name string that has to be used for platform_device_alloc
++ * when allocating a spi-gpio device.
++ */
++#define SPI_GPIO_PLATDEV_NAME "spi-gpio"
++
++/**
++ * spi_gpio_next_id - Get another platform device ID number.
++ *
++ * This returns the next platform device ID number that has to be used
++ * for platform_device_alloc. The ID is opaque and should not be used for
++ * anything else.
++ */
++int spi_gpio_next_id(void);
++
++#endif /* _LINUX_SPI_SPI_GPIO */
+--- /dev/null
++++ b/drivers/spi/spi_gpio.c
+@@ -0,0 +1,249 @@
++/*
++ * Bitbanging SPI bus driver using GPIO API
++ *
++ * Copyright (c) 2008 Piotr Skamruk
++ *
++ * 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>
++#include <linux/gpio.h>
++#include <asm/atomic.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_PLATDEV_NAME,
++ .owner = THIS_MODULE,
++ },
++ .probe = spi_gpio_probe,
++ .remove = __devexit_p(spi_gpio_remove),
++};
++
++int spi_gpio_next_id(void)
++{
++ static atomic_t counter = ATOMIC_INIT(-1);
++
++ return atomic_inc_return(&counter);
++}
++EXPORT_SYMBOL(spi_gpio_next_id);
++
++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_DESCRIPTION("Platform independent GPIO bitbanging SPI driver");
++MODULE_LICENSE("GPL v2");
+--- a/drivers/spi/Kconfig
++++ b/drivers/spi/Kconfig
+@@ -100,6 +100,19 @@ config SPI_BUTTERFLY
projects / openwrt.git / blobdiff