| /* |
| * 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_old.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 "spi-bitbang-txrx.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, 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, 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, 0, 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, 0, 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_AUTHOR("Michael Buesch"); |
| MODULE_DESCRIPTION("Platform independent GPIO bitbanging SPI driver"); |
| MODULE_LICENSE("GPL v2"); |