diff options
Diffstat (limited to 'target/linux/generic-2.6/files/drivers')
| -rw-r--r-- | target/linux/generic-2.6/files/drivers/spi/spi_gpio.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/target/linux/generic-2.6/files/drivers/spi/spi_gpio.c b/target/linux/generic-2.6/files/drivers/spi/spi_gpio.c new file mode 100644 index 000000000..31048acc3 --- /dev/null +++ b/target/linux/generic-2.6/files/drivers/spi/spi_gpio.c @@ -0,0 +1,242 @@ +/* + * 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"); |