target/linux/generic/patches-2.6.25/921-gpio_spi_driver.patch

   1 --- /dev/null
   2 +++ b/include/linux/spi/spi_gpio.h
   3 @@ -0,0 +1,72 @@
   4 +/*
   5 + * spi_gpio interface to platform code
   6 + *
   7 + * Copyright (c) 2008 Piotr Skamruk
   8 + *
   9 + * This program is free software; you can redistribute it and/or modify
  10 + * it under the terms of the GNU General Public License version 2 as
  11 + * published by the Free Software Foundation.
  12 + */
  13 +#ifndef _LINUX_SPI_SPI_GPIO
  14 +#define _LINUX_SPI_SPI_GPIO
  15 +
  16 +#include <linux/types.h>
  17 +#include <linux/spi/spi.h>
  18 +
  19 +
  20 +/**
  21 + * struct spi_gpio_platform_data - Data definitions for a SPI-GPIO device.
  22 + *
  23 + * This structure holds information about a GPIO-based SPI device.
  24 + *
  25 + * @pin_clk: The GPIO pin number of the CLOCK pin.
  26 + *
  27 + * @pin_miso: The GPIO pin number of the MISO pin.
  28 + *
  29 + * @pin_mosi: The GPIO pin number of the MOSI pin.
  30 + *
  31 + * @pin_cs: The GPIO pin number of the CHIPSELECT pin.
  32 + *
  33 + * @cs_activelow: If true, the chip is selected when the CS line is low.
  34 + *
  35 + * @no_spi_delay: If true, no delay is done in the lowlevel bitbanging.
  36 + *                Note that doing no delay is not standards compliant,
  37 + *                but it might be needed to speed up transfers on some
  38 + *                slow embedded machines.
  39 + *
  40 + * @boardinfo_setup: This callback is called after the
  41 + *                   SPI master device was registered, but before the
  42 + *                   device is registered.
  43 + * @boardinfo_setup_data: Data argument passed to boardinfo_setup().
  44 + */
  45 +struct spi_gpio_platform_data {
  46 +       unsigned int pin_clk;
  47 +       unsigned int pin_miso;
  48 +       unsigned int pin_mosi;
  49 +       unsigned int pin_cs;
  50 +       bool cs_activelow;
  51 +       bool no_spi_delay;
  52 +       int (*boardinfo_setup)(struct spi_board_info *bi,
  53 +                              struct spi_master *master,
  54 +                              void *data);
  55 +       void *boardinfo_setup_data;
  56 +};
  57 +
  58 +/**
  59 + * SPI_GPIO_PLATDEV_NAME - The platform device name string.
  60 + *
  61 + * The name string that has to be used for platform_device_alloc
  62 + * when allocating a spi-gpio device.
  63 + */
  64 +#define SPI_GPIO_PLATDEV_NAME  "spi-gpio"
  65 +
  66 +/**
  67 + * spi_gpio_next_id - Get another platform device ID number.
  68 + *
  69 + * This returns the next platform device ID number that has to be used
  70 + * for platform_device_alloc. The ID is opaque and should not be used for
  71 + * anything else.
  72 + */
  73 +int spi_gpio_next_id(void);
  74 +
  75 +#endif /* _LINUX_SPI_SPI_GPIO */
  76 --- /dev/null
  77 +++ b/drivers/spi/spi_gpio.c
  78 @@ -0,0 +1,249 @@
  79 +/*
  80 + * Bitbanging SPI bus driver using GPIO API
  81 + *
  82 + * Copyright (c) 2008 Piotr Skamruk
  83 + *
  84 + * based on spi_s3c2410_gpio.c
  85 + *   Copyright (c) 2006 Ben Dooks
  86 + *   Copyright (c) 2006 Simtec Electronics
  87 + * and on i2c-gpio.c
  88 + *   Copyright (C) 2007 Atmel Corporation
  89 + *
  90 + * This program is free software; you can redistribute it and/or modify
  91 + * it under the terms of the GNU General Public License version 2 as
  92 + * published by the Free Software Foundation.
  93 + */
  94 +
  95 +#include <linux/kernel.h>
  96 +#include <linux/init.h>
  97 +#include <linux/delay.h>
  98 +#include <linux/spinlock.h>
  99 +#include <linux/workqueue.h>
 100 +#include <linux/module.h>
 101 +#include <linux/platform_device.h>
 102 +#include <linux/spi/spi.h>
 103 +#include <linux/spi/spi_bitbang.h>
 104 +#include <linux/spi/spi_gpio.h>
 105 +#include <linux/gpio.h>
 106 +#include <asm/atomic.h>
 107 +
 108 +
 109 +struct spi_gpio {
 110 +       struct spi_bitbang bitbang;
 111 +       struct spi_gpio_platform_data *info;
 112 +       struct platform_device *pdev;
 113 +       struct spi_board_info bi;
 114 +};
 115 +
 116 +
 117 +static inline struct spi_gpio *spidev_to_sg(struct spi_device *dev)
 118 +{
 119 +       return dev->controller_data;
 120 +}
 121 +
 122 +static inline void setsck(struct spi_device *dev, int val)
 123 +{
 124 +       struct spi_gpio *sp = spidev_to_sg(dev);
 125 +       gpio_set_value(sp->info->pin_clk, val ? 1 : 0);
 126 +}
 127 +
 128 +static inline void setmosi(struct spi_device *dev, int val)
 129 +{
 130 +       struct spi_gpio *sp = spidev_to_sg(dev);
 131 +       gpio_set_value(sp->info->pin_mosi, val ? 1 : 0);
 132 +}
 133 +
 134 +static inline u32 getmiso(struct spi_device *dev)
 135 +{
 136 +       struct spi_gpio *sp = spidev_to_sg(dev);
 137 +       return gpio_get_value(sp->info->pin_miso) ? 1 : 0;
 138 +}
 139 +
 140 +static inline void do_spidelay(struct spi_device *dev, unsigned nsecs)
 141 +{
 142 +       struct spi_gpio *sp = spidev_to_sg(dev);
 143 +
 144 +       if (!sp->info->no_spi_delay)
 145 +               ndelay(nsecs);
 146 +}
 147 +
 148 +#define spidelay(nsecs) do {                                   \
 149 +       /* Steal the spi_device pointer from our caller.        \
 150 +        * The bitbang-API should probably get fixed here... */ \
 151 +       do_spidelay(spi, nsecs);                                \
 152 +  } while (0)
 153 +
 154 +#define EXPAND_BITBANG_TXRX
 155 +#include <linux/spi/spi_bitbang.h>
 156 +
 157 +static u32 spi_gpio_txrx_mode0(struct spi_device *spi,
 158 +                              unsigned nsecs, u32 word, u8 bits)
 159 +{
 160 +       return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
 161 +}
 162 +
 163 +static u32 spi_gpio_txrx_mode1(struct spi_device *spi,
 164 +                              unsigned nsecs, u32 word, u8 bits)
 165 +{
 166 +       return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
 167 +}
 168 +
 169 +static u32 spi_gpio_txrx_mode2(struct spi_device *spi,
 170 +                              unsigned nsecs, u32 word, u8 bits)
 171 +{
 172 +       return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
 173 +}
 174 +
 175 +static u32 spi_gpio_txrx_mode3(struct spi_device *spi,
 176 +                              unsigned nsecs, u32 word, u8 bits)
 177 +{
 178 +       return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
 179 +}
 180 +
 181 +static void spi_gpio_chipselect(struct spi_device *dev, int on)
 182 +{
 183 +       struct spi_gpio *sp = spidev_to_sg(dev);
 184 +
 185 +       if (sp->info->cs_activelow)
 186 +               on = !on;
 187 +       gpio_set_value(sp->info->pin_cs, on ? 1 : 0);
 188 +}
 189 +
 190 +static int spi_gpio_probe(struct platform_device *pdev)
 191 +{
 192 +       struct spi_master *master;
 193 +       struct spi_gpio_platform_data *pdata;
 194 +       struct spi_gpio *sp;
 195 +       struct spi_device *spidev;
 196 +       int err;
 197 +
 198 +       pdata = pdev->dev.platform_data;
 199 +       if (!pdata)
 200 +               return -ENXIO;
 201 +
 202 +       err = -ENOMEM;
 203 +       master = spi_alloc_master(&pdev->dev, sizeof(struct spi_gpio));
 204 +       if (!master)
 205 +               goto err_alloc_master;
 206 +
 207 +       sp = spi_master_get_devdata(master);
 208 +       platform_set_drvdata(pdev, sp);
 209 +       sp->info = pdata;
 210 +
 211 +       err = gpio_request(pdata->pin_clk, "spi_clock");
 212 +       if (err)
 213 +               goto err_request_clk;
 214 +       err = gpio_request(pdata->pin_mosi, "spi_mosi");
 215 +       if (err)
 216 +               goto err_request_mosi;
 217 +       err = gpio_request(pdata->pin_miso, "spi_miso");
 218 +       if (err)
 219 +               goto err_request_miso;
 220 +       err = gpio_request(pdata->pin_cs, "spi_cs");
 221 +       if (err)
 222 +               goto err_request_cs;
 223 +
 224 +       sp->bitbang.master = spi_master_get(master);
 225 +       sp->bitbang.master->bus_num = -1;
 226 +       sp->bitbang.master->num_chipselect = 1;
 227 +       sp->bitbang.chipselect = spi_gpio_chipselect;
 228 +       sp->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_mode0;
 229 +       sp->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_mode1;
 230 +       sp->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_mode2;
 231 +       sp->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_mode3;
 232 +
 233 +       gpio_direction_output(pdata->pin_clk, 0);
 234 +       gpio_direction_output(pdata->pin_mosi, 0);
 235 +       gpio_direction_output(pdata->pin_cs,
 236 +                             pdata->cs_activelow ? 1 : 0);
 237 +       gpio_direction_input(pdata->pin_miso);
 238 +
 239 +       err = spi_bitbang_start(&sp->bitbang);
 240 +       if (err)
 241 +               goto err_no_bitbang;
 242 +       err = pdata->boardinfo_setup(&sp->bi, master,
 243 +                                    pdata->boardinfo_setup_data);
 244 +       if (err)
 245 +               goto err_bi_setup;
 246 +       sp->bi.controller_data = sp;
 247 +       spidev = spi_new_device(master, &sp->bi);
 248 +       if (!spidev)
 249 +               goto err_new_dev;
 250 +
 251 +       return 0;
 252 +
 253 +err_new_dev:
 254 +err_bi_setup:
 255 +       spi_bitbang_stop(&sp->bitbang);
 256 +err_no_bitbang:
 257 +       spi_master_put(sp->bitbang.master);
 258 +       gpio_free(pdata->pin_cs);
 259 +err_request_cs:
 260 +       gpio_free(pdata->pin_miso);
 261 +err_request_miso:
 262 +       gpio_free(pdata->pin_mosi);
 263 +err_request_mosi:
 264 +       gpio_free(pdata->pin_clk);
 265 +err_request_clk:
 266 +       kfree(master);
 267 +
 268 +err_alloc_master:
 269 +       return err;
 270 +}
 271 +
 272 +static int __devexit spi_gpio_remove(struct platform_device *pdev)
 273 +{
 274 +       struct spi_gpio *sp;
 275 +       struct spi_gpio_platform_data *pdata;
 276 +
 277 +       pdata = pdev->dev.platform_data;
 278 +       sp = platform_get_drvdata(pdev);
 279 +
 280 +       gpio_free(pdata->pin_clk);
 281 +       gpio_free(pdata->pin_mosi);
 282 +       gpio_free(pdata->pin_miso);
 283 +       gpio_free(pdata->pin_cs);
 284 +       spi_bitbang_stop(&sp->bitbang);
 285 +       spi_master_put(sp->bitbang.master);
 286 +
 287 +       return 0;
 288 +}
 289 +
 290 +static struct platform_driver spi_gpio_driver = {
 291 +       .driver         = {
 292 +               .name   = SPI_GPIO_PLATDEV_NAME,
 293 +               .owner  = THIS_MODULE,
 294 +       },
 295 +       .probe          = spi_gpio_probe,
 296 +       .remove         = __devexit_p(spi_gpio_remove),
 297 +};
 298 +
 299 +int spi_gpio_next_id(void)
 300 +{
 301 +       static atomic_t counter = ATOMIC_INIT(-1);
 302 +
 303 +       return atomic_inc_return(&counter);
 304 +}
 305 +EXPORT_SYMBOL(spi_gpio_next_id);
 306 +
 307 +static int __init spi_gpio_init(void)
 308 +{
 309 +       int err;
 310 +
 311 +       err = platform_driver_register(&spi_gpio_driver);
 312 +       if (err)
 313 +               printk(KERN_ERR "spi-gpio: register failed: %d\n", err);
 314 +
 315 +       return err;
 316 +}
 317 +module_init(spi_gpio_init);
 318 +
 319 +static void __exit spi_gpio_exit(void)
 320 +{
 321 +       platform_driver_unregister(&spi_gpio_driver);
 322 +}
 323 +module_exit(spi_gpio_exit);
 324 +
 325 +MODULE_AUTHOR("Piot Skamruk <piotr.skamruk at gmail.com>");
 326 +MODULE_DESCRIPTION("Platform independent GPIO bitbanging SPI driver");
 327 +MODULE_LICENSE("GPL v2");
 328 --- a/drivers/spi/Kconfig
 329 +++ b/drivers/spi/Kconfig
 330 @@ -100,6 +100,19 @@ config SPI_BUTTERFLY
 331           inexpensive battery powered microcontroller evaluation board.
 332           This same cable can be used to flash new firmware.
 333
 334 +config SPI_GPIO
 335 +       tristate "GPIO API based bitbanging SPI controller"
 336 +       depends on SPI_MASTER && GENERIC_GPIO
 337 +       select SPI_BITBANG
 338 +       help
 339 +         This is a platform driver that can be used for bitbanging
 340 +         an SPI bus over GPIO pins.
 341 +         Select this if you have any SPI device that is connected via
 342 +         GPIO pins.
 343 +         The module will be called spi_gpio.
 344 +
 345 +         If unsure, say N.
 346 +
 347  config SPI_IMX
 348         tristate "Freescale iMX SPI controller"
 349         depends on SPI_MASTER && ARCH_IMX && EXPERIMENTAL
 350 --- a/drivers/spi/Makefile
 351 +++ b/drivers/spi/Makefile
 352 @@ -16,6 +16,7 @@ obj-$(CONFIG_SPI_BFIN)                        += spi_bfin5xx.
 353  obj-$(CONFIG_SPI_BITBANG)              += spi_bitbang.o
 354  obj-$(CONFIG_SPI_AU1550)               += au1550_spi.o
 355  obj-$(CONFIG_SPI_BUTTERFLY)            += spi_butterfly.o
 356 +obj-$(CONFIG_SPI_GPIO)                 += spi_gpio.o
 357  obj-$(CONFIG_SPI_IMX)                  += spi_imx.o
 358  obj-$(CONFIG_SPI_LM70_LLP)             += spi_lm70llp.o
 359  obj-$(CONFIG_SPI_PXA2XX)               += pxa2xx_spi.o