target/linux/generic-2.6/patches-2.6.28/921-gpio_spi_driver.patch

   1 --- /dev/null
   2 +++ b/include/linux/spi/spi_gpio.h
   3 @@ -0,0 +1,73 @@
   4 +/*
   5 + * spi_gpio interface to platform code
   6 + *
   7 + * Copyright (c) 2008 Piotr Skamruk
   8 + * Copyright (c) 2008 Michael Buesch
   9 + *
  10 + * This program is free software; you can redistribute it and/or modify
  11 + * it under the terms of the GNU General Public License version 2 as
  12 + * published by the Free Software Foundation.
  13 + */
  14 +#ifndef _LINUX_SPI_SPI_GPIO
  15 +#define _LINUX_SPI_SPI_GPIO
  16 +
  17 +#include <linux/types.h>
  18 +#include <linux/spi/spi.h>
  19 +
  20 +
  21 +/**
  22 + * struct spi_gpio_platform_data - Data definitions for a SPI-GPIO device.
  23 + *
  24 + * This structure holds information about a GPIO-based SPI device.
  25 + *
  26 + * @pin_clk: The GPIO pin number of the CLOCK pin.
  27 + *
  28 + * @pin_miso: The GPIO pin number of the MISO pin.
  29 + *
  30 + * @pin_mosi: The GPIO pin number of the MOSI pin.
  31 + *
  32 + * @pin_cs: The GPIO pin number of the CHIPSELECT pin.
  33 + *
  34 + * @cs_activelow: If true, the chip is selected when the CS line is low.
  35 + *
  36 + * @no_spi_delay: If true, no delay is done in the lowlevel bitbanging.
  37 + *                Note that doing no delay is not standards compliant,
  38 + *                but it might be needed to speed up transfers on some
  39 + *                slow embedded machines.
  40 + *
  41 + * @boardinfo_setup: This callback is called after the
  42 + *                   SPI master device was registered, but before the
  43 + *                   device is registered.
  44 + * @boardinfo_setup_data: Data argument passed to boardinfo_setup().
  45 + */
  46 +struct spi_gpio_platform_data {
  47 +       unsigned int pin_clk;
  48 +       unsigned int pin_miso;
  49 +       unsigned int pin_mosi;
  50 +       unsigned int pin_cs;
  51 +       bool cs_activelow;
  52 +       bool no_spi_delay;
  53 +       int (*boardinfo_setup)(struct spi_board_info *bi,
  54 +                              struct spi_master *master,
  55 +                              void *data);
  56 +       void *boardinfo_setup_data;
  57 +};
  58 +
  59 +/**
  60 + * SPI_GPIO_PLATDEV_NAME - The platform device name string.
  61 + *
  62 + * The name string that has to be used for platform_device_alloc
  63 + * when allocating a spi-gpio device.
  64 + */
  65 +#define SPI_GPIO_PLATDEV_NAME  "spi-gpio"
  66 +
  67 +/**
  68 + * spi_gpio_next_id - Get another platform device ID number.
  69 + *
  70 + * This returns the next platform device ID number that has to be used
  71 + * for platform_device_alloc. The ID is opaque and should not be used for
  72 + * anything else.
  73 + */
  74 +int spi_gpio_next_id(void);
  75 +
  76 +#endif /* _LINUX_SPI_SPI_GPIO */
  77 --- /dev/null
  78 +++ b/drivers/spi/spi_gpio.c
  79 @@ -0,0 +1,251 @@
  80 +/*
  81 + * Bitbanging SPI bus driver using GPIO API
  82 + *
  83 + * Copyright (c) 2008 Piotr Skamruk
  84 + * Copyright (c) 2008 Michael Buesch
  85 + *
  86 + * based on spi_s3c2410_gpio.c
  87 + *   Copyright (c) 2006 Ben Dooks
  88 + *   Copyright (c) 2006 Simtec Electronics
  89 + * and on i2c-gpio.c
  90 + *   Copyright (C) 2007 Atmel Corporation
  91 + *
  92 + * This program is free software; you can redistribute it and/or modify
  93 + * it under the terms of the GNU General Public License version 2 as
  94 + * published by the Free Software Foundation.
  95 + */
  96 +
  97 +#include <linux/kernel.h>
  98 +#include <linux/init.h>
  99 +#include <linux/delay.h>
 100 +#include <linux/spinlock.h>
 101 +#include <linux/workqueue.h>
 102 +#include <linux/module.h>
 103 +#include <linux/platform_device.h>
 104 +#include <linux/spi/spi.h>
 105 +#include <linux/spi/spi_bitbang.h>
 106 +#include <linux/spi/spi_gpio.h>
 107 +#include <linux/gpio.h>
 108 +#include <asm/atomic.h>
 109 +
 110 +
 111 +struct spi_gpio {
 112 +       struct spi_bitbang bitbang;
 113 +       struct spi_gpio_platform_data *info;
 114 +       struct platform_device *pdev;
 115 +       struct spi_board_info bi;
 116 +};
 117 +
 118 +
 119 +static inline struct spi_gpio *spidev_to_sg(struct spi_device *dev)
 120 +{
 121 +       return dev->controller_data;
 122 +}
 123 +
 124 +static inline void setsck(struct spi_device *dev, int val)
 125 +{
 126 +       struct spi_gpio *sp = spidev_to_sg(dev);
 127 +       gpio_set_value(sp->info->pin_clk, val ? 1 : 0);
 128 +}
 129 +
 130 +static inline void setmosi(struct spi_device *dev, int val)
 131 +{
 132 +       struct spi_gpio *sp = spidev_to_sg(dev);
 133 +       gpio_set_value(sp->info->pin_mosi, val ? 1 : 0);
 134 +}
 135 +
 136 +static inline u32 getmiso(struct spi_device *dev)
 137 +{
 138 +       struct spi_gpio *sp = spidev_to_sg(dev);
 139 +       return gpio_get_value(sp->info->pin_miso) ? 1 : 0;
 140 +}
 141 +
 142 +static inline void do_spidelay(struct spi_device *dev, unsigned nsecs)
 143 +{
 144 +       struct spi_gpio *sp = spidev_to_sg(dev);
 145 +
 146 +       if (!sp->info->no_spi_delay)
 147 +               ndelay(nsecs);
 148 +}
 149 +
 150 +#define spidelay(nsecs) do {                                   \
 151 +       /* Steal the spi_device pointer from our caller.        \
 152 +        * The bitbang-API should probably get fixed here... */ \
 153 +       do_spidelay(spi, nsecs);                                \
 154 +  } while (0)
 155 +
 156 +#define EXPAND_BITBANG_TXRX
 157 +#include <linux/spi/spi_bitbang.h>
 158 +
 159 +static u32 spi_gpio_txrx_mode0(struct spi_device *spi,
 160 +                              unsigned nsecs, u32 word, u8 bits)
 161 +{
 162 +       return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
 163 +}
 164 +
 165 +static u32 spi_gpio_txrx_mode1(struct spi_device *spi,
 166 +                              unsigned nsecs, u32 word, u8 bits)
 167 +{
 168 +       return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
 169 +}
 170 +
 171 +static u32 spi_gpio_txrx_mode2(struct spi_device *spi,
 172 +                              unsigned nsecs, u32 word, u8 bits)
 173 +{
 174 +       return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
 175 +}
 176 +
 177 +static u32 spi_gpio_txrx_mode3(struct spi_device *spi,
 178 +                              unsigned nsecs, u32 word, u8 bits)
 179 +{
 180 +       return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
 181 +}
 182 +
 183 +static void spi_gpio_chipselect(struct spi_device *dev, int on)
 184 +{
 185 +       struct spi_gpio *sp = spidev_to_sg(dev);
 186 +
 187 +       if (sp->info->cs_activelow)
 188 +               on = !on;
 189 +       gpio_set_value(sp->info->pin_cs, on ? 1 : 0);
 190 +}
 191 +
 192 +static int spi_gpio_probe(struct platform_device *pdev)
 193 +{
 194 +       struct spi_master *master;
 195 +       struct spi_gpio_platform_data *pdata;
 196 +       struct spi_gpio *sp;
 197 +       struct spi_device *spidev;
 198 +       int err;
 199 +
 200 +       pdata = pdev->dev.platform_data;
 201 +       if (!pdata)
 202 +               return -ENXIO;
 203 +
 204 +       err = -ENOMEM;
 205 +       master = spi_alloc_master(&pdev->dev, sizeof(struct spi_gpio));
 206 +       if (!master)
 207 +               goto err_alloc_master;
 208 +
 209 +       sp = spi_master_get_devdata(master);
 210 +       platform_set_drvdata(pdev, sp);
 211 +       sp->info = pdata;
 212 +
 213 +       err = gpio_request(pdata->pin_clk, "spi_clock");
 214 +       if (err)
 215 +               goto err_request_clk;
 216 +       err = gpio_request(pdata->pin_mosi, "spi_mosi");
 217 +       if (err)
 218 +               goto err_request_mosi;
 219 +       err = gpio_request(pdata->pin_miso, "spi_miso");
 220 +       if (err)
 221 +               goto err_request_miso;
 222 +       err = gpio_request(pdata->pin_cs, "spi_cs");
 223 +       if (err)
 224 +               goto err_request_cs;
 225 +
 226 +       sp->bitbang.master = spi_master_get(master);
 227 +       sp->bitbang.master->bus_num = -1;
 228 +       sp->bitbang.master->num_chipselect = 1;
 229 +       sp->bitbang.chipselect = spi_gpio_chipselect;
 230 +       sp->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_mode0;
 231 +       sp->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_mode1;
 232 +       sp->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_mode2;
 233 +       sp->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_mode3;
 234 +
 235 +       gpio_direction_output(pdata->pin_clk, 0);
 236 +       gpio_direction_output(pdata->pin_mosi, 0);
 237 +       gpio_direction_output(pdata->pin_cs,
 238 +                             pdata->cs_activelow ? 1 : 0);
 239 +       gpio_direction_input(pdata->pin_miso);
 240 +
 241 +       err = spi_bitbang_start(&sp->bitbang);
 242 +       if (err)
 243 +               goto err_no_bitbang;
 244 +       err = pdata->boardinfo_setup(&sp->bi, master,
 245 +                                    pdata->boardinfo_setup_data);
 246 +       if (err)
 247 +               goto err_bi_setup;
 248 +       sp->bi.controller_data = sp;
 249 +       spidev = spi_new_device(master, &sp->bi);
 250 +       if (!spidev)
 251 +               goto err_new_dev;
 252 +
 253 +       return 0;
 254 +
 255 +err_new_dev:
 256 +err_bi_setup:
 257 +       spi_bitbang_stop(&sp->bitbang);
 258 +err_no_bitbang:
 259 +       spi_master_put(sp->bitbang.master);
 260 +       gpio_free(pdata->pin_cs);
 261 +err_request_cs:
 262 +       gpio_free(pdata->pin_miso);
 263 +err_request_miso:
 264 +       gpio_free(pdata->pin_mosi);
 265 +err_request_mosi:
 266 +       gpio_free(pdata->pin_clk);
 267 +err_request_clk:
 268 +       kfree(master);
 269 +
 270 +err_alloc_master:
 271 +       return err;
 272 +}
 273 +
 274 +static int __devexit spi_gpio_remove(struct platform_device *pdev)
 275 +{
 276 +       struct spi_gpio *sp;
 277 +       struct spi_gpio_platform_data *pdata;
 278 +
 279 +       pdata = pdev->dev.platform_data;
 280 +       sp = platform_get_drvdata(pdev);
 281 +
 282 +       gpio_free(pdata->pin_clk);
 283 +       gpio_free(pdata->pin_mosi);
 284 +       gpio_free(pdata->pin_miso);
 285 +       gpio_free(pdata->pin_cs);
 286 +       spi_bitbang_stop(&sp->bitbang);
 287 +       spi_master_put(sp->bitbang.master);
 288 +
 289 +       return 0;
 290 +}
 291 +
 292 +static struct platform_driver spi_gpio_driver = {
 293 +       .driver         = {
 294 +               .name   = SPI_GPIO_PLATDEV_NAME,
 295 +               .owner  = THIS_MODULE,
 296 +       },
 297 +       .probe          = spi_gpio_probe,
 298 +       .remove         = __devexit_p(spi_gpio_remove),
 299 +};
 300 +
 301 +int spi_gpio_next_id(void)
 302 +{
 303 +       static atomic_t counter = ATOMIC_INIT(-1);
 304 +
 305 +       return atomic_inc_return(&counter);
 306 +}
 307 +EXPORT_SYMBOL(spi_gpio_next_id);
 308 +
 309 +static int __init spi_gpio_init(void)
 310 +{
 311 +       int err;
 312 +
 313 +       err = platform_driver_register(&spi_gpio_driver);
 314 +       if (err)
 315 +               printk(KERN_ERR "spi-gpio: register failed: %d\n", err);
 316 +
 317 +       return err;
 318 +}
 319 +module_init(spi_gpio_init);
 320 +
 321 +static void __exit spi_gpio_exit(void)
 322 +{
 323 +       platform_driver_unregister(&spi_gpio_driver);
 324 +}
 325 +module_exit(spi_gpio_exit);
 326 +
 327 +MODULE_AUTHOR("Piot Skamruk <piotr.skamruk at gmail.com>");
 328 +MODULE_AUTHOR("Michael Buesch");
 329 +MODULE_DESCRIPTION("Platform independent GPIO bitbanging SPI driver");
 330 +MODULE_LICENSE("GPL v2");
 331 --- a/drivers/spi/Kconfig
 332 +++ b/drivers/spi/Kconfig
 333 @@ -100,6 +100,19 @@ config SPI_BUTTERFLY
 334           inexpensive battery powered microcontroller evaluation board.
 335           This same cable can be used to flash new firmware.
 336
 337 +config SPI_GPIO
 338 +       tristate "GPIO API based bitbanging SPI controller"
 339 +       depends on SPI_MASTER && GENERIC_GPIO
 340 +       select SPI_BITBANG
 341 +       help
 342 +         This is a platform driver that can be used for bitbanging
 343 +         an SPI bus over GPIO pins.
 344 +         Select this if you have any SPI device that is connected via
 345 +         GPIO pins.
 346 +         The module will be called spi_gpio.
 347 +
 348 +         If unsure, say N.
 349 +
 350  config SPI_IMX
 351         tristate "Freescale iMX SPI controller"
 352         depends on ARCH_IMX && EXPERIMENTAL
 353 --- a/drivers/spi/Makefile
 354 +++ b/drivers/spi/Makefile
 355 @@ -16,6 +16,7 @@ obj-$(CONFIG_SPI_BFIN)                        += spi_bfin5xx.
 356  obj-$(CONFIG_SPI_BITBANG)              += spi_bitbang.o
 357  obj-$(CONFIG_SPI_AU1550)               += au1550_spi.o
 358  obj-$(CONFIG_SPI_BUTTERFLY)            += spi_butterfly.o
 359 +obj-$(CONFIG_SPI_GPIO)                 += spi_gpio.o
 360  obj-$(CONFIG_SPI_IMX)                  += spi_imx.o
 361  obj-$(CONFIG_SPI_LM70_LLP)             += spi_lm70llp.o
 362  obj-$(CONFIG_SPI_PXA2XX)               += pxa2xx_spi.o
 363 --- a/MAINTAINERS
 364 +++ b/MAINTAINERS
 365 @@ -4027,6 +4027,11 @@ M:       jbglaw@lug-owl.de
 366  L:     linux-kernel@vger.kernel.org
 367  S:     Maintained
 368
 369 +SPI GPIO MASTER DRIVER
 370 +P:     Michael Buesch
 371 +M:     mb@bu3sch.de
 372 +S:     Maintained
 373 +
 374  STABLE BRANCH
 375  P:     Greg Kroah-Hartman
 376  M:     greg@kroah.com