target/linux/generic-2.6/patches-2.6.25/922-gpiommc.patch

   1 Index: linux-2.6.25.17/drivers/mmc/host/gpiommc.c
   2 ===================================================================
   3 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
   4 +++ linux-2.6.25.17/drivers/mmc/host/gpiommc.c  2008-10-18 23:33:54.000000000 +0200
   5 @@ -0,0 +1,605 @@
   6 +/*
   7 + * Driver an MMC/SD card on a bitbanging GPIO SPI bus.
   8 + * This module hooks up the mmc_spi and spi_gpio modules and also
   9 + * provides a configfs interface.
  10 + *
  11 + * Licensed under the GNU/GPL. See COPYING for details.
  12 + */
  13 +
  14 +#include <linux/mmc/gpiommc.h>
  15 +#include <linux/platform_device.h>
  16 +#include <linux/list.h>
  17 +#include <linux/mutex.h>
  18 +#include <linux/spi/spi_gpio.h>
  19 +#include <linux/configfs.h>
  20 +#include <linux/gpio.h>
  21 +#include <asm/atomic.h>
  22 +
  23 +
  24 +#define PFX                            "gpio-mmc: "
  25 +
  26 +
  27 +struct gpiommc_device {
  28 +       struct platform_device *pdev;
  29 +       struct platform_device *spi_pdev;
  30 +       struct spi_board_info boardinfo;
  31 +};
  32 +
  33 +
  34 +MODULE_DESCRIPTION("GPIO based MMC driver");
  35 +MODULE_LICENSE("GPL");
  36 +
  37 +
  38 +static int gpiommc_boardinfo_setup(struct spi_board_info *bi,
  39 +                                  struct spi_master *master,
  40 +                                  void *data)
  41 +{
  42 +       struct gpiommc_device *d = data;
  43 +       struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
  44 +
  45 +       /* Bind the SPI master to the MMC-SPI host driver. */
  46 +       strlcpy(bi->modalias, "mmc_spi", sizeof(bi->modalias));
  47 +
  48 +       bi->max_speed_hz = pdata->max_bus_speed;
  49 +       bi->bus_num = master->bus_num;
  50 +       bi->mode = pdata->mode;
  51 +
  52 +       return 0;
  53 +}
  54 +
  55 +static int gpiommc_probe(struct platform_device *pdev)
  56 +{
  57 +       struct gpiommc_platform_data *mmc_pdata = pdev->dev.platform_data;
  58 +       struct spi_gpio_platform_data spi_pdata;
  59 +       struct gpiommc_device *d;
  60 +       int err;
  61 +
  62 +       err = -ENXIO;
  63 +       if (!mmc_pdata)
  64 +               goto error;
  65 +
  66 +#ifdef CONFIG_MMC_SPI_MODULE
  67 +       err = request_module("mmc_spi");
  68 +       if (err) {
  69 +               printk(KERN_WARNING PFX
  70 +                      "Failed to request mmc_spi module.\n");
  71 +       }
  72 +#endif /* CONFIG_MMC_SPI_MODULE */
  73 +
  74 +       /* Allocate the GPIO-MMC device */
  75 +       err = -ENOMEM;
  76 +       d = kzalloc(sizeof(*d), GFP_KERNEL);
  77 +       if (!d)
  78 +               goto error;
  79 +       d->pdev = pdev;
  80 +
  81 +       /* Create the SPI-GPIO device */
  82 +       d->spi_pdev = platform_device_alloc(SPI_GPIO_PLATDEV_NAME,
  83 +                                           spi_gpio_next_id());
  84 +       if (!d->spi_pdev)
  85 +               goto err_free_d;
  86 +
  87 +       memset(&spi_pdata, 0, sizeof(spi_pdata));
  88 +       spi_pdata.pin_clk = mmc_pdata->pins.gpio_clk;
  89 +       spi_pdata.pin_miso = mmc_pdata->pins.gpio_do;
  90 +       spi_pdata.pin_mosi = mmc_pdata->pins.gpio_di;
  91 +       spi_pdata.pin_cs = mmc_pdata->pins.gpio_cs;
  92 +       spi_pdata.cs_activelow = mmc_pdata->pins.cs_activelow;
  93 +       spi_pdata.no_spi_delay = mmc_pdata->no_spi_delay;
  94 +       spi_pdata.boardinfo_setup = gpiommc_boardinfo_setup;
  95 +       spi_pdata.boardinfo_setup_data = d;
  96 +
  97 +       err = platform_device_add_data(d->spi_pdev, &spi_pdata,
  98 +                                      sizeof(spi_pdata));
  99 +       if (err)
 100 +               goto err_free_pdev;
 101 +       err = platform_device_add(d->spi_pdev);
 102 +       if (err)
 103 +               goto err_free_pdata;
 104 +       platform_set_drvdata(pdev, d);
 105 +
 106 +       printk(KERN_INFO PFX "MMC-Card \"%s\" "
 107 +              "attached to GPIO pins di=%u, do=%u, clk=%u, cs=%u\n",
 108 +              mmc_pdata->name, mmc_pdata->pins.gpio_di,
 109 +              mmc_pdata->pins.gpio_do,
 110 +              mmc_pdata->pins.gpio_clk,
 111 +              mmc_pdata->pins.gpio_cs);
 112 +
 113 +       return 0;
 114 +
 115 +err_free_pdata:
 116 +       kfree(d->spi_pdev->dev.platform_data);
 117 +       d->spi_pdev->dev.platform_data = NULL;
 118 +err_free_pdev:
 119 +       platform_device_put(d->spi_pdev);
 120 +err_free_d:
 121 +       kfree(d);
 122 +error:
 123 +       return err;
 124 +}
 125 +
 126 +static int gpiommc_remove(struct platform_device *pdev)
 127 +{
 128 +       struct gpiommc_device *d = platform_get_drvdata(pdev);
 129 +       struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
 130 +
 131 +       platform_device_unregister(d->spi_pdev);
 132 +       printk(KERN_INFO PFX "GPIO based MMC-Card \"%s\" removed\n",
 133 +              pdata->name);
 134 +       platform_device_put(d->spi_pdev);
 135 +
 136 +       return 0;
 137 +}
 138 +
 139 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 140 +
 141 +/* A device that was created through configfs */
 142 +struct gpiommc_configfs_device {
 143 +       struct config_item item;
 144 +       /* The platform device, after registration. */
 145 +       struct platform_device *pdev;
 146 +       /* The configuration */
 147 +       struct gpiommc_platform_data pdata;
 148 +};
 149 +
 150 +#define GPIO_INVALID   -1
 151 +
 152 +static inline bool gpiommc_is_registered(struct gpiommc_configfs_device *dev)
 153 +{
 154 +       return (dev->pdev != NULL);
 155 +}
 156 +
 157 +static inline struct gpiommc_configfs_device *ci_to_gpiommc(struct config_item *item)
 158 +{
 159 +       return item ? container_of(item, struct gpiommc_configfs_device, item) : NULL;
 160 +}
 161 +
 162 +static struct configfs_attribute gpiommc_attr_DI = {
 163 +       .ca_owner = THIS_MODULE,
 164 +       .ca_name = "gpio_data_in",
 165 +       .ca_mode = S_IRUGO | S_IWUSR,
 166 +};
 167 +
 168 +static struct configfs_attribute gpiommc_attr_DO = {
 169 +       .ca_owner = THIS_MODULE,
 170 +       .ca_name = "gpio_data_out",
 171 +       .ca_mode = S_IRUGO | S_IWUSR,
 172 +};
 173 +
 174 +static struct configfs_attribute gpiommc_attr_CLK = {
 175 +       .ca_owner = THIS_MODULE,
 176 +       .ca_name = "gpio_clock",
 177 +       .ca_mode = S_IRUGO | S_IWUSR,
 178 +};
 179 +
 180 +static struct configfs_attribute gpiommc_attr_CS = {
 181 +       .ca_owner = THIS_MODULE,
 182 +       .ca_name = "gpio_chipselect",
 183 +       .ca_mode = S_IRUGO | S_IWUSR,
 184 +};
 185 +
 186 +static struct configfs_attribute gpiommc_attr_CS_activelow = {
 187 +       .ca_owner = THIS_MODULE,
 188 +       .ca_name = "gpio_chipselect_activelow",
 189 +       .ca_mode = S_IRUGO | S_IWUSR,
 190 +};
 191 +
 192 +static struct configfs_attribute gpiommc_attr_spimode = {
 193 +       .ca_owner = THIS_MODULE,
 194 +       .ca_name = "spi_mode",
 195 +       .ca_mode = S_IRUGO | S_IWUSR,
 196 +};
 197 +
 198 +static struct configfs_attribute gpiommc_attr_spidelay = {
 199 +       .ca_owner = THIS_MODULE,
 200 +       .ca_name = "spi_delay",
 201 +       .ca_mode = S_IRUGO | S_IWUSR,
 202 +};
 203 +
 204 +static struct configfs_attribute gpiommc_attr_max_bus_speed = {
 205 +       .ca_owner = THIS_MODULE,
 206 +       .ca_name = "max_bus_speed",
 207 +       .ca_mode = S_IRUGO | S_IWUSR,
 208 +};
 209 +
 210 +static struct configfs_attribute gpiommc_attr_register = {
 211 +       .ca_owner = THIS_MODULE,
 212 +       .ca_name = "register",
 213 +       .ca_mode = S_IRUGO | S_IWUSR,
 214 +};
 215 +
 216 +static struct configfs_attribute *gpiommc_config_attrs[] = {
 217 +       &gpiommc_attr_DI,
 218 +       &gpiommc_attr_DO,
 219 +       &gpiommc_attr_CLK,
 220 +       &gpiommc_attr_CS,
 221 +       &gpiommc_attr_CS_activelow,
 222 +       &gpiommc_attr_spimode,
 223 +       &gpiommc_attr_spidelay,
 224 +       &gpiommc_attr_max_bus_speed,
 225 +       &gpiommc_attr_register,
 226 +       NULL,
 227 +};
 228 +
 229 +static ssize_t gpiommc_config_attr_show(struct config_item *item,
 230 +                                       struct configfs_attribute *attr,
 231 +                                       char *page)
 232 +{
 233 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 234 +       ssize_t count = 0;
 235 +       unsigned int gpio;
 236 +       int err = 0;
 237 +
 238 +       if (attr == &gpiommc_attr_DI) {
 239 +               gpio = dev->pdata.pins.gpio_di;
 240 +               if (gpio == GPIO_INVALID)
 241 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 242 +               else
 243 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 244 +               goto out;
 245 +       }
 246 +       if (attr == &gpiommc_attr_DO) {
 247 +               gpio = dev->pdata.pins.gpio_do;
 248 +               if (gpio == GPIO_INVALID)
 249 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 250 +               else
 251 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 252 +               goto out;
 253 +       }
 254 +       if (attr == &gpiommc_attr_CLK) {
 255 +               gpio = dev->pdata.pins.gpio_clk;
 256 +               if (gpio == GPIO_INVALID)
 257 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 258 +               else
 259 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 260 +               goto out;
 261 +       }
 262 +       if (attr == &gpiommc_attr_CS) {
 263 +               gpio = dev->pdata.pins.gpio_cs;
 264 +               if (gpio == GPIO_INVALID)
 265 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 266 +               else
 267 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 268 +               goto out;
 269 +       }
 270 +       if (attr == &gpiommc_attr_CS_activelow) {
 271 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 272 +                                dev->pdata.pins.cs_activelow);
 273 +               goto out;
 274 +       }
 275 +       if (attr == &gpiommc_attr_spimode) {
 276 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 277 +                                dev->pdata.mode);
 278 +               goto out;
 279 +       }
 280 +       if (attr == &gpiommc_attr_spidelay) {
 281 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 282 +                                !dev->pdata.no_spi_delay);
 283 +               goto out;
 284 +       }
 285 +       if (attr == &gpiommc_attr_max_bus_speed) {
 286 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 287 +                                dev->pdata.max_bus_speed);
 288 +               goto out;
 289 +       }
 290 +       if (attr == &gpiommc_attr_register) {
 291 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 292 +                                gpiommc_is_registered(dev));
 293 +               goto out;
 294 +       }
 295 +       WARN_ON(1);
 296 +       err = -ENOSYS;
 297 +out:
 298 +       return err ? err : count;
 299 +}
 300 +
 301 +static int gpiommc_do_register(struct gpiommc_configfs_device *dev,
 302 +                              const char *name)
 303 +{
 304 +       int err;
 305 +
 306 +       if (gpiommc_is_registered(dev))
 307 +               return 0;
 308 +
 309 +       if (!gpio_is_valid(dev->pdata.pins.gpio_di) ||
 310 +           !gpio_is_valid(dev->pdata.pins.gpio_do) ||
 311 +           !gpio_is_valid(dev->pdata.pins.gpio_clk) ||
 312 +           !gpio_is_valid(dev->pdata.pins.gpio_cs)) {
 313 +               printk(KERN_ERR PFX
 314 +                      "configfs: Invalid GPIO pin number(s)\n");
 315 +               return -EINVAL;
 316 +       }
 317 +
 318 +       strlcpy(dev->pdata.name, name,
 319 +               sizeof(dev->pdata.name));
 320 +
 321 +       dev->pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME,
 322 +                                         gpiommc_next_id());
 323 +       if (!dev->pdev)
 324 +               return -ENOMEM;
 325 +       err = platform_device_add_data(dev->pdev, &dev->pdata,
 326 +                                      sizeof(dev->pdata));
 327 +       if (err) {
 328 +               platform_device_put(dev->pdev);
 329 +               return err;
 330 +       }
 331 +       err = platform_device_add(dev->pdev);
 332 +       if (err) {
 333 +               platform_device_put(dev->pdev);
 334 +               return err;
 335 +       }
 336 +
 337 +       return 0;
 338 +}
 339 +
 340 +static void gpiommc_do_unregister(struct gpiommc_configfs_device *dev)
 341 +{
 342 +       if (!gpiommc_is_registered(dev))
 343 +               return;
 344 +
 345 +       platform_device_unregister(dev->pdev);
 346 +       dev->pdev = NULL;
 347 +}
 348 +
 349 +static ssize_t gpiommc_config_attr_store(struct config_item *item,
 350 +                                        struct configfs_attribute *attr,
 351 +                                        const char *page, size_t count)
 352 +{
 353 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 354 +       int err = -EINVAL;
 355 +       unsigned long data;
 356 +
 357 +       if (attr == &gpiommc_attr_register) {
 358 +               err = strict_strtoul(page, 10, &data);
 359 +               if (err)
 360 +                       goto out;
 361 +               err = -EINVAL;
 362 +               if (data == 1)
 363 +                       err = gpiommc_do_register(dev, item->ci_name);
 364 +               if (data == 0) {
 365 +                       gpiommc_do_unregister(dev);
 366 +                       err = 0;
 367 +               }
 368 +               goto out;
 369 +       }
 370 +
 371 +       if (gpiommc_is_registered(dev)) {
 372 +               /* The rest of the config parameters can only be set
 373 +                * as long as the device is not registered, yet. */
 374 +               err = -EBUSY;
 375 +               goto out;
 376 +       }
 377 +
 378 +       if (attr == &gpiommc_attr_DI) {
 379 +               err = strict_strtoul(page, 10, &data);
 380 +               if (err)
 381 +                       goto out;
 382 +               err = -EINVAL;
 383 +               if (!gpio_is_valid(data))
 384 +                       goto out;
 385 +               dev->pdata.pins.gpio_di = data;
 386 +               err = 0;
 387 +               goto out;
 388 +       }
 389 +       if (attr == &gpiommc_attr_DO) {
 390 +               err = strict_strtoul(page, 10, &data);
 391 +               if (err)
 392 +                       goto out;
 393 +               err = -EINVAL;
 394 +               if (!gpio_is_valid(data))
 395 +                       goto out;
 396 +               dev->pdata.pins.gpio_do = data;
 397 +               err = 0;
 398 +               goto out;
 399 +       }
 400 +       if (attr == &gpiommc_attr_CLK) {
 401 +               err = strict_strtoul(page, 10, &data);
 402 +               if (err)
 403 +                       goto out;
 404 +               err = -EINVAL;
 405 +               if (!gpio_is_valid(data))
 406 +                       goto out;
 407 +               dev->pdata.pins.gpio_clk = data;
 408 +               err = 0;
 409 +               goto out;
 410 +       }
 411 +       if (attr == &gpiommc_attr_CS) {
 412 +               err = strict_strtoul(page, 10, &data);
 413 +               if (err)
 414 +                       goto out;
 415 +               err = -EINVAL;
 416 +               if (!gpio_is_valid(data))
 417 +                       goto out;
 418 +               dev->pdata.pins.gpio_cs = data;
 419 +               err = 0;
 420 +               goto out;
 421 +       }
 422 +       if (attr == &gpiommc_attr_CS_activelow) {
 423 +               err = strict_strtoul(page, 10, &data);
 424 +               if (err)
 425 +                       goto out;
 426 +               err = -EINVAL;
 427 +               if (data != 0 && data != 1)
 428 +                       goto out;
 429 +               dev->pdata.pins.cs_activelow = data;
 430 +               err = 0;
 431 +               goto out;
 432 +       }
 433 +       if (attr == &gpiommc_attr_spimode) {
 434 +               err = strict_strtoul(page, 10, &data);
 435 +               if (err)
 436 +                       goto out;
 437 +               err = -EINVAL;
 438 +               switch (data) {
 439 +               case 0:
 440 +                       dev->pdata.mode = SPI_MODE_0;
 441 +                       break;
 442 +               case 1:
 443 +                       dev->pdata.mode = SPI_MODE_1;
 444 +                       break;
 445 +               case 2:
 446 +                       dev->pdata.mode = SPI_MODE_2;
 447 +                       break;
 448 +               case 3:
 449 +                       dev->pdata.mode = SPI_MODE_3;
 450 +                       break;
 451 +               default:
 452 +                       goto out;
 453 +               }
 454 +               err = 0;
 455 +               goto out;
 456 +       }
 457 +       if (attr == &gpiommc_attr_spidelay) {
 458 +               err = strict_strtoul(page, 10, &data);
 459 +               if (err)
 460 +                       goto out;
 461 +               err = -EINVAL;
 462 +               if (data != 0 && data != 1)
 463 +                       goto out;
 464 +               dev->pdata.no_spi_delay = !data;
 465 +               err = 0;
 466 +               goto out;
 467 +       }
 468 +       if (attr == &gpiommc_attr_max_bus_speed) {
 469 +               err = strict_strtoul(page, 10, &data);
 470 +               if (err)
 471 +                       goto out;
 472 +               err = -EINVAL;
 473 +               if (data > UINT_MAX)
 474 +                       goto out;
 475 +               dev->pdata.max_bus_speed = data;
 476 +               err = 0;
 477 +               goto out;
 478 +       }
 479 +       WARN_ON(1);
 480 +       err = -ENOSYS;
 481 +out:
 482 +       return err ? err : count;
 483 +}
 484 +
 485 +static void gpiommc_config_item_release(struct config_item *item)
 486 +{
 487 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 488 +
 489 +       kfree(dev);
 490 +}
 491 +
 492 +static struct configfs_item_operations gpiommc_config_item_ops = {
 493 +       .release                = gpiommc_config_item_release,
 494 +       .show_attribute         = gpiommc_config_attr_show,
 495 +       .store_attribute        = gpiommc_config_attr_store,
 496 +};
 497 +
 498 +static struct config_item_type gpiommc_dev_ci_type = {
 499 +       .ct_item_ops    = &gpiommc_config_item_ops,
 500 +       .ct_attrs       = gpiommc_config_attrs,
 501 +       .ct_owner       = THIS_MODULE,
 502 +};
 503 +
 504 +static struct config_item *gpiommc_make_item(struct config_group *group,
 505 +                                            const char *name)
 506 +{
 507 +       struct gpiommc_configfs_device *dev;
 508 +
 509 +       if (strlen(name) > GPIOMMC_MAX_NAMELEN) {
 510 +               printk(KERN_ERR PFX "configfs: device name too long\n");
 511 +               return NULL;
 512 +       }
 513 +
 514 +       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 515 +       if (!dev)
 516 +               return NULL;
 517 +
 518 +       config_item_init_type_name(&dev->item, name,
 519 +                                  &gpiommc_dev_ci_type);
 520 +
 521 +       /* Assign default configuration */
 522 +       dev->pdata.pins.gpio_di = GPIO_INVALID;
 523 +       dev->pdata.pins.gpio_do = GPIO_INVALID;
 524 +       dev->pdata.pins.gpio_clk = GPIO_INVALID;
 525 +       dev->pdata.pins.gpio_cs = GPIO_INVALID;
 526 +       dev->pdata.pins.cs_activelow = 1;
 527 +       dev->pdata.mode = SPI_MODE_0;
 528 +       dev->pdata.no_spi_delay = 0;
 529 +       dev->pdata.max_bus_speed = 5000000; /* 5 MHz */
 530 +
 531 +       return &(dev->item);
 532 +}
 533 +
 534 +static void gpiommc_drop_item(struct config_group *group,
 535 +                             struct config_item *item)
 536 +{
 537 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 538 +
 539 +       gpiommc_do_unregister(dev);
 540 +       kfree(dev);
 541 +}
 542 +
 543 +static struct configfs_group_operations gpiommc_ct_group_ops = {
 544 +       .make_item      = gpiommc_make_item,
 545 +       .drop_item      = gpiommc_drop_item,
 546 +};
 547 +
 548 +static struct config_item_type gpiommc_ci_type = {
 549 +       .ct_group_ops   = &gpiommc_ct_group_ops,
 550 +       .ct_owner       = THIS_MODULE,
 551 +};
 552 +
 553 +static struct configfs_subsystem gpiommc_subsys = {
 554 +       .su_group = {
 555 +               .cg_item = {
 556 +                       .ci_namebuf = GPIOMMC_PLATDEV_NAME,
 557 +                       .ci_type = &gpiommc_ci_type,
 558 +               },
 559 +       },
 560 +       .su_mutex = __MUTEX_INITIALIZER(gpiommc_subsys.su_mutex),
 561 +};
 562 +
 563 +#endif /* CONFIG_GPIOMMC_CONFIGFS */
 564 +
 565 +static struct platform_driver gpiommc_plat_driver = {
 566 +       .probe  = gpiommc_probe,
 567 +       .remove = gpiommc_remove,
 568 +       .driver = {
 569 +               .name   = GPIOMMC_PLATDEV_NAME,
 570 +               .owner  = THIS_MODULE,
 571 +       },
 572 +};
 573 +
 574 +int gpiommc_next_id(void)
 575 +{
 576 +       static atomic_t counter = ATOMIC_INIT(-1);
 577 +
 578 +       return atomic_inc_return(&counter);
 579 +}
 580 +EXPORT_SYMBOL(gpiommc_next_id);
 581 +
 582 +static int __init gpiommc_modinit(void)
 583 +{
 584 +       int err;
 585 +
 586 +       err = platform_driver_register(&gpiommc_plat_driver);
 587 +       if (err)
 588 +               return err;
 589 +
 590 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 591 +       config_group_init(&gpiommc_subsys.su_group);
 592 +       err = configfs_register_subsystem(&gpiommc_subsys);
 593 +       if (err) {
 594 +               platform_driver_unregister(&gpiommc_plat_driver);
 595 +               return err;
 596 +       }
 597 +#endif /* CONFIG_GPIOMMC_CONFIGFS */
 598 +
 599 +       return 0;
 600 +}
 601 +module_init(gpiommc_modinit);
 602 +
 603 +static void __exit gpiommc_modexit(void)
 604 +{
 605 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 606 +       configfs_unregister_subsystem(&gpiommc_subsys);
 607 +#endif
 608 +       platform_driver_unregister(&gpiommc_plat_driver);
 609 +}
 610 +module_exit(gpiommc_modexit);
 611 Index: linux-2.6.25.17/drivers/mmc/host/Kconfig
 612 ===================================================================
 613 --- linux-2.6.25.17.orig/drivers/mmc/host/Kconfig       2008-10-18 23:30:41.000000000 +0200
 614 +++ linux-2.6.25.17/drivers/mmc/host/Kconfig    2008-10-18 23:32:54.000000000 +0200
 615 @@ -130,3 +130,27 @@ config MMC_SPI
 616
 617           If unsure, or if your system has no SPI master driver, say N.
 618
 619 +config GPIOMMC
 620 +       tristate "MMC/SD over GPIO-based SPI"
 621 +       depends on MMC && MMC_SPI && SPI_GPIO
 622 +       help
 623 +         This driver hooks up the mmc_spi and spi_gpio modules so that
 624 +         MMC/SD cards can be used on a GPIO based bus by bitbanging
 625 +         the SPI protocol in software.
 626 +
 627 +         This driver provides a configfs interface to dynamically create
 628 +         and destroy GPIO-based MMC/SD card devices. It also provides
 629 +         a platform device interface API.
 630 +         See Documentation/gpiommc.txt for details.
 631 +
 632 +         The module will be called gpiommc.
 633 +
 634 +         If unsure, say N.
 635 +
 636 +config GPIOMMC_CONFIGFS
 637 +       bool
 638 +       depends on GPIOMMC && CONFIGFS_FS
 639 +       default y
 640 +       help
 641 +         This option automatically enables configfs support for gpiommc
 642 +         if configfs is available.
 643 Index: linux-2.6.25.17/drivers/mmc/host/Makefile
 644 ===================================================================
 645 --- linux-2.6.25.17.orig/drivers/mmc/host/Makefile      2008-10-18 23:30:41.000000000 +0200
 646 +++ linux-2.6.25.17/drivers/mmc/host/Makefile   2008-10-18 23:32:54.000000000 +0200
 647 @@ -17,4 +17,4 @@ obj-$(CONFIG_MMC_OMAP)                += omap.o
 648  obj-$(CONFIG_MMC_AT91)         += at91_mci.o
 649  obj-$(CONFIG_MMC_TIFM_SD)      += tifm_sd.o
 650  obj-$(CONFIG_MMC_SPI)          += mmc_spi.o
 651 -
 652 +obj-$(CONFIG_GPIOMMC)          += gpiommc.o
 653 Index: linux-2.6.25.17/include/linux/mmc/gpiommc.h
 654 ===================================================================
 655 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
 656 +++ linux-2.6.25.17/include/linux/mmc/gpiommc.h 2008-10-18 23:34:21.000000000 +0200
 657 @@ -0,0 +1,69 @@
 658 +/*
 659 + * Device driver for MMC/SD cards driven over a GPIO bus.
 660 + *
 661 + * Licensed under the GNU/GPL version 2.
 662 + */
 663 +#ifndef LINUX_GPIOMMC_H_
 664 +#define LINUX_GPIOMMC_H_
 665 +
 666 +#include <linux/types.h>
 667 +
 668 +
 669 +#define GPIOMMC_MAX_NAMELEN            15
 670 +#define GPIOMMC_MAX_NAMELEN_STR                __stringify(GPIOMMC_MAX_NAMELEN)
 671 +
 672 +/**
 673 + * struct gpiommc_pins - Hardware pin assignments
 674 + *
 675 + * @gpio_di: The GPIO number of the DATA IN pin
 676 + * @gpio_do: The GPIO number of the DATA OUT pin
 677 + * @gpio_clk: The GPIO number of the CLOCK pin
 678 + * @gpio_cs: The GPIO number of the CHIPSELECT pin
 679 + * @cs_activelow: If true, the chip is considered selected if @gpio_cs is low.
 680 + */
 681 +struct gpiommc_pins {
 682 +       unsigned int gpio_di;
 683 +       unsigned int gpio_do;
 684 +       unsigned int gpio_clk;
 685 +       unsigned int gpio_cs;
 686 +       bool cs_activelow;
 687 +};
 688 +
 689 +/**
 690 + * struct gpiommc_platform_data - Platform data for a MMC-over-SPI-GPIO device.
 691 + *
 692 + * @name: The unique name string of the device.
 693 + * @pins: The hardware pin assignments.
 694 + * @mode: The hardware mode. This is either SPI_MODE_0,
 695 + *        SPI_MODE_1, SPI_MODE_2 or SPI_MODE_3. See the SPI documentation.
 696 + * @no_spi_delay: Do not use delays in the lowlevel SPI bitbanging code.
 697 + *                This is not standards compliant, but may be required for some
 698 + *                embedded machines to gain reasonable speed.
 699 + * @max_bus_speed: The maximum speed of the SPI bus, in Hertz.
 700 + */
 701 +struct gpiommc_platform_data {
 702 +       char name[GPIOMMC_MAX_NAMELEN + 1];
 703 +       struct gpiommc_pins pins;
 704 +       u8 mode;
 705 +       bool no_spi_delay;
 706 +       unsigned int max_bus_speed;
 707 +};
 708 +
 709 +/**
 710 + * GPIOMMC_PLATDEV_NAME - The platform device name string.
 711 + *
 712 + * The name string that has to be used for platform_device_alloc
 713 + * when allocating a gpiommc device.
 714 + */
 715 +#define GPIOMMC_PLATDEV_NAME   "gpiommc"
 716 +
 717 +/**
 718 + * gpiommc_next_id - Get another platform device ID number.
 719 + *
 720 + * This returns the next platform device ID number that has to be used
 721 + * for platform_device_alloc. The ID is opaque and should not be used for
 722 + * anything else.
 723 + */
 724 +int gpiommc_next_id(void);
 725 +
 726 +#endif /* LINUX_GPIOMMC_H_ */
 727 Index: linux-2.6.25.17/Documentation/gpiommc.txt
 728 ===================================================================
 729 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
 730 +++ linux-2.6.25.17/Documentation/gpiommc.txt   2008-10-18 23:32:54.000000000 +0200
 731 @@ -0,0 +1,97 @@
 732 +GPIOMMC - Driver for an MMC/SD card on a bitbanging GPIO SPI bus
 733 +================================================================
 734 +
 735 +The gpiommc module hooks up the mmc_spi and spi_gpio modules for running an
 736 +MMC or SD card on GPIO pins.
 737 +
 738 +Two interfaces for registering a new MMC/SD card device are provided:
 739 +A static platform-device based mechanism and a dynamic configfs based interface.
 740 +
 741 +
 742 +Registering devices via platform-device
 743 +=======================================
 744 +
 745 +The platform-device interface is used for registering MMC/SD devices that are
 746 +part of the hardware platform. This is most useful only for embedded machines
 747 +with MMC/SD devices statically connected to the platform GPIO bus.
 748 +
 749 +The data structures are declared in <linux/mmc/gpiommc.h>.
 750 +
 751 +To register a new device, define an instance of struct gpiommc_platform_data.
 752 +This structure holds any information about how the device is hooked up to the
 753 +GPIO pins and what hardware modes the device supports. See the docbook-style
 754 +documentation in the header file for more information on the struct fields.
 755 +
 756 +Then allocate a new instance of a platform device by doing:
 757 +
 758 +       pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME, gpiommc_next_id());
 759 +
 760 +This will allocate the platform device data structures and hook it up to the
 761 +gpiommc driver.
 762 +Then add the gpiommc_platform_data to the platform device.
 763 +
 764 +       err = platform_device_add_data(pdev, pdata, sizeof(struct gpiommc_platform_data));
 765 +
 766 +You may free the local instance of struct gpiommc_platform_data now. (So the
 767 +struct may be allocated on the stack, too).
 768 +Now simply register the platform device.
 769 +
 770 +       err = platform_device_add(pdev);
 771 +
 772 +Done. The gpiommc probe routine will be invoked now and you should see a kernel
 773 +log message for the added device.
 774 +
 775 +
 776 +Registering devices via configfs
 777 +================================
 778 +
 779 +MMC/SD cards connected via GPIO often are a pretty dynamic thing, as for example
 780 +selfmade hacks for soldering an MMC/SD card to standard GPIO pins on embedded
 781 +hardware are a common situation.
 782 +So we provide a dynamic interface to conveniently handle adding and removing
 783 +devices from userspace, without the need to recompile the kernel.
 784 +
 785 +The "gpiommc" subdirectory at the configfs mountpoint is used for handling
 786 +the dynamic configuration.
 787 +
 788 +To create a new device, it must first be allocated with mkdir.
 789 +The following command will allocate a device named "my_mmc":
 790 +       mkdir /config/gpiommc/my_mmc
 791 +
 792 +There are several configuration files available in the new
 793 +/config/gpiommc/my_mmc/ directory:
 794 +
 795 +gpio_data_in                   = The SPI data-IN GPIO pin number.
 796 +gpio_data_out                  = The SPI data-OUT GPIO pin number.
 797 +gpio_clock                     = The SPI Clock GPIO pin number.
 798 +gpio_chipselect                        = The SPI Chipselect GPIO pin number.
 799 +gpio_chipselect_activelow      = Boolean. If 0, Chipselect is active-HIGH.
 800 +                                 If 1, Chipselect is active-LOW.
 801 +spi_mode                       = The SPI data mode. Can be 0-3.
 802 +spi_delay                      = Enable all delays in the lowlevel bitbanging.
 803 +max_bus_speed                  = The maximum SPI bus speed. In Hertz.
 804 +
 805 +register                       = Not a configuration parameter.
 806 +                                 Used to register the configured card
 807 +                                 with the kernel.
 808 +
 809 +The device must first get configured and then registered by writing "1" to
 810 +the "register" file.
 811 +The configuration parameters "gpio_data_in", "gpio_data_out", "gpio_clock"
 812 +and "gpio_chipselect" are essential and _must_ be configured before writing
 813 +"1" to the "register" file. The registration will fail, otherwise.
 814 +
 815 +The default values for the other parameters are:
 816 +gpio_chipselect_activelow      = 1             (CS active-LOW)
 817 +spi_mode                       = 0             (SPI_MODE_0)
 818 +spi_delay                      = 1             (enabled)
 819 +max_bus_speed                  = 5000000       (5 Mhz)
 820 +
 821 +Configuration values can not be changed after registration. To unregister
 822 +the device, write a "0" to the "register" file. The configuration can be
 823 +changed again after unregistering.
 824 +
 825 +To completely remove the device, simply rmdir the directory
 826 +(/config/gpiommc/my_mmc in this example).
 827 +There's no need to first unregister the device before removing it. That will
 828 +be done automatically.