target/linux/generic-2.6/patches-2.6.28/922-gpiommc.patch

   1 Index: linux-2.6.28.2/drivers/mmc/host/gpiommc.c
   2 ===================================================================
   3 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
   4 +++ linux-2.6.28.2/drivers/mmc/host/gpiommc.c   2009-02-10 17:16:16.000000000 +0100
   5 @@ -0,0 +1,608 @@
   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 + * Copyright 2008 Michael Buesch <mb@bu3sch.de>
  12 + *
  13 + * Licensed under the GNU/GPL. See COPYING for details.
  14 + */
  15 +
  16 +#include <linux/mmc/gpiommc.h>
  17 +#include <linux/platform_device.h>
  18 +#include <linux/list.h>
  19 +#include <linux/mutex.h>
  20 +#include <linux/spi/spi_gpio_old.h>
  21 +#include <linux/configfs.h>
  22 +#include <linux/gpio.h>
  23 +#include <asm/atomic.h>
  24 +
  25 +
  26 +#define PFX                            "gpio-mmc: "
  27 +
  28 +
  29 +struct gpiommc_device {
  30 +       struct platform_device *pdev;
  31 +       struct platform_device *spi_pdev;
  32 +       struct spi_board_info boardinfo;
  33 +};
  34 +
  35 +
  36 +MODULE_DESCRIPTION("GPIO based MMC driver");
  37 +MODULE_AUTHOR("Michael Buesch");
  38 +MODULE_LICENSE("GPL");
  39 +
  40 +
  41 +static int gpiommc_boardinfo_setup(struct spi_board_info *bi,
  42 +                                  struct spi_master *master,
  43 +                                  void *data)
  44 +{
  45 +       struct gpiommc_device *d = data;
  46 +       struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
  47 +
  48 +       /* Bind the SPI master to the MMC-SPI host driver. */
  49 +       strlcpy(bi->modalias, "mmc_spi", sizeof(bi->modalias));
  50 +
  51 +       bi->max_speed_hz = pdata->max_bus_speed;
  52 +       bi->bus_num = master->bus_num;
  53 +       bi->mode = pdata->mode;
  54 +
  55 +       return 0;
  56 +}
  57 +
  58 +static int gpiommc_probe(struct platform_device *pdev)
  59 +{
  60 +       struct gpiommc_platform_data *mmc_pdata = pdev->dev.platform_data;
  61 +       struct spi_gpio_platform_data spi_pdata;
  62 +       struct gpiommc_device *d;
  63 +       int err;
  64 +
  65 +       err = -ENXIO;
  66 +       if (!mmc_pdata)
  67 +               goto error;
  68 +
  69 +#ifdef CONFIG_MMC_SPI_MODULE
  70 +       err = request_module("mmc_spi");
  71 +       if (err) {
  72 +               printk(KERN_WARNING PFX
  73 +                      "Failed to request mmc_spi module.\n");
  74 +       }
  75 +#endif /* CONFIG_MMC_SPI_MODULE */
  76 +
  77 +       /* Allocate the GPIO-MMC device */
  78 +       err = -ENOMEM;
  79 +       d = kzalloc(sizeof(*d), GFP_KERNEL);
  80 +       if (!d)
  81 +               goto error;
  82 +       d->pdev = pdev;
  83 +
  84 +       /* Create the SPI-GPIO device */
  85 +       d->spi_pdev = platform_device_alloc(SPI_GPIO_PLATDEV_NAME,
  86 +                                           spi_gpio_next_id());
  87 +       if (!d->spi_pdev)
  88 +               goto err_free_d;
  89 +
  90 +       memset(&spi_pdata, 0, sizeof(spi_pdata));
  91 +       spi_pdata.pin_clk = mmc_pdata->pins.gpio_clk;
  92 +       spi_pdata.pin_miso = mmc_pdata->pins.gpio_do;
  93 +       spi_pdata.pin_mosi = mmc_pdata->pins.gpio_di;
  94 +       spi_pdata.pin_cs = mmc_pdata->pins.gpio_cs;
  95 +       spi_pdata.cs_activelow = mmc_pdata->pins.cs_activelow;
  96 +       spi_pdata.no_spi_delay = mmc_pdata->no_spi_delay;
  97 +       spi_pdata.boardinfo_setup = gpiommc_boardinfo_setup;
  98 +       spi_pdata.boardinfo_setup_data = d;
  99 +
 100 +       err = platform_device_add_data(d->spi_pdev, &spi_pdata,
 101 +                                      sizeof(spi_pdata));
 102 +       if (err)
 103 +               goto err_free_pdev;
 104 +       err = platform_device_add(d->spi_pdev);
 105 +       if (err)
 106 +               goto err_free_pdata;
 107 +       platform_set_drvdata(pdev, d);
 108 +
 109 +       printk(KERN_INFO PFX "MMC-Card \"%s\" "
 110 +              "attached to GPIO pins di=%u, do=%u, clk=%u, cs=%u\n",
 111 +              mmc_pdata->name, mmc_pdata->pins.gpio_di,
 112 +              mmc_pdata->pins.gpio_do,
 113 +              mmc_pdata->pins.gpio_clk,
 114 +              mmc_pdata->pins.gpio_cs);
 115 +
 116 +       return 0;
 117 +
 118 +err_free_pdata:
 119 +       kfree(d->spi_pdev->dev.platform_data);
 120 +       d->spi_pdev->dev.platform_data = NULL;
 121 +err_free_pdev:
 122 +       platform_device_put(d->spi_pdev);
 123 +err_free_d:
 124 +       kfree(d);
 125 +error:
 126 +       return err;
 127 +}
 128 +
 129 +static int gpiommc_remove(struct platform_device *pdev)
 130 +{
 131 +       struct gpiommc_device *d = platform_get_drvdata(pdev);
 132 +       struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
 133 +
 134 +       platform_device_unregister(d->spi_pdev);
 135 +       printk(KERN_INFO PFX "GPIO based MMC-Card \"%s\" removed\n",
 136 +              pdata->name);
 137 +       platform_device_put(d->spi_pdev);
 138 +
 139 +       return 0;
 140 +}
 141 +
 142 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 143 +
 144 +/* A device that was created through configfs */
 145 +struct gpiommc_configfs_device {
 146 +       struct config_item item;
 147 +       /* The platform device, after registration. */
 148 +       struct platform_device *pdev;
 149 +       /* The configuration */
 150 +       struct gpiommc_platform_data pdata;
 151 +};
 152 +
 153 +#define GPIO_INVALID   -1
 154 +
 155 +static inline bool gpiommc_is_registered(struct gpiommc_configfs_device *dev)
 156 +{
 157 +       return (dev->pdev != NULL);
 158 +}
 159 +
 160 +static inline struct gpiommc_configfs_device *ci_to_gpiommc(struct config_item *item)
 161 +{
 162 +       return item ? container_of(item, struct gpiommc_configfs_device, item) : NULL;
 163 +}
 164 +
 165 +static struct configfs_attribute gpiommc_attr_DI = {
 166 +       .ca_owner = THIS_MODULE,
 167 +       .ca_name = "gpio_data_in",
 168 +       .ca_mode = S_IRUGO | S_IWUSR,
 169 +};
 170 +
 171 +static struct configfs_attribute gpiommc_attr_DO = {
 172 +       .ca_owner = THIS_MODULE,
 173 +       .ca_name = "gpio_data_out",
 174 +       .ca_mode = S_IRUGO | S_IWUSR,
 175 +};
 176 +
 177 +static struct configfs_attribute gpiommc_attr_CLK = {
 178 +       .ca_owner = THIS_MODULE,
 179 +       .ca_name = "gpio_clock",
 180 +       .ca_mode = S_IRUGO | S_IWUSR,
 181 +};
 182 +
 183 +static struct configfs_attribute gpiommc_attr_CS = {
 184 +       .ca_owner = THIS_MODULE,
 185 +       .ca_name = "gpio_chipselect",
 186 +       .ca_mode = S_IRUGO | S_IWUSR,
 187 +};
 188 +
 189 +static struct configfs_attribute gpiommc_attr_CS_activelow = {
 190 +       .ca_owner = THIS_MODULE,
 191 +       .ca_name = "gpio_chipselect_activelow",
 192 +       .ca_mode = S_IRUGO | S_IWUSR,
 193 +};
 194 +
 195 +static struct configfs_attribute gpiommc_attr_spimode = {
 196 +       .ca_owner = THIS_MODULE,
 197 +       .ca_name = "spi_mode",
 198 +       .ca_mode = S_IRUGO | S_IWUSR,
 199 +};
 200 +
 201 +static struct configfs_attribute gpiommc_attr_spidelay = {
 202 +       .ca_owner = THIS_MODULE,
 203 +       .ca_name = "spi_delay",
 204 +       .ca_mode = S_IRUGO | S_IWUSR,
 205 +};
 206 +
 207 +static struct configfs_attribute gpiommc_attr_max_bus_speed = {
 208 +       .ca_owner = THIS_MODULE,
 209 +       .ca_name = "max_bus_speed",
 210 +       .ca_mode = S_IRUGO | S_IWUSR,
 211 +};
 212 +
 213 +static struct configfs_attribute gpiommc_attr_register = {
 214 +       .ca_owner = THIS_MODULE,
 215 +       .ca_name = "register",
 216 +       .ca_mode = S_IRUGO | S_IWUSR,
 217 +};
 218 +
 219 +static struct configfs_attribute *gpiommc_config_attrs[] = {
 220 +       &gpiommc_attr_DI,
 221 +       &gpiommc_attr_DO,
 222 +       &gpiommc_attr_CLK,
 223 +       &gpiommc_attr_CS,
 224 +       &gpiommc_attr_CS_activelow,
 225 +       &gpiommc_attr_spimode,
 226 +       &gpiommc_attr_spidelay,
 227 +       &gpiommc_attr_max_bus_speed,
 228 +       &gpiommc_attr_register,
 229 +       NULL,
 230 +};
 231 +
 232 +static ssize_t gpiommc_config_attr_show(struct config_item *item,
 233 +                                       struct configfs_attribute *attr,
 234 +                                       char *page)
 235 +{
 236 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 237 +       ssize_t count = 0;
 238 +       unsigned int gpio;
 239 +       int err = 0;
 240 +
 241 +       if (attr == &gpiommc_attr_DI) {
 242 +               gpio = dev->pdata.pins.gpio_di;
 243 +               if (gpio == GPIO_INVALID)
 244 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 245 +               else
 246 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 247 +               goto out;
 248 +       }
 249 +       if (attr == &gpiommc_attr_DO) {
 250 +               gpio = dev->pdata.pins.gpio_do;
 251 +               if (gpio == GPIO_INVALID)
 252 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 253 +               else
 254 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 255 +               goto out;
 256 +       }
 257 +       if (attr == &gpiommc_attr_CLK) {
 258 +               gpio = dev->pdata.pins.gpio_clk;
 259 +               if (gpio == GPIO_INVALID)
 260 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 261 +               else
 262 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 263 +               goto out;
 264 +       }
 265 +       if (attr == &gpiommc_attr_CS) {
 266 +               gpio = dev->pdata.pins.gpio_cs;
 267 +               if (gpio == GPIO_INVALID)
 268 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 269 +               else
 270 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 271 +               goto out;
 272 +       }
 273 +       if (attr == &gpiommc_attr_CS_activelow) {
 274 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 275 +                                dev->pdata.pins.cs_activelow);
 276 +               goto out;
 277 +       }
 278 +       if (attr == &gpiommc_attr_spimode) {
 279 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 280 +                                dev->pdata.mode);
 281 +               goto out;
 282 +       }
 283 +       if (attr == &gpiommc_attr_spidelay) {
 284 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 285 +                                !dev->pdata.no_spi_delay);
 286 +               goto out;
 287 +       }
 288 +       if (attr == &gpiommc_attr_max_bus_speed) {
 289 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 290 +                                dev->pdata.max_bus_speed);
 291 +               goto out;
 292 +       }
 293 +       if (attr == &gpiommc_attr_register) {
 294 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 295 +                                gpiommc_is_registered(dev));
 296 +               goto out;
 297 +       }
 298 +       WARN_ON(1);
 299 +       err = -ENOSYS;
 300 +out:
 301 +       return err ? err : count;
 302 +}
 303 +
 304 +static int gpiommc_do_register(struct gpiommc_configfs_device *dev,
 305 +                              const char *name)
 306 +{
 307 +       int err;
 308 +
 309 +       if (gpiommc_is_registered(dev))
 310 +               return 0;
 311 +
 312 +       if (!gpio_is_valid(dev->pdata.pins.gpio_di) ||
 313 +           !gpio_is_valid(dev->pdata.pins.gpio_do) ||
 314 +           !gpio_is_valid(dev->pdata.pins.gpio_clk) ||
 315 +           !gpio_is_valid(dev->pdata.pins.gpio_cs)) {
 316 +               printk(KERN_ERR PFX
 317 +                      "configfs: Invalid GPIO pin number(s)\n");
 318 +               return -EINVAL;
 319 +       }
 320 +
 321 +       strlcpy(dev->pdata.name, name,
 322 +               sizeof(dev->pdata.name));
 323 +
 324 +       dev->pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME,
 325 +                                         gpiommc_next_id());
 326 +       if (!dev->pdev)
 327 +               return -ENOMEM;
 328 +       err = platform_device_add_data(dev->pdev, &dev->pdata,
 329 +                                      sizeof(dev->pdata));
 330 +       if (err) {
 331 +               platform_device_put(dev->pdev);
 332 +               return err;
 333 +       }
 334 +       err = platform_device_add(dev->pdev);
 335 +       if (err) {
 336 +               platform_device_put(dev->pdev);
 337 +               return err;
 338 +       }
 339 +
 340 +       return 0;
 341 +}
 342 +
 343 +static void gpiommc_do_unregister(struct gpiommc_configfs_device *dev)
 344 +{
 345 +       if (!gpiommc_is_registered(dev))
 346 +               return;
 347 +
 348 +       platform_device_unregister(dev->pdev);
 349 +       dev->pdev = NULL;
 350 +}
 351 +
 352 +static ssize_t gpiommc_config_attr_store(struct config_item *item,
 353 +                                        struct configfs_attribute *attr,
 354 +                                        const char *page, size_t count)
 355 +{
 356 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 357 +       int err = -EINVAL;
 358 +       unsigned long data;
 359 +
 360 +       if (attr == &gpiommc_attr_register) {
 361 +               err = strict_strtoul(page, 10, &data);
 362 +               if (err)
 363 +                       goto out;
 364 +               err = -EINVAL;
 365 +               if (data == 1)
 366 +                       err = gpiommc_do_register(dev, item->ci_name);
 367 +               if (data == 0) {
 368 +                       gpiommc_do_unregister(dev);
 369 +                       err = 0;
 370 +               }
 371 +               goto out;
 372 +       }
 373 +
 374 +       if (gpiommc_is_registered(dev)) {
 375 +               /* The rest of the config parameters can only be set
 376 +                * as long as the device is not registered, yet. */
 377 +               err = -EBUSY;
 378 +               goto out;
 379 +       }
 380 +
 381 +       if (attr == &gpiommc_attr_DI) {
 382 +               err = strict_strtoul(page, 10, &data);
 383 +               if (err)
 384 +                       goto out;
 385 +               err = -EINVAL;
 386 +               if (!gpio_is_valid(data))
 387 +                       goto out;
 388 +               dev->pdata.pins.gpio_di = data;
 389 +               err = 0;
 390 +               goto out;
 391 +       }
 392 +       if (attr == &gpiommc_attr_DO) {
 393 +               err = strict_strtoul(page, 10, &data);
 394 +               if (err)
 395 +                       goto out;
 396 +               err = -EINVAL;
 397 +               if (!gpio_is_valid(data))
 398 +                       goto out;
 399 +               dev->pdata.pins.gpio_do = data;
 400 +               err = 0;
 401 +               goto out;
 402 +       }
 403 +       if (attr == &gpiommc_attr_CLK) {
 404 +               err = strict_strtoul(page, 10, &data);
 405 +               if (err)
 406 +                       goto out;
 407 +               err = -EINVAL;
 408 +               if (!gpio_is_valid(data))
 409 +                       goto out;
 410 +               dev->pdata.pins.gpio_clk = data;
 411 +               err = 0;
 412 +               goto out;
 413 +       }
 414 +       if (attr == &gpiommc_attr_CS) {
 415 +               err = strict_strtoul(page, 10, &data);
 416 +               if (err)
 417 +                       goto out;
 418 +               err = -EINVAL;
 419 +               if (!gpio_is_valid(data))
 420 +                       goto out;
 421 +               dev->pdata.pins.gpio_cs = data;
 422 +               err = 0;
 423 +               goto out;
 424 +       }
 425 +       if (attr == &gpiommc_attr_CS_activelow) {
 426 +               err = strict_strtoul(page, 10, &data);
 427 +               if (err)
 428 +                       goto out;
 429 +               err = -EINVAL;
 430 +               if (data != 0 && data != 1)
 431 +                       goto out;
 432 +               dev->pdata.pins.cs_activelow = data;
 433 +               err = 0;
 434 +               goto out;
 435 +       }
 436 +       if (attr == &gpiommc_attr_spimode) {
 437 +               err = strict_strtoul(page, 10, &data);
 438 +               if (err)
 439 +                       goto out;
 440 +               err = -EINVAL;
 441 +               switch (data) {
 442 +               case 0:
 443 +                       dev->pdata.mode = SPI_MODE_0;
 444 +                       break;
 445 +               case 1:
 446 +                       dev->pdata.mode = SPI_MODE_1;
 447 +                       break;
 448 +               case 2:
 449 +                       dev->pdata.mode = SPI_MODE_2;
 450 +                       break;
 451 +               case 3:
 452 +                       dev->pdata.mode = SPI_MODE_3;
 453 +                       break;
 454 +               default:
 455 +                       goto out;
 456 +               }
 457 +               err = 0;
 458 +               goto out;
 459 +       }
 460 +       if (attr == &gpiommc_attr_spidelay) {
 461 +               err = strict_strtoul(page, 10, &data);
 462 +               if (err)
 463 +                       goto out;
 464 +               err = -EINVAL;
 465 +               if (data != 0 && data != 1)
 466 +                       goto out;
 467 +               dev->pdata.no_spi_delay = !data;
 468 +               err = 0;
 469 +               goto out;
 470 +       }
 471 +       if (attr == &gpiommc_attr_max_bus_speed) {
 472 +               err = strict_strtoul(page, 10, &data);
 473 +               if (err)
 474 +                       goto out;
 475 +               err = -EINVAL;
 476 +               if (data > UINT_MAX)
 477 +                       goto out;
 478 +               dev->pdata.max_bus_speed = data;
 479 +               err = 0;
 480 +               goto out;
 481 +       }
 482 +       WARN_ON(1);
 483 +       err = -ENOSYS;
 484 +out:
 485 +       return err ? err : count;
 486 +}
 487 +
 488 +static void gpiommc_config_item_release(struct config_item *item)
 489 +{
 490 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 491 +
 492 +       kfree(dev);
 493 +}
 494 +
 495 +static struct configfs_item_operations gpiommc_config_item_ops = {
 496 +       .release                = gpiommc_config_item_release,
 497 +       .show_attribute         = gpiommc_config_attr_show,
 498 +       .store_attribute        = gpiommc_config_attr_store,
 499 +};
 500 +
 501 +static struct config_item_type gpiommc_dev_ci_type = {
 502 +       .ct_item_ops    = &gpiommc_config_item_ops,
 503 +       .ct_attrs       = gpiommc_config_attrs,
 504 +       .ct_owner       = THIS_MODULE,
 505 +};
 506 +
 507 +static struct config_item *gpiommc_make_item(struct config_group *group,
 508 +                                            const char *name)
 509 +{
 510 +       struct gpiommc_configfs_device *dev;
 511 +
 512 +       if (strlen(name) > GPIOMMC_MAX_NAMELEN) {
 513 +               printk(KERN_ERR PFX "configfs: device name too long\n");
 514 +               return NULL;
 515 +       }
 516 +
 517 +       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 518 +       if (!dev)
 519 +               return NULL;
 520 +
 521 +       config_item_init_type_name(&dev->item, name,
 522 +                                  &gpiommc_dev_ci_type);
 523 +
 524 +       /* Assign default configuration */
 525 +       dev->pdata.pins.gpio_di = GPIO_INVALID;
 526 +       dev->pdata.pins.gpio_do = GPIO_INVALID;
 527 +       dev->pdata.pins.gpio_clk = GPIO_INVALID;
 528 +       dev->pdata.pins.gpio_cs = GPIO_INVALID;
 529 +       dev->pdata.pins.cs_activelow = 1;
 530 +       dev->pdata.mode = SPI_MODE_0;
 531 +       dev->pdata.no_spi_delay = 0;
 532 +       dev->pdata.max_bus_speed = 5000000; /* 5 MHz */
 533 +
 534 +       return &(dev->item);
 535 +}
 536 +
 537 +static void gpiommc_drop_item(struct config_group *group,
 538 +                             struct config_item *item)
 539 +{
 540 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 541 +
 542 +       gpiommc_do_unregister(dev);
 543 +       kfree(dev);
 544 +}
 545 +
 546 +static struct configfs_group_operations gpiommc_ct_group_ops = {
 547 +       .make_item      = gpiommc_make_item,
 548 +       .drop_item      = gpiommc_drop_item,
 549 +};
 550 +
 551 +static struct config_item_type gpiommc_ci_type = {
 552 +       .ct_group_ops   = &gpiommc_ct_group_ops,
 553 +       .ct_owner       = THIS_MODULE,
 554 +};
 555 +
 556 +static struct configfs_subsystem gpiommc_subsys = {
 557 +       .su_group = {
 558 +               .cg_item = {
 559 +                       .ci_namebuf = GPIOMMC_PLATDEV_NAME,
 560 +                       .ci_type = &gpiommc_ci_type,
 561 +               },
 562 +       },
 563 +       .su_mutex = __MUTEX_INITIALIZER(gpiommc_subsys.su_mutex),
 564 +};
 565 +
 566 +#endif /* CONFIG_GPIOMMC_CONFIGFS */
 567 +
 568 +static struct platform_driver gpiommc_plat_driver = {
 569 +       .probe  = gpiommc_probe,
 570 +       .remove = gpiommc_remove,
 571 +       .driver = {
 572 +               .name   = GPIOMMC_PLATDEV_NAME,
 573 +               .owner  = THIS_MODULE,
 574 +       },
 575 +};
 576 +
 577 +int gpiommc_next_id(void)
 578 +{
 579 +       static atomic_t counter = ATOMIC_INIT(-1);
 580 +
 581 +       return atomic_inc_return(&counter);
 582 +}
 583 +EXPORT_SYMBOL(gpiommc_next_id);
 584 +
 585 +static int __init gpiommc_modinit(void)
 586 +{
 587 +       int err;
 588 +
 589 +       err = platform_driver_register(&gpiommc_plat_driver);
 590 +       if (err)
 591 +               return err;
 592 +
 593 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 594 +       config_group_init(&gpiommc_subsys.su_group);
 595 +       err = configfs_register_subsystem(&gpiommc_subsys);
 596 +       if (err) {
 597 +               platform_driver_unregister(&gpiommc_plat_driver);
 598 +               return err;
 599 +       }
 600 +#endif /* CONFIG_GPIOMMC_CONFIGFS */
 601 +
 602 +       return 0;
 603 +}
 604 +module_init(gpiommc_modinit);
 605 +
 606 +static void __exit gpiommc_modexit(void)
 607 +{
 608 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 609 +       configfs_unregister_subsystem(&gpiommc_subsys);
 610 +#endif
 611 +       platform_driver_unregister(&gpiommc_plat_driver);
 612 +}
 613 +module_exit(gpiommc_modexit);
 614 Index: linux-2.6.28.2/drivers/mmc/host/Kconfig
 615 ===================================================================
 616 --- linux-2.6.28.2.orig/drivers/mmc/host/Kconfig        2009-02-10 17:16:15.000000000 +0100
 617 +++ linux-2.6.28.2/drivers/mmc/host/Kconfig     2009-02-10 17:16:16.000000000 +0100
 618 @@ -192,3 +192,28 @@ config MMC_TMIO
 619         help
 620           This provides support for the SD/MMC cell found in TC6393XB,
 621           T7L66XB and also ipaq ASIC3
 622 +
 623 +config GPIOMMC
 624 +       tristate "MMC/SD over GPIO-based SPI"
 625 +       depends on MMC && MMC_SPI && SPI_GPIO
 626 +       help
 627 +         This driver hooks up the mmc_spi and spi_gpio modules so that
 628 +         MMC/SD cards can be used on a GPIO based bus by bitbanging
 629 +         the SPI protocol in software.
 630 +
 631 +         This driver provides a configfs interface to dynamically create
 632 +         and destroy GPIO-based MMC/SD card devices. It also provides
 633 +         a platform device interface API.
 634 +         See Documentation/gpiommc.txt for details.
 635 +
 636 +         The module will be called gpiommc.
 637 +
 638 +         If unsure, say N.
 639 +
 640 +config GPIOMMC_CONFIGFS
 641 +       bool
 642 +       depends on GPIOMMC && CONFIGFS_FS
 643 +       default y
 644 +       help
 645 +         This option automatically enables configfs support for gpiommc
 646 +         if configfs is available.
 647 Index: linux-2.6.28.2/drivers/mmc/host/Makefile
 648 ===================================================================
 649 --- linux-2.6.28.2.orig/drivers/mmc/host/Makefile       2009-02-10 17:16:15.000000000 +0100
 650 +++ linux-2.6.28.2/drivers/mmc/host/Makefile    2009-02-10 17:16:16.000000000 +0100
 651 @@ -22,4 +22,5 @@ obj-$(CONFIG_MMC_SPI)         += mmc_spi.o
 652  obj-$(CONFIG_MMC_S3C)          += s3cmci.o
 653  obj-$(CONFIG_MMC_SDRICOH_CS)   += sdricoh_cs.o
 654  obj-$(CONFIG_MMC_TMIO)         += tmio_mmc.o
 655 +obj-$(CONFIG_GPIOMMC)          += gpiommc.o
 656
 657 Index: linux-2.6.28.2/include/linux/mmc/gpiommc.h
 658 ===================================================================
 659 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
 660 +++ linux-2.6.28.2/include/linux/mmc/gpiommc.h  2009-02-10 17:16:16.000000000 +0100
 661 @@ -0,0 +1,71 @@
 662 +/*
 663 + * Device driver for MMC/SD cards driven over a GPIO bus.
 664 + *
 665 + * Copyright (c) 2008 Michael Buesch
 666 + *
 667 + * Licensed under the GNU/GPL version 2.
 668 + */
 669 +#ifndef LINUX_GPIOMMC_H_
 670 +#define LINUX_GPIOMMC_H_
 671 +
 672 +#include <linux/types.h>
 673 +
 674 +
 675 +#define GPIOMMC_MAX_NAMELEN            15
 676 +#define GPIOMMC_MAX_NAMELEN_STR                __stringify(GPIOMMC_MAX_NAMELEN)
 677 +
 678 +/**
 679 + * struct gpiommc_pins - Hardware pin assignments
 680 + *
 681 + * @gpio_di: The GPIO number of the DATA IN pin
 682 + * @gpio_do: The GPIO number of the DATA OUT pin
 683 + * @gpio_clk: The GPIO number of the CLOCK pin
 684 + * @gpio_cs: The GPIO number of the CHIPSELECT pin
 685 + * @cs_activelow: If true, the chip is considered selected if @gpio_cs is low.
 686 + */
 687 +struct gpiommc_pins {
 688 +       unsigned int gpio_di;
 689 +       unsigned int gpio_do;
 690 +       unsigned int gpio_clk;
 691 +       unsigned int gpio_cs;
 692 +       bool cs_activelow;
 693 +};
 694 +
 695 +/**
 696 + * struct gpiommc_platform_data - Platform data for a MMC-over-SPI-GPIO device.
 697 + *
 698 + * @name: The unique name string of the device.
 699 + * @pins: The hardware pin assignments.
 700 + * @mode: The hardware mode. This is either SPI_MODE_0,
 701 + *        SPI_MODE_1, SPI_MODE_2 or SPI_MODE_3. See the SPI documentation.
 702 + * @no_spi_delay: Do not use delays in the lowlevel SPI bitbanging code.
 703 + *                This is not standards compliant, but may be required for some
 704 + *                embedded machines to gain reasonable speed.
 705 + * @max_bus_speed: The maximum speed of the SPI bus, in Hertz.
 706 + */
 707 +struct gpiommc_platform_data {
 708 +       char name[GPIOMMC_MAX_NAMELEN + 1];
 709 +       struct gpiommc_pins pins;
 710 +       u8 mode;
 711 +       bool no_spi_delay;
 712 +       unsigned int max_bus_speed;
 713 +};
 714 +
 715 +/**
 716 + * GPIOMMC_PLATDEV_NAME - The platform device name string.
 717 + *
 718 + * The name string that has to be used for platform_device_alloc
 719 + * when allocating a gpiommc device.
 720 + */
 721 +#define GPIOMMC_PLATDEV_NAME   "gpiommc"
 722 +
 723 +/**
 724 + * gpiommc_next_id - Get another platform device ID number.
 725 + *
 726 + * This returns the next platform device ID number that has to be used
 727 + * for platform_device_alloc. The ID is opaque and should not be used for
 728 + * anything else.
 729 + */
 730 +int gpiommc_next_id(void);
 731 +
 732 +#endif /* LINUX_GPIOMMC_H_ */
 733 Index: linux-2.6.28.2/Documentation/gpiommc.txt
 734 ===================================================================
 735 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
 736 +++ linux-2.6.28.2/Documentation/gpiommc.txt    2009-02-10 17:16:16.000000000 +0100
 737 @@ -0,0 +1,97 @@
 738 +GPIOMMC - Driver for an MMC/SD card on a bitbanging GPIO SPI bus
 739 +================================================================
 740 +
 741 +The gpiommc module hooks up the mmc_spi and spi_gpio modules for running an
 742 +MMC or SD card on GPIO pins.
 743 +
 744 +Two interfaces for registering a new MMC/SD card device are provided:
 745 +A static platform-device based mechanism and a dynamic configfs based interface.
 746 +
 747 +
 748 +Registering devices via platform-device
 749 +=======================================
 750 +
 751 +The platform-device interface is used for registering MMC/SD devices that are
 752 +part of the hardware platform. This is most useful only for embedded machines
 753 +with MMC/SD devices statically connected to the platform GPIO bus.
 754 +
 755 +The data structures are declared in <linux/mmc/gpiommc.h>.
 756 +
 757 +To register a new device, define an instance of struct gpiommc_platform_data.
 758 +This structure holds any information about how the device is hooked up to the
 759 +GPIO pins and what hardware modes the device supports. See the docbook-style
 760 +documentation in the header file for more information on the struct fields.
 761 +
 762 +Then allocate a new instance of a platform device by doing:
 763 +
 764 +       pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME, gpiommc_next_id());
 765 +
 766 +This will allocate the platform device data structures and hook it up to the
 767 +gpiommc driver.
 768 +Then add the gpiommc_platform_data to the platform device.
 769 +
 770 +       err = platform_device_add_data(pdev, pdata, sizeof(struct gpiommc_platform_data));
 771 +
 772 +You may free the local instance of struct gpiommc_platform_data now. (So the
 773 +struct may be allocated on the stack, too).
 774 +Now simply register the platform device.
 775 +
 776 +       err = platform_device_add(pdev);
 777 +
 778 +Done. The gpiommc probe routine will be invoked now and you should see a kernel
 779 +log message for the added device.
 780 +
 781 +
 782 +Registering devices via configfs
 783 +================================
 784 +
 785 +MMC/SD cards connected via GPIO often are a pretty dynamic thing, as for example
 786 +selfmade hacks for soldering an MMC/SD card to standard GPIO pins on embedded
 787 +hardware are a common situation.
 788 +So we provide a dynamic interface to conveniently handle adding and removing
 789 +devices from userspace, without the need to recompile the kernel.
 790 +
 791 +The "gpiommc" subdirectory at the configfs mountpoint is used for handling
 792 +the dynamic configuration.
 793 +
 794 +To create a new device, it must first be allocated with mkdir.
 795 +The following command will allocate a device named "my_mmc":
 796 +       mkdir /config/gpiommc/my_mmc
 797 +
 798 +There are several configuration files available in the new
 799 +/config/gpiommc/my_mmc/ directory:
 800 +
 801 +gpio_data_in                   = The SPI data-IN GPIO pin number.
 802 +gpio_data_out                  = The SPI data-OUT GPIO pin number.
 803 +gpio_clock                     = The SPI Clock GPIO pin number.
 804 +gpio_chipselect                        = The SPI Chipselect GPIO pin number.
 805 +gpio_chipselect_activelow      = Boolean. If 0, Chipselect is active-HIGH.
 806 +                                 If 1, Chipselect is active-LOW.
 807 +spi_mode                       = The SPI data mode. Can be 0-3.
 808 +spi_delay                      = Enable all delays in the lowlevel bitbanging.
 809 +max_bus_speed                  = The maximum SPI bus speed. In Hertz.
 810 +
 811 +register                       = Not a configuration parameter.
 812 +                                 Used to register the configured card
 813 +                                 with the kernel.
 814 +
 815 +The device must first get configured and then registered by writing "1" to
 816 +the "register" file.
 817 +The configuration parameters "gpio_data_in", "gpio_data_out", "gpio_clock"
 818 +and "gpio_chipselect" are essential and _must_ be configured before writing
 819 +"1" to the "register" file. The registration will fail, otherwise.
 820 +
 821 +The default values for the other parameters are:
 822 +gpio_chipselect_activelow      = 1             (CS active-LOW)
 823 +spi_mode                       = 0             (SPI_MODE_0)
 824 +spi_delay                      = 1             (enabled)
 825 +max_bus_speed                  = 5000000       (5 Mhz)
 826 +
 827 +Configuration values can not be changed after registration. To unregister
 828 +the device, write a "0" to the "register" file. The configuration can be
 829 +changed again after unregistering.
 830 +
 831 +To completely remove the device, simply rmdir the directory
 832 +(/config/gpiommc/my_mmc in this example).
 833 +There's no need to first unregister the device before removing it. That will
 834 +be done automatically.
 835 Index: linux-2.6.28.2/MAINTAINERS
 836 ===================================================================
 837 --- linux-2.6.28.2.orig/MAINTAINERS     2009-02-10 17:16:15.000000000 +0100
 838 +++ linux-2.6.28.2/MAINTAINERS  2009-02-10 17:16:16.000000000 +0100
 839 @@ -1911,6 +1911,11 @@ W:       http://moinejf.free.fr
 840  L:     video4linux-list@redhat.com
 841  S:     Maintained
 842
 843 +GPIOMMC DRIVER
 844 +P:     Michael Buesch
 845 +M:     mb@bu3sch.de
 846 +S:     Maintained
 847 +
 848  HARDWARE MONITORING
 849  L:     lm-sensors@lm-sensors.org
 850  W:     http://www.lm-sensors.org/