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

   1 --- /dev/null
   2 +++ b/drivers/mmc/host/gpiommc.c
   3 @@ -0,0 +1,608 @@
   4 +/*
   5 + * Driver an MMC/SD card on a bitbanging GPIO SPI bus.
   6 + * This module hooks up the mmc_spi and spi_gpio modules and also
   7 + * provides a configfs interface.
   8 + *
   9 + * Copyright 2008 Michael Buesch <mb@bu3sch.de>
  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_AUTHOR("Michael Buesch");
  36 +MODULE_LICENSE("GPL");
  37 +
  38 +
  39 +static int gpiommc_boardinfo_setup(struct spi_board_info *bi,
  40 +                                  struct spi_master *master,
  41 +                                  void *data)
  42 +{
  43 +       struct gpiommc_device *d = data;
  44 +       struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
  45 +
  46 +       /* Bind the SPI master to the MMC-SPI host driver. */
  47 +       strlcpy(bi->modalias, "mmc_spi", sizeof(bi->modalias));
  48 +
  49 +       bi->max_speed_hz = pdata->max_bus_speed;
  50 +       bi->bus_num = master->bus_num;
  51 +       bi->mode = pdata->mode;
  52 +
  53 +       return 0;
  54 +}
  55 +
  56 +static int gpiommc_probe(struct platform_device *pdev)
  57 +{
  58 +       struct gpiommc_platform_data *mmc_pdata = pdev->dev.platform_data;
  59 +       struct spi_gpio_platform_data spi_pdata;
  60 +       struct gpiommc_device *d;
  61 +       int err;
  62 +
  63 +       err = -ENXIO;
  64 +       if (!mmc_pdata)
  65 +               goto error;
  66 +
  67 +#ifdef CONFIG_MMC_SPI_MODULE
  68 +       err = request_module("mmc_spi");
  69 +       if (err) {
  70 +               printk(KERN_WARNING PFX
  71 +                      "Failed to request mmc_spi module.\n");
  72 +       }
  73 +#endif /* CONFIG_MMC_SPI_MODULE */
  74 +
  75 +       /* Allocate the GPIO-MMC device */
  76 +       err = -ENOMEM;
  77 +       d = kzalloc(sizeof(*d), GFP_KERNEL);
  78 +       if (!d)
  79 +               goto error;
  80 +       d->pdev = pdev;
  81 +
  82 +       /* Create the SPI-GPIO device */
  83 +       d->spi_pdev = platform_device_alloc(SPI_GPIO_PLATDEV_NAME,
  84 +                                           spi_gpio_next_id());
  85 +       if (!d->spi_pdev)
  86 +               goto err_free_d;
  87 +
  88 +       memset(&spi_pdata, 0, sizeof(spi_pdata));
  89 +       spi_pdata.pin_clk = mmc_pdata->pins.gpio_clk;
  90 +       spi_pdata.pin_miso = mmc_pdata->pins.gpio_do;
  91 +       spi_pdata.pin_mosi = mmc_pdata->pins.gpio_di;
  92 +       spi_pdata.pin_cs = mmc_pdata->pins.gpio_cs;
  93 +       spi_pdata.cs_activelow = mmc_pdata->pins.cs_activelow;
  94 +       spi_pdata.no_spi_delay = mmc_pdata->no_spi_delay;
  95 +       spi_pdata.boardinfo_setup = gpiommc_boardinfo_setup;
  96 +       spi_pdata.boardinfo_setup_data = d;
  97 +
  98 +       err = platform_device_add_data(d->spi_pdev, &spi_pdata,
  99 +                                      sizeof(spi_pdata));
 100 +       if (err)
 101 +               goto err_free_pdev;
 102 +       err = platform_device_add(d->spi_pdev);
 103 +       if (err)
 104 +               goto err_free_pdata;
 105 +       platform_set_drvdata(pdev, d);
 106 +
 107 +       printk(KERN_INFO PFX "MMC-Card \"%s\" "
 108 +              "attached to GPIO pins di=%u, do=%u, clk=%u, cs=%u\n",
 109 +              mmc_pdata->name, mmc_pdata->pins.gpio_di,
 110 +              mmc_pdata->pins.gpio_do,
 111 +              mmc_pdata->pins.gpio_clk,
 112 +              mmc_pdata->pins.gpio_cs);
 113 +
 114 +       return 0;
 115 +
 116 +err_free_pdata:
 117 +       kfree(d->spi_pdev->dev.platform_data);
 118 +       d->spi_pdev->dev.platform_data = NULL;
 119 +err_free_pdev:
 120 +       platform_device_put(d->spi_pdev);
 121 +err_free_d:
 122 +       kfree(d);
 123 +error:
 124 +       return err;
 125 +}
 126 +
 127 +static int gpiommc_remove(struct platform_device *pdev)
 128 +{
 129 +       struct gpiommc_device *d = platform_get_drvdata(pdev);
 130 +       struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
 131 +
 132 +       platform_device_unregister(d->spi_pdev);
 133 +       printk(KERN_INFO PFX "GPIO based MMC-Card \"%s\" removed\n",
 134 +              pdata->name);
 135 +       platform_device_put(d->spi_pdev);
 136 +
 137 +       return 0;
 138 +}
 139 +
 140 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 141 +
 142 +/* A device that was created through configfs */
 143 +struct gpiommc_configfs_device {
 144 +       struct config_item item;
 145 +       /* The platform device, after registration. */
 146 +       struct platform_device *pdev;
 147 +       /* The configuration */
 148 +       struct gpiommc_platform_data pdata;
 149 +};
 150 +
 151 +#define GPIO_INVALID   -1
 152 +
 153 +static inline bool gpiommc_is_registered(struct gpiommc_configfs_device *dev)
 154 +{
 155 +       return (dev->pdev != NULL);
 156 +}
 157 +
 158 +static inline struct gpiommc_configfs_device *ci_to_gpiommc(struct config_item *item)
 159 +{
 160 +       return item ? container_of(item, struct gpiommc_configfs_device, item) : NULL;
 161 +}
 162 +
 163 +static struct configfs_attribute gpiommc_attr_DI = {
 164 +       .ca_owner = THIS_MODULE,
 165 +       .ca_name = "gpio_data_in",
 166 +       .ca_mode = S_IRUGO | S_IWUSR,
 167 +};
 168 +
 169 +static struct configfs_attribute gpiommc_attr_DO = {
 170 +       .ca_owner = THIS_MODULE,
 171 +       .ca_name = "gpio_data_out",
 172 +       .ca_mode = S_IRUGO | S_IWUSR,
 173 +};
 174 +
 175 +static struct configfs_attribute gpiommc_attr_CLK = {
 176 +       .ca_owner = THIS_MODULE,
 177 +       .ca_name = "gpio_clock",
 178 +       .ca_mode = S_IRUGO | S_IWUSR,
 179 +};
 180 +
 181 +static struct configfs_attribute gpiommc_attr_CS = {
 182 +       .ca_owner = THIS_MODULE,
 183 +       .ca_name = "gpio_chipselect",
 184 +       .ca_mode = S_IRUGO | S_IWUSR,
 185 +};
 186 +
 187 +static struct configfs_attribute gpiommc_attr_CS_activelow = {
 188 +       .ca_owner = THIS_MODULE,
 189 +       .ca_name = "gpio_chipselect_activelow",
 190 +       .ca_mode = S_IRUGO | S_IWUSR,
 191 +};
 192 +
 193 +static struct configfs_attribute gpiommc_attr_spimode = {
 194 +       .ca_owner = THIS_MODULE,
 195 +       .ca_name = "spi_mode",
 196 +       .ca_mode = S_IRUGO | S_IWUSR,
 197 +};
 198 +
 199 +static struct configfs_attribute gpiommc_attr_spidelay = {
 200 +       .ca_owner = THIS_MODULE,
 201 +       .ca_name = "spi_delay",
 202 +       .ca_mode = S_IRUGO | S_IWUSR,
 203 +};
 204 +
 205 +static struct configfs_attribute gpiommc_attr_max_bus_speed = {
 206 +       .ca_owner = THIS_MODULE,
 207 +       .ca_name = "max_bus_speed",
 208 +       .ca_mode = S_IRUGO | S_IWUSR,
 209 +};
 210 +
 211 +static struct configfs_attribute gpiommc_attr_register = {
 212 +       .ca_owner = THIS_MODULE,
 213 +       .ca_name = "register",
 214 +       .ca_mode = S_IRUGO | S_IWUSR,
 215 +};
 216 +
 217 +static struct configfs_attribute *gpiommc_config_attrs[] = {
 218 +       &gpiommc_attr_DI,
 219 +       &gpiommc_attr_DO,
 220 +       &gpiommc_attr_CLK,
 221 +       &gpiommc_attr_CS,
 222 +       &gpiommc_attr_CS_activelow,
 223 +       &gpiommc_attr_spimode,
 224 +       &gpiommc_attr_spidelay,
 225 +       &gpiommc_attr_max_bus_speed,
 226 +       &gpiommc_attr_register,
 227 +       NULL,
 228 +};
 229 +
 230 +static ssize_t gpiommc_config_attr_show(struct config_item *item,
 231 +                                       struct configfs_attribute *attr,
 232 +                                       char *page)
 233 +{
 234 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 235 +       ssize_t count = 0;
 236 +       unsigned int gpio;
 237 +       int err = 0;
 238 +
 239 +       if (attr == &gpiommc_attr_DI) {
 240 +               gpio = dev->pdata.pins.gpio_di;
 241 +               if (gpio == GPIO_INVALID)
 242 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 243 +               else
 244 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 245 +               goto out;
 246 +       }
 247 +       if (attr == &gpiommc_attr_DO) {
 248 +               gpio = dev->pdata.pins.gpio_do;
 249 +               if (gpio == GPIO_INVALID)
 250 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 251 +               else
 252 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 253 +               goto out;
 254 +       }
 255 +       if (attr == &gpiommc_attr_CLK) {
 256 +               gpio = dev->pdata.pins.gpio_clk;
 257 +               if (gpio == GPIO_INVALID)
 258 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 259 +               else
 260 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 261 +               goto out;
 262 +       }
 263 +       if (attr == &gpiommc_attr_CS) {
 264 +               gpio = dev->pdata.pins.gpio_cs;
 265 +               if (gpio == GPIO_INVALID)
 266 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 267 +               else
 268 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 269 +               goto out;
 270 +       }
 271 +       if (attr == &gpiommc_attr_CS_activelow) {
 272 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 273 +                                dev->pdata.pins.cs_activelow);
 274 +               goto out;
 275 +       }
 276 +       if (attr == &gpiommc_attr_spimode) {
 277 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 278 +                                dev->pdata.mode);
 279 +               goto out;
 280 +       }
 281 +       if (attr == &gpiommc_attr_spidelay) {
 282 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 283 +                                !dev->pdata.no_spi_delay);
 284 +               goto out;
 285 +       }
 286 +       if (attr == &gpiommc_attr_max_bus_speed) {
 287 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 288 +                                dev->pdata.max_bus_speed);
 289 +               goto out;
 290 +       }
 291 +       if (attr == &gpiommc_attr_register) {
 292 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 293 +                                gpiommc_is_registered(dev));
 294 +               goto out;
 295 +       }
 296 +       WARN_ON(1);
 297 +       err = -ENOSYS;
 298 +out:
 299 +       return err ? err : count;
 300 +}
 301 +
 302 +static int gpiommc_do_register(struct gpiommc_configfs_device *dev,
 303 +                              const char *name)
 304 +{
 305 +       int err;
 306 +
 307 +       if (gpiommc_is_registered(dev))
 308 +               return 0;
 309 +
 310 +       if (!gpio_is_valid(dev->pdata.pins.gpio_di) ||
 311 +           !gpio_is_valid(dev->pdata.pins.gpio_do) ||
 312 +           !gpio_is_valid(dev->pdata.pins.gpio_clk) ||
 313 +           !gpio_is_valid(dev->pdata.pins.gpio_cs)) {
 314 +               printk(KERN_ERR PFX
 315 +                      "configfs: Invalid GPIO pin number(s)\n");
 316 +               return -EINVAL;
 317 +       }
 318 +
 319 +       strlcpy(dev->pdata.name, name,
 320 +               sizeof(dev->pdata.name));
 321 +
 322 +       dev->pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME,
 323 +                                         gpiommc_next_id());
 324 +       if (!dev->pdev)
 325 +               return -ENOMEM;
 326 +       err = platform_device_add_data(dev->pdev, &dev->pdata,
 327 +                                      sizeof(dev->pdata));
 328 +       if (err) {
 329 +               platform_device_put(dev->pdev);
 330 +               return err;
 331 +       }
 332 +       err = platform_device_add(dev->pdev);
 333 +       if (err) {
 334 +               platform_device_put(dev->pdev);
 335 +               return err;
 336 +       }
 337 +
 338 +       return 0;
 339 +}
 340 +
 341 +static void gpiommc_do_unregister(struct gpiommc_configfs_device *dev)
 342 +{
 343 +       if (!gpiommc_is_registered(dev))
 344 +               return;
 345 +
 346 +       platform_device_unregister(dev->pdev);
 347 +       dev->pdev = NULL;
 348 +}
 349 +
 350 +static ssize_t gpiommc_config_attr_store(struct config_item *item,
 351 +                                        struct configfs_attribute *attr,
 352 +                                        const char *page, size_t count)
 353 +{
 354 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 355 +       int err = -EINVAL;
 356 +       unsigned long data;
 357 +
 358 +       if (attr == &gpiommc_attr_register) {
 359 +               err = strict_strtoul(page, 10, &data);
 360 +               if (err)
 361 +                       goto out;
 362 +               err = -EINVAL;
 363 +               if (data == 1)
 364 +                       err = gpiommc_do_register(dev, item->ci_name);
 365 +               if (data == 0) {
 366 +                       gpiommc_do_unregister(dev);
 367 +                       err = 0;
 368 +               }
 369 +               goto out;
 370 +       }
 371 +
 372 +       if (gpiommc_is_registered(dev)) {
 373 +               /* The rest of the config parameters can only be set
 374 +                * as long as the device is not registered, yet. */
 375 +               err = -EBUSY;
 376 +               goto out;
 377 +       }
 378 +
 379 +       if (attr == &gpiommc_attr_DI) {
 380 +               err = strict_strtoul(page, 10, &data);
 381 +               if (err)
 382 +                       goto out;
 383 +               err = -EINVAL;
 384 +               if (!gpio_is_valid(data))
 385 +                       goto out;
 386 +               dev->pdata.pins.gpio_di = data;
 387 +               err = 0;
 388 +               goto out;
 389 +       }
 390 +       if (attr == &gpiommc_attr_DO) {
 391 +               err = strict_strtoul(page, 10, &data);
 392 +               if (err)
 393 +                       goto out;
 394 +               err = -EINVAL;
 395 +               if (!gpio_is_valid(data))
 396 +                       goto out;
 397 +               dev->pdata.pins.gpio_do = data;
 398 +               err = 0;
 399 +               goto out;
 400 +       }
 401 +       if (attr == &gpiommc_attr_CLK) {
 402 +               err = strict_strtoul(page, 10, &data);
 403 +               if (err)
 404 +                       goto out;
 405 +               err = -EINVAL;
 406 +               if (!gpio_is_valid(data))
 407 +                       goto out;
 408 +               dev->pdata.pins.gpio_clk = data;
 409 +               err = 0;
 410 +               goto out;
 411 +       }
 412 +       if (attr == &gpiommc_attr_CS) {
 413 +               err = strict_strtoul(page, 10, &data);
 414 +               if (err)
 415 +                       goto out;
 416 +               err = -EINVAL;
 417 +               if (!gpio_is_valid(data))
 418 +                       goto out;
 419 +               dev->pdata.pins.gpio_cs = data;
 420 +               err = 0;
 421 +               goto out;
 422 +       }
 423 +       if (attr == &gpiommc_attr_CS_activelow) {
 424 +               err = strict_strtoul(page, 10, &data);
 425 +               if (err)
 426 +                       goto out;
 427 +               err = -EINVAL;
 428 +               if (data != 0 && data != 1)
 429 +                       goto out;
 430 +               dev->pdata.pins.cs_activelow = data;
 431 +               err = 0;
 432 +               goto out;
 433 +       }
 434 +       if (attr == &gpiommc_attr_spimode) {
 435 +               err = strict_strtoul(page, 10, &data);
 436 +               if (err)
 437 +                       goto out;
 438 +               err = -EINVAL;
 439 +               switch (data) {
 440 +               case 0:
 441 +                       dev->pdata.mode = SPI_MODE_0;
 442 +                       break;
 443 +               case 1:
 444 +                       dev->pdata.mode = SPI_MODE_1;
 445 +                       break;
 446 +               case 2:
 447 +                       dev->pdata.mode = SPI_MODE_2;
 448 +                       break;
 449 +               case 3:
 450 +                       dev->pdata.mode = SPI_MODE_3;
 451 +                       break;
 452 +               default:
 453 +                       goto out;
 454 +               }
 455 +               err = 0;
 456 +               goto out;
 457 +       }
 458 +       if (attr == &gpiommc_attr_spidelay) {
 459 +               err = strict_strtoul(page, 10, &data);
 460 +               if (err)
 461 +                       goto out;
 462 +               err = -EINVAL;
 463 +               if (data != 0 && data != 1)
 464 +                       goto out;
 465 +               dev->pdata.no_spi_delay = !data;
 466 +               err = 0;
 467 +               goto out;
 468 +       }
 469 +       if (attr == &gpiommc_attr_max_bus_speed) {
 470 +               err = strict_strtoul(page, 10, &data);
 471 +               if (err)
 472 +                       goto out;
 473 +               err = -EINVAL;
 474 +               if (data > UINT_MAX)
 475 +                       goto out;
 476 +               dev->pdata.max_bus_speed = data;
 477 +               err = 0;
 478 +               goto out;
 479 +       }
 480 +       WARN_ON(1);
 481 +       err = -ENOSYS;
 482 +out:
 483 +       return err ? err : count;
 484 +}
 485 +
 486 +static void gpiommc_config_item_release(struct config_item *item)
 487 +{
 488 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 489 +
 490 +       kfree(dev);
 491 +}
 492 +
 493 +static struct configfs_item_operations gpiommc_config_item_ops = {
 494 +       .release                = gpiommc_config_item_release,
 495 +       .show_attribute         = gpiommc_config_attr_show,
 496 +       .store_attribute        = gpiommc_config_attr_store,
 497 +};
 498 +
 499 +static struct config_item_type gpiommc_dev_ci_type = {
 500 +       .ct_item_ops    = &gpiommc_config_item_ops,
 501 +       .ct_attrs       = gpiommc_config_attrs,
 502 +       .ct_owner       = THIS_MODULE,
 503 +};
 504 +
 505 +static struct config_item *gpiommc_make_item(struct config_group *group,
 506 +                                            const char *name)
 507 +{
 508 +       struct gpiommc_configfs_device *dev;
 509 +
 510 +       if (strlen(name) > GPIOMMC_MAX_NAMELEN) {
 511 +               printk(KERN_ERR PFX "configfs: device name too long\n");
 512 +               return NULL;
 513 +       }
 514 +
 515 +       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 516 +       if (!dev)
 517 +               return NULL;
 518 +
 519 +       config_item_init_type_name(&dev->item, name,
 520 +                                  &gpiommc_dev_ci_type);
 521 +
 522 +       /* Assign default configuration */
 523 +       dev->pdata.pins.gpio_di = GPIO_INVALID;
 524 +       dev->pdata.pins.gpio_do = GPIO_INVALID;
 525 +       dev->pdata.pins.gpio_clk = GPIO_INVALID;
 526 +       dev->pdata.pins.gpio_cs = GPIO_INVALID;
 527 +       dev->pdata.pins.cs_activelow = 1;
 528 +       dev->pdata.mode = SPI_MODE_0;
 529 +       dev->pdata.no_spi_delay = 0;
 530 +       dev->pdata.max_bus_speed = 5000000; /* 5 MHz */
 531 +
 532 +       return &(dev->item);
 533 +}
 534 +
 535 +static void gpiommc_drop_item(struct config_group *group,
 536 +                             struct config_item *item)
 537 +{
 538 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 539 +
 540 +       gpiommc_do_unregister(dev);
 541 +       kfree(dev);
 542 +}
 543 +
 544 +static struct configfs_group_operations gpiommc_ct_group_ops = {
 545 +       .make_item      = gpiommc_make_item,
 546 +       .drop_item      = gpiommc_drop_item,
 547 +};
 548 +
 549 +static struct config_item_type gpiommc_ci_type = {
 550 +       .ct_group_ops   = &gpiommc_ct_group_ops,
 551 +       .ct_owner       = THIS_MODULE,
 552 +};
 553 +
 554 +static struct configfs_subsystem gpiommc_subsys = {
 555 +       .su_group = {
 556 +               .cg_item = {
 557 +                       .ci_namebuf = GPIOMMC_PLATDEV_NAME,
 558 +                       .ci_type = &gpiommc_ci_type,
 559 +               },
 560 +       },
 561 +       .su_mutex = __MUTEX_INITIALIZER(gpiommc_subsys.su_mutex),
 562 +};
 563 +
 564 +#endif /* CONFIG_GPIOMMC_CONFIGFS */
 565 +
 566 +static struct platform_driver gpiommc_plat_driver = {
 567 +       .probe  = gpiommc_probe,
 568 +       .remove = gpiommc_remove,
 569 +       .driver = {
 570 +               .name   = GPIOMMC_PLATDEV_NAME,
 571 +               .owner  = THIS_MODULE,
 572 +       },
 573 +};
 574 +
 575 +int gpiommc_next_id(void)
 576 +{
 577 +       static atomic_t counter = ATOMIC_INIT(-1);
 578 +
 579 +       return atomic_inc_return(&counter);
 580 +}
 581 +EXPORT_SYMBOL(gpiommc_next_id);
 582 +
 583 +static int __init gpiommc_modinit(void)
 584 +{
 585 +       int err;
 586 +
 587 +       err = platform_driver_register(&gpiommc_plat_driver);
 588 +       if (err)
 589 +               return err;
 590 +
 591 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 592 +       config_group_init(&gpiommc_subsys.su_group);
 593 +       err = configfs_register_subsystem(&gpiommc_subsys);
 594 +       if (err) {
 595 +               platform_driver_unregister(&gpiommc_plat_driver);
 596 +               return err;
 597 +       }
 598 +#endif /* CONFIG_GPIOMMC_CONFIGFS */
 599 +
 600 +       return 0;
 601 +}
 602 +module_init(gpiommc_modinit);
 603 +
 604 +static void __exit gpiommc_modexit(void)
 605 +{
 606 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 607 +       configfs_unregister_subsystem(&gpiommc_subsys);
 608 +#endif
 609 +       platform_driver_unregister(&gpiommc_plat_driver);
 610 +}
 611 +module_exit(gpiommc_modexit);
 612 --- a/drivers/mmc/host/Kconfig
 613 +++ b/drivers/mmc/host/Kconfig
 614 @@ -192,3 +192,28 @@ config MMC_TMIO
 615         help
 616           This provides support for the SD/MMC cell found in TC6393XB,
 617           T7L66XB and also ipaq ASIC3
 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 --- a/drivers/mmc/host/Makefile
 644 +++ b/drivers/mmc/host/Makefile
 645 @@ -22,4 +22,5 @@ obj-$(CONFIG_MMC_SPI)         += mmc_spi.o
 646  obj-$(CONFIG_MMC_S3C)          += s3cmci.o
 647  obj-$(CONFIG_MMC_SDRICOH_CS)   += sdricoh_cs.o
 648  obj-$(CONFIG_MMC_TMIO)         += tmio_mmc.o
 649 +obj-$(CONFIG_GPIOMMC)          += gpiommc.o
 650
 651 --- /dev/null
 652 +++ b/include/linux/mmc/gpiommc.h
 653 @@ -0,0 +1,71 @@
 654 +/*
 655 + * Device driver for MMC/SD cards driven over a GPIO bus.
 656 + *
 657 + * Copyright (c) 2008 Michael Buesch
 658 + *
 659 + * Licensed under the GNU/GPL version 2.
 660 + */
 661 +#ifndef LINUX_GPIOMMC_H_
 662 +#define LINUX_GPIOMMC_H_
 663 +
 664 +#include <linux/types.h>
 665 +
 666 +
 667 +#define GPIOMMC_MAX_NAMELEN            15
 668 +#define GPIOMMC_MAX_NAMELEN_STR                __stringify(GPIOMMC_MAX_NAMELEN)
 669 +
 670 +/**
 671 + * struct gpiommc_pins - Hardware pin assignments
 672 + *
 673 + * @gpio_di: The GPIO number of the DATA IN pin
 674 + * @gpio_do: The GPIO number of the DATA OUT pin
 675 + * @gpio_clk: The GPIO number of the CLOCK pin
 676 + * @gpio_cs: The GPIO number of the CHIPSELECT pin
 677 + * @cs_activelow: If true, the chip is considered selected if @gpio_cs is low.
 678 + */
 679 +struct gpiommc_pins {
 680 +       unsigned int gpio_di;
 681 +       unsigned int gpio_do;
 682 +       unsigned int gpio_clk;
 683 +       unsigned int gpio_cs;
 684 +       bool cs_activelow;
 685 +};
 686 +
 687 +/**
 688 + * struct gpiommc_platform_data - Platform data for a MMC-over-SPI-GPIO device.
 689 + *
 690 + * @name: The unique name string of the device.
 691 + * @pins: The hardware pin assignments.
 692 + * @mode: The hardware mode. This is either SPI_MODE_0,
 693 + *        SPI_MODE_1, SPI_MODE_2 or SPI_MODE_3. See the SPI documentation.
 694 + * @no_spi_delay: Do not use delays in the lowlevel SPI bitbanging code.
 695 + *                This is not standards compliant, but may be required for some
 696 + *                embedded machines to gain reasonable speed.
 697 + * @max_bus_speed: The maximum speed of the SPI bus, in Hertz.
 698 + */
 699 +struct gpiommc_platform_data {
 700 +       char name[GPIOMMC_MAX_NAMELEN + 1];
 701 +       struct gpiommc_pins pins;
 702 +       u8 mode;
 703 +       bool no_spi_delay;
 704 +       unsigned int max_bus_speed;
 705 +};
 706 +
 707 +/**
 708 + * GPIOMMC_PLATDEV_NAME - The platform device name string.
 709 + *
 710 + * The name string that has to be used for platform_device_alloc
 711 + * when allocating a gpiommc device.
 712 + */
 713 +#define GPIOMMC_PLATDEV_NAME   "gpiommc"
 714 +
 715 +/**
 716 + * gpiommc_next_id - Get another platform device ID number.
 717 + *
 718 + * This returns the next platform device ID number that has to be used
 719 + * for platform_device_alloc. The ID is opaque and should not be used for
 720 + * anything else.
 721 + */
 722 +int gpiommc_next_id(void);
 723 +
 724 +#endif /* LINUX_GPIOMMC_H_ */
 725 --- /dev/null
 726 +++ b/Documentation/gpiommc.txt
 727 @@ -0,0 +1,97 @@
 728 +GPIOMMC - Driver for an MMC/SD card on a bitbanging GPIO SPI bus
 729 +================================================================
 730 +
 731 +The gpiommc module hooks up the mmc_spi and spi_gpio modules for running an
 732 +MMC or SD card on GPIO pins.
 733 +
 734 +Two interfaces for registering a new MMC/SD card device are provided:
 735 +A static platform-device based mechanism and a dynamic configfs based interface.
 736 +
 737 +
 738 +Registering devices via platform-device
 739 +=======================================
 740 +
 741 +The platform-device interface is used for registering MMC/SD devices that are
 742 +part of the hardware platform. This is most useful only for embedded machines
 743 +with MMC/SD devices statically connected to the platform GPIO bus.
 744 +
 745 +The data structures are declared in <linux/mmc/gpiommc.h>.
 746 +
 747 +To register a new device, define an instance of struct gpiommc_platform_data.
 748 +This structure holds any information about how the device is hooked up to the
 749 +GPIO pins and what hardware modes the device supports. See the docbook-style
 750 +documentation in the header file for more information on the struct fields.
 751 +
 752 +Then allocate a new instance of a platform device by doing:
 753 +
 754 +       pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME, gpiommc_next_id());
 755 +
 756 +This will allocate the platform device data structures and hook it up to the
 757 +gpiommc driver.
 758 +Then add the gpiommc_platform_data to the platform device.
 759 +
 760 +       err = platform_device_add_data(pdev, pdata, sizeof(struct gpiommc_platform_data));
 761 +
 762 +You may free the local instance of struct gpiommc_platform_data now. (So the
 763 +struct may be allocated on the stack, too).
 764 +Now simply register the platform device.
 765 +
 766 +       err = platform_device_add(pdev);
 767 +
 768 +Done. The gpiommc probe routine will be invoked now and you should see a kernel
 769 +log message for the added device.
 770 +
 771 +
 772 +Registering devices via configfs
 773 +================================
 774 +
 775 +MMC/SD cards connected via GPIO often are a pretty dynamic thing, as for example
 776 +selfmade hacks for soldering an MMC/SD card to standard GPIO pins on embedded
 777 +hardware are a common situation.
 778 +So we provide a dynamic interface to conveniently handle adding and removing
 779 +devices from userspace, without the need to recompile the kernel.
 780 +
 781 +The "gpiommc" subdirectory at the configfs mountpoint is used for handling
 782 +the dynamic configuration.
 783 +
 784 +To create a new device, it must first be allocated with mkdir.
 785 +The following command will allocate a device named "my_mmc":
 786 +       mkdir /config/gpiommc/my_mmc
 787 +
 788 +There are several configuration files available in the new
 789 +/config/gpiommc/my_mmc/ directory:
 790 +
 791 +gpio_data_in                   = The SPI data-IN GPIO pin number.
 792 +gpio_data_out                  = The SPI data-OUT GPIO pin number.
 793 +gpio_clock                     = The SPI Clock GPIO pin number.
 794 +gpio_chipselect                        = The SPI Chipselect GPIO pin number.
 795 +gpio_chipselect_activelow      = Boolean. If 0, Chipselect is active-HIGH.
 796 +                                 If 1, Chipselect is active-LOW.
 797 +spi_mode                       = The SPI data mode. Can be 0-3.
 798 +spi_delay                      = Enable all delays in the lowlevel bitbanging.
 799 +max_bus_speed                  = The maximum SPI bus speed. In Hertz.
 800 +
 801 +register                       = Not a configuration parameter.
 802 +                                 Used to register the configured card
 803 +                                 with the kernel.
 804 +
 805 +The device must first get configured and then registered by writing "1" to
 806 +the "register" file.
 807 +The configuration parameters "gpio_data_in", "gpio_data_out", "gpio_clock"
 808 +and "gpio_chipselect" are essential and _must_ be configured before writing
 809 +"1" to the "register" file. The registration will fail, otherwise.
 810 +
 811 +The default values for the other parameters are:
 812 +gpio_chipselect_activelow      = 1             (CS active-LOW)
 813 +spi_mode                       = 0             (SPI_MODE_0)
 814 +spi_delay                      = 1             (enabled)
 815 +max_bus_speed                  = 5000000       (5 Mhz)
 816 +
 817 +Configuration values can not be changed after registration. To unregister
 818 +the device, write a "0" to the "register" file. The configuration can be
 819 +changed again after unregistering.
 820 +
 821 +To completely remove the device, simply rmdir the directory
 822 +(/config/gpiommc/my_mmc in this example).
 823 +There's no need to first unregister the device before removing it. That will
 824 +be done automatically.
 825 --- a/MAINTAINERS
 826 +++ b/MAINTAINERS
 827 @@ -1910,6 +1910,11 @@ W:       http://moinejf.free.fr
 828  L:     video4linux-list@redhat.com
 829  S:     Maintained
 830
 831 +GPIOMMC DRIVER
 832 +P:     Michael Buesch
 833 +M:     mb@bu3sch.de
 834 +S:     Maintained
 835 +
 836  HARDWARE MONITORING
 837  L:     lm-sensors@lm-sensors.org
 838  W:     http://www.lm-sensors.org/