target/linux/generic/patches-3.3/863-gpiommc.patch

   1 --- /dev/null
   2 +++ b/drivers/mmc/host/gpiommc.c
   3 @@ -0,0 +1,609 @@
   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/module.h>
  15 +#include <linux/mmc/gpiommc.h>
  16 +#include <linux/platform_device.h>
  17 +#include <linux/list.h>
  18 +#include <linux/mutex.h>
  19 +#include <linux/spi/spi_gpio_old.h>
  20 +#include <linux/configfs.h>
  21 +#include <linux/gpio.h>
  22 +#include <asm/atomic.h>
  23 +
  24 +
  25 +#define PFX                            "gpio-mmc: "
  26 +
  27 +
  28 +struct gpiommc_device {
  29 +       struct platform_device *pdev;
  30 +       struct platform_device *spi_pdev;
  31 +       struct spi_board_info boardinfo;
  32 +};
  33 +
  34 +
  35 +MODULE_DESCRIPTION("GPIO based MMC driver");
  36 +MODULE_AUTHOR("Michael Buesch");
  37 +MODULE_LICENSE("GPL");
  38 +
  39 +
  40 +static int gpiommc_boardinfo_setup(struct spi_board_info *bi,
  41 +                                  struct spi_master *master,
  42 +                                  void *data)
  43 +{
  44 +       struct gpiommc_device *d = data;
  45 +       struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
  46 +
  47 +       /* Bind the SPI master to the MMC-SPI host driver. */
  48 +       strlcpy(bi->modalias, "mmc_spi", sizeof(bi->modalias));
  49 +
  50 +       bi->max_speed_hz = pdata->max_bus_speed;
  51 +       bi->bus_num = master->bus_num;
  52 +       bi->mode = pdata->mode;
  53 +
  54 +       return 0;
  55 +}
  56 +
  57 +static int gpiommc_probe(struct platform_device *pdev)
  58 +{
  59 +       struct gpiommc_platform_data *mmc_pdata = pdev->dev.platform_data;
  60 +       struct spi_gpio_platform_data spi_pdata;
  61 +       struct gpiommc_device *d;
  62 +       int err;
  63 +
  64 +       err = -ENXIO;
  65 +       if (!mmc_pdata)
  66 +               goto error;
  67 +
  68 +#ifdef CONFIG_MMC_SPI_MODULE
  69 +       err = request_module("mmc_spi");
  70 +       if (err) {
  71 +               printk(KERN_WARNING PFX
  72 +                      "Failed to request mmc_spi module.\n");
  73 +       }
  74 +#endif /* CONFIG_MMC_SPI_MODULE */
  75 +
  76 +       /* Allocate the GPIO-MMC device */
  77 +       err = -ENOMEM;
  78 +       d = kzalloc(sizeof(*d), GFP_KERNEL);
  79 +       if (!d)
  80 +               goto error;
  81 +       d->pdev = pdev;
  82 +
  83 +       /* Create the SPI-GPIO device */
  84 +       d->spi_pdev = platform_device_alloc(SPI_GPIO_PLATDEV_NAME,
  85 +                                           spi_gpio_next_id());
  86 +       if (!d->spi_pdev)
  87 +               goto err_free_d;
  88 +
  89 +       memset(&spi_pdata, 0, sizeof(spi_pdata));
  90 +       spi_pdata.pin_clk = mmc_pdata->pins.gpio_clk;
  91 +       spi_pdata.pin_miso = mmc_pdata->pins.gpio_do;
  92 +       spi_pdata.pin_mosi = mmc_pdata->pins.gpio_di;
  93 +       spi_pdata.pin_cs = mmc_pdata->pins.gpio_cs;
  94 +       spi_pdata.cs_activelow = mmc_pdata->pins.cs_activelow;
  95 +       spi_pdata.no_spi_delay = mmc_pdata->no_spi_delay;
  96 +       spi_pdata.boardinfo_setup = gpiommc_boardinfo_setup;
  97 +       spi_pdata.boardinfo_setup_data = d;
  98 +
  99 +       err = platform_device_add_data(d->spi_pdev, &spi_pdata,
 100 +                                      sizeof(spi_pdata));
 101 +       if (err)
 102 +               goto err_free_pdev;
 103 +       err = platform_device_add(d->spi_pdev);
 104 +       if (err)
 105 +               goto err_free_pdata;
 106 +       platform_set_drvdata(pdev, d);
 107 +
 108 +       printk(KERN_INFO PFX "MMC-Card \"%s\" "
 109 +              "attached to GPIO pins di=%u, do=%u, clk=%u, cs=%u\n",
 110 +              mmc_pdata->name, mmc_pdata->pins.gpio_di,
 111 +              mmc_pdata->pins.gpio_do,
 112 +              mmc_pdata->pins.gpio_clk,
 113 +              mmc_pdata->pins.gpio_cs);
 114 +
 115 +       return 0;
 116 +
 117 +err_free_pdata:
 118 +       kfree(d->spi_pdev->dev.platform_data);
 119 +       d->spi_pdev->dev.platform_data = NULL;
 120 +err_free_pdev:
 121 +       platform_device_put(d->spi_pdev);
 122 +err_free_d:
 123 +       kfree(d);
 124 +error:
 125 +       return err;
 126 +}
 127 +
 128 +static int gpiommc_remove(struct platform_device *pdev)
 129 +{
 130 +       struct gpiommc_device *d = platform_get_drvdata(pdev);
 131 +       struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
 132 +
 133 +       platform_device_unregister(d->spi_pdev);
 134 +       printk(KERN_INFO PFX "GPIO based MMC-Card \"%s\" removed\n",
 135 +              pdata->name);
 136 +       platform_device_put(d->spi_pdev);
 137 +
 138 +       return 0;
 139 +}
 140 +
 141 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 142 +
 143 +/* A device that was created through configfs */
 144 +struct gpiommc_configfs_device {
 145 +       struct config_item item;
 146 +       /* The platform device, after registration. */
 147 +       struct platform_device *pdev;
 148 +       /* The configuration */
 149 +       struct gpiommc_platform_data pdata;
 150 +};
 151 +
 152 +#define GPIO_INVALID   -1
 153 +
 154 +static inline bool gpiommc_is_registered(struct gpiommc_configfs_device *dev)
 155 +{
 156 +       return (dev->pdev != NULL);
 157 +}
 158 +
 159 +static inline struct gpiommc_configfs_device *ci_to_gpiommc(struct config_item *item)
 160 +{
 161 +       return item ? container_of(item, struct gpiommc_configfs_device, item) : NULL;
 162 +}
 163 +
 164 +static struct configfs_attribute gpiommc_attr_DI = {
 165 +       .ca_owner = THIS_MODULE,
 166 +       .ca_name = "gpio_data_in",
 167 +       .ca_mode = S_IRUGO | S_IWUSR,
 168 +};
 169 +
 170 +static struct configfs_attribute gpiommc_attr_DO = {
 171 +       .ca_owner = THIS_MODULE,
 172 +       .ca_name = "gpio_data_out",
 173 +       .ca_mode = S_IRUGO | S_IWUSR,
 174 +};
 175 +
 176 +static struct configfs_attribute gpiommc_attr_CLK = {
 177 +       .ca_owner = THIS_MODULE,
 178 +       .ca_name = "gpio_clock",
 179 +       .ca_mode = S_IRUGO | S_IWUSR,
 180 +};
 181 +
 182 +static struct configfs_attribute gpiommc_attr_CS = {
 183 +       .ca_owner = THIS_MODULE,
 184 +       .ca_name = "gpio_chipselect",
 185 +       .ca_mode = S_IRUGO | S_IWUSR,
 186 +};
 187 +
 188 +static struct configfs_attribute gpiommc_attr_CS_activelow = {
 189 +       .ca_owner = THIS_MODULE,
 190 +       .ca_name = "gpio_chipselect_activelow",
 191 +       .ca_mode = S_IRUGO | S_IWUSR,
 192 +};
 193 +
 194 +static struct configfs_attribute gpiommc_attr_spimode = {
 195 +       .ca_owner = THIS_MODULE,
 196 +       .ca_name = "spi_mode",
 197 +       .ca_mode = S_IRUGO | S_IWUSR,
 198 +};
 199 +
 200 +static struct configfs_attribute gpiommc_attr_spidelay = {
 201 +       .ca_owner = THIS_MODULE,
 202 +       .ca_name = "spi_delay",
 203 +       .ca_mode = S_IRUGO | S_IWUSR,
 204 +};
 205 +
 206 +static struct configfs_attribute gpiommc_attr_max_bus_speed = {
 207 +       .ca_owner = THIS_MODULE,
 208 +       .ca_name = "max_bus_speed",
 209 +       .ca_mode = S_IRUGO | S_IWUSR,
 210 +};
 211 +
 212 +static struct configfs_attribute gpiommc_attr_register = {
 213 +       .ca_owner = THIS_MODULE,
 214 +       .ca_name = "register",
 215 +       .ca_mode = S_IRUGO | S_IWUSR,
 216 +};
 217 +
 218 +static struct configfs_attribute *gpiommc_config_attrs[] = {
 219 +       &gpiommc_attr_DI,
 220 +       &gpiommc_attr_DO,
 221 +       &gpiommc_attr_CLK,
 222 +       &gpiommc_attr_CS,
 223 +       &gpiommc_attr_CS_activelow,
 224 +       &gpiommc_attr_spimode,
 225 +       &gpiommc_attr_spidelay,
 226 +       &gpiommc_attr_max_bus_speed,
 227 +       &gpiommc_attr_register,
 228 +       NULL,
 229 +};
 230 +
 231 +static ssize_t gpiommc_config_attr_show(struct config_item *item,
 232 +                                       struct configfs_attribute *attr,
 233 +                                       char *page)
 234 +{
 235 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 236 +       ssize_t count = 0;
 237 +       unsigned int gpio;
 238 +       int err = 0;
 239 +
 240 +       if (attr == &gpiommc_attr_DI) {
 241 +               gpio = dev->pdata.pins.gpio_di;
 242 +               if (gpio == GPIO_INVALID)
 243 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 244 +               else
 245 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 246 +               goto out;
 247 +       }
 248 +       if (attr == &gpiommc_attr_DO) {
 249 +               gpio = dev->pdata.pins.gpio_do;
 250 +               if (gpio == GPIO_INVALID)
 251 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 252 +               else
 253 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 254 +               goto out;
 255 +       }
 256 +       if (attr == &gpiommc_attr_CLK) {
 257 +               gpio = dev->pdata.pins.gpio_clk;
 258 +               if (gpio == GPIO_INVALID)
 259 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 260 +               else
 261 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 262 +               goto out;
 263 +       }
 264 +       if (attr == &gpiommc_attr_CS) {
 265 +               gpio = dev->pdata.pins.gpio_cs;
 266 +               if (gpio == GPIO_INVALID)
 267 +                       count = snprintf(page, PAGE_SIZE, "not configured\n");
 268 +               else
 269 +                       count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
 270 +               goto out;
 271 +       }
 272 +       if (attr == &gpiommc_attr_CS_activelow) {
 273 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 274 +                                dev->pdata.pins.cs_activelow);
 275 +               goto out;
 276 +       }
 277 +       if (attr == &gpiommc_attr_spimode) {
 278 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 279 +                                dev->pdata.mode);
 280 +               goto out;
 281 +       }
 282 +       if (attr == &gpiommc_attr_spidelay) {
 283 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 284 +                                !dev->pdata.no_spi_delay);
 285 +               goto out;
 286 +       }
 287 +       if (attr == &gpiommc_attr_max_bus_speed) {
 288 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 289 +                                dev->pdata.max_bus_speed);
 290 +               goto out;
 291 +       }
 292 +       if (attr == &gpiommc_attr_register) {
 293 +               count = snprintf(page, PAGE_SIZE, "%u\n",
 294 +                                gpiommc_is_registered(dev));
 295 +               goto out;
 296 +       }
 297 +       WARN_ON(1);
 298 +       err = -ENOSYS;
 299 +out:
 300 +       return err ? err : count;
 301 +}
 302 +
 303 +static int gpiommc_do_register(struct gpiommc_configfs_device *dev,
 304 +                              const char *name)
 305 +{
 306 +       int err;
 307 +
 308 +       if (gpiommc_is_registered(dev))
 309 +               return 0;
 310 +
 311 +       if (!gpio_is_valid(dev->pdata.pins.gpio_di) ||
 312 +           !gpio_is_valid(dev->pdata.pins.gpio_do) ||
 313 +           !gpio_is_valid(dev->pdata.pins.gpio_clk) ||
 314 +           !gpio_is_valid(dev->pdata.pins.gpio_cs)) {
 315 +               printk(KERN_ERR PFX
 316 +                      "configfs: Invalid GPIO pin number(s)\n");
 317 +               return -EINVAL;
 318 +       }
 319 +
 320 +       strlcpy(dev->pdata.name, name,
 321 +               sizeof(dev->pdata.name));
 322 +
 323 +       dev->pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME,
 324 +                                         gpiommc_next_id());
 325 +       if (!dev->pdev)
 326 +               return -ENOMEM;
 327 +       err = platform_device_add_data(dev->pdev, &dev->pdata,
 328 +                                      sizeof(dev->pdata));
 329 +       if (err) {
 330 +               platform_device_put(dev->pdev);
 331 +               return err;
 332 +       }
 333 +       err = platform_device_add(dev->pdev);
 334 +       if (err) {
 335 +               platform_device_put(dev->pdev);
 336 +               return err;
 337 +       }
 338 +
 339 +       return 0;
 340 +}
 341 +
 342 +static void gpiommc_do_unregister(struct gpiommc_configfs_device *dev)
 343 +{
 344 +       if (!gpiommc_is_registered(dev))
 345 +               return;
 346 +
 347 +       platform_device_unregister(dev->pdev);
 348 +       dev->pdev = NULL;
 349 +}
 350 +
 351 +static ssize_t gpiommc_config_attr_store(struct config_item *item,
 352 +                                        struct configfs_attribute *attr,
 353 +                                        const char *page, size_t count)
 354 +{
 355 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 356 +       int err = -EINVAL;
 357 +       unsigned long data;
 358 +
 359 +       if (attr == &gpiommc_attr_register) {
 360 +               err = strict_strtoul(page, 10, &data);
 361 +               if (err)
 362 +                       goto out;
 363 +               err = -EINVAL;
 364 +               if (data == 1)
 365 +                       err = gpiommc_do_register(dev, item->ci_name);
 366 +               if (data == 0) {
 367 +                       gpiommc_do_unregister(dev);
 368 +                       err = 0;
 369 +               }
 370 +               goto out;
 371 +       }
 372 +
 373 +       if (gpiommc_is_registered(dev)) {
 374 +               /* The rest of the config parameters can only be set
 375 +                * as long as the device is not registered, yet. */
 376 +               err = -EBUSY;
 377 +               goto out;
 378 +       }
 379 +
 380 +       if (attr == &gpiommc_attr_DI) {
 381 +               err = strict_strtoul(page, 10, &data);
 382 +               if (err)
 383 +                       goto out;
 384 +               err = -EINVAL;
 385 +               if (!gpio_is_valid(data))
 386 +                       goto out;
 387 +               dev->pdata.pins.gpio_di = data;
 388 +               err = 0;
 389 +               goto out;
 390 +       }
 391 +       if (attr == &gpiommc_attr_DO) {
 392 +               err = strict_strtoul(page, 10, &data);
 393 +               if (err)
 394 +                       goto out;
 395 +               err = -EINVAL;
 396 +               if (!gpio_is_valid(data))
 397 +                       goto out;
 398 +               dev->pdata.pins.gpio_do = data;
 399 +               err = 0;
 400 +               goto out;
 401 +       }
 402 +       if (attr == &gpiommc_attr_CLK) {
 403 +               err = strict_strtoul(page, 10, &data);
 404 +               if (err)
 405 +                       goto out;
 406 +               err = -EINVAL;
 407 +               if (!gpio_is_valid(data))
 408 +                       goto out;
 409 +               dev->pdata.pins.gpio_clk = data;
 410 +               err = 0;
 411 +               goto out;
 412 +       }
 413 +       if (attr == &gpiommc_attr_CS) {
 414 +               err = strict_strtoul(page, 10, &data);
 415 +               if (err)
 416 +                       goto out;
 417 +               err = -EINVAL;
 418 +               if (!gpio_is_valid(data))
 419 +                       goto out;
 420 +               dev->pdata.pins.gpio_cs = data;
 421 +               err = 0;
 422 +               goto out;
 423 +       }
 424 +       if (attr == &gpiommc_attr_CS_activelow) {
 425 +               err = strict_strtoul(page, 10, &data);
 426 +               if (err)
 427 +                       goto out;
 428 +               err = -EINVAL;
 429 +               if (data != 0 && data != 1)
 430 +                       goto out;
 431 +               dev->pdata.pins.cs_activelow = data;
 432 +               err = 0;
 433 +               goto out;
 434 +       }
 435 +       if (attr == &gpiommc_attr_spimode) {
 436 +               err = strict_strtoul(page, 10, &data);
 437 +               if (err)
 438 +                       goto out;
 439 +               err = -EINVAL;
 440 +               switch (data) {
 441 +               case 0:
 442 +                       dev->pdata.mode = SPI_MODE_0;
 443 +                       break;
 444 +               case 1:
 445 +                       dev->pdata.mode = SPI_MODE_1;
 446 +                       break;
 447 +               case 2:
 448 +                       dev->pdata.mode = SPI_MODE_2;
 449 +                       break;
 450 +               case 3:
 451 +                       dev->pdata.mode = SPI_MODE_3;
 452 +                       break;
 453 +               default:
 454 +                       goto out;
 455 +               }
 456 +               err = 0;
 457 +               goto out;
 458 +       }
 459 +       if (attr == &gpiommc_attr_spidelay) {
 460 +               err = strict_strtoul(page, 10, &data);
 461 +               if (err)
 462 +                       goto out;
 463 +               err = -EINVAL;
 464 +               if (data != 0 && data != 1)
 465 +                       goto out;
 466 +               dev->pdata.no_spi_delay = !data;
 467 +               err = 0;
 468 +               goto out;
 469 +       }
 470 +       if (attr == &gpiommc_attr_max_bus_speed) {
 471 +               err = strict_strtoul(page, 10, &data);
 472 +               if (err)
 473 +                       goto out;
 474 +               err = -EINVAL;
 475 +               if (data > UINT_MAX)
 476 +                       goto out;
 477 +               dev->pdata.max_bus_speed = data;
 478 +               err = 0;
 479 +               goto out;
 480 +       }
 481 +       WARN_ON(1);
 482 +       err = -ENOSYS;
 483 +out:
 484 +       return err ? err : count;
 485 +}
 486 +
 487 +static void gpiommc_config_item_release(struct config_item *item)
 488 +{
 489 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 490 +
 491 +       kfree(dev);
 492 +}
 493 +
 494 +static struct configfs_item_operations gpiommc_config_item_ops = {
 495 +       .release                = gpiommc_config_item_release,
 496 +       .show_attribute         = gpiommc_config_attr_show,
 497 +       .store_attribute        = gpiommc_config_attr_store,
 498 +};
 499 +
 500 +static struct config_item_type gpiommc_dev_ci_type = {
 501 +       .ct_item_ops    = &gpiommc_config_item_ops,
 502 +       .ct_attrs       = gpiommc_config_attrs,
 503 +       .ct_owner       = THIS_MODULE,
 504 +};
 505 +
 506 +static struct config_item *gpiommc_make_item(struct config_group *group,
 507 +                                            const char *name)
 508 +{
 509 +       struct gpiommc_configfs_device *dev;
 510 +
 511 +       if (strlen(name) > GPIOMMC_MAX_NAMELEN) {
 512 +               printk(KERN_ERR PFX "configfs: device name too long\n");
 513 +               return NULL;
 514 +       }
 515 +
 516 +       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 517 +       if (!dev)
 518 +               return NULL;
 519 +
 520 +       config_item_init_type_name(&dev->item, name,
 521 +                                  &gpiommc_dev_ci_type);
 522 +
 523 +       /* Assign default configuration */
 524 +       dev->pdata.pins.gpio_di = GPIO_INVALID;
 525 +       dev->pdata.pins.gpio_do = GPIO_INVALID;
 526 +       dev->pdata.pins.gpio_clk = GPIO_INVALID;
 527 +       dev->pdata.pins.gpio_cs = GPIO_INVALID;
 528 +       dev->pdata.pins.cs_activelow = 1;
 529 +       dev->pdata.mode = SPI_MODE_0;
 530 +       dev->pdata.no_spi_delay = 0;
 531 +       dev->pdata.max_bus_speed = 5000000; /* 5 MHz */
 532 +
 533 +       return &(dev->item);
 534 +}
 535 +
 536 +static void gpiommc_drop_item(struct config_group *group,
 537 +                             struct config_item *item)
 538 +{
 539 +       struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
 540 +
 541 +       gpiommc_do_unregister(dev);
 542 +       kfree(dev);
 543 +}
 544 +
 545 +static struct configfs_group_operations gpiommc_ct_group_ops = {
 546 +       .make_item      = gpiommc_make_item,
 547 +       .drop_item      = gpiommc_drop_item,
 548 +};
 549 +
 550 +static struct config_item_type gpiommc_ci_type = {
 551 +       .ct_group_ops   = &gpiommc_ct_group_ops,
 552 +       .ct_owner       = THIS_MODULE,
 553 +};
 554 +
 555 +static struct configfs_subsystem gpiommc_subsys = {
 556 +       .su_group = {
 557 +               .cg_item = {
 558 +                       .ci_namebuf = GPIOMMC_PLATDEV_NAME,
 559 +                       .ci_type = &gpiommc_ci_type,
 560 +               },
 561 +       },
 562 +       .su_mutex = __MUTEX_INITIALIZER(gpiommc_subsys.su_mutex),
 563 +};
 564 +
 565 +#endif /* CONFIG_GPIOMMC_CONFIGFS */
 566 +
 567 +static struct platform_driver gpiommc_plat_driver = {
 568 +       .probe  = gpiommc_probe,
 569 +       .remove = gpiommc_remove,
 570 +       .driver = {
 571 +               .name   = GPIOMMC_PLATDEV_NAME,
 572 +               .owner  = THIS_MODULE,
 573 +       },
 574 +};
 575 +
 576 +int gpiommc_next_id(void)
 577 +{
 578 +       static atomic_t counter = ATOMIC_INIT(-1);
 579 +
 580 +       return atomic_inc_return(&counter);
 581 +}
 582 +EXPORT_SYMBOL(gpiommc_next_id);
 583 +
 584 +static int __init gpiommc_modinit(void)
 585 +{
 586 +       int err;
 587 +
 588 +       err = platform_driver_register(&gpiommc_plat_driver);
 589 +       if (err)
 590 +               return err;
 591 +
 592 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 593 +       config_group_init(&gpiommc_subsys.su_group);
 594 +       err = configfs_register_subsystem(&gpiommc_subsys);
 595 +       if (err) {
 596 +               platform_driver_unregister(&gpiommc_plat_driver);
 597 +               return err;
 598 +       }
 599 +#endif /* CONFIG_GPIOMMC_CONFIGFS */
 600 +
 601 +       return 0;
 602 +}
 603 +module_init(gpiommc_modinit);
 604 +
 605 +static void __exit gpiommc_modexit(void)
 606 +{
 607 +#ifdef CONFIG_GPIOMMC_CONFIGFS
 608 +       configfs_unregister_subsystem(&gpiommc_subsys);
 609 +#endif
 610 +       platform_driver_unregister(&gpiommc_plat_driver);
 611 +}
 612 +module_exit(gpiommc_modexit);
 613 --- a/drivers/mmc/host/Kconfig
 614 +++ b/drivers/mmc/host/Kconfig
 615 @@ -474,6 +474,31 @@ config MMC_SDHI
 616           This provides support for the SDHI SD/SDIO controller found in
 617           SuperH and ARM SH-Mobile SoCs
 618
 619 +config GPIOMMC
 620 +       tristate "MMC/SD over GPIO-based SPI"
 621 +       depends on MMC && MMC_SPI && SPI_GPIO_OLD
 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 +
 644  config MMC_CB710
 645         tristate "ENE CB710 MMC/SD Interface support"
 646         depends on PCI
 647 --- a/drivers/mmc/host/Makefile
 648 +++ b/drivers/mmc/host/Makefile
 649 @@ -37,6 +37,7 @@ tmio_mmc_core-$(subst m,y,$(CONFIG_MMC_S
 650  obj-$(CONFIG_MMC_SDHI)         += sh_mobile_sdhi.o
 651  obj-$(CONFIG_MMC_CB710)                += cb710-mmc.o
 652  obj-$(CONFIG_MMC_VIA_SDMMC)    += via-sdmmc.o
 653 +obj-$(CONFIG_GPIOMMC)          += gpiommc.o
 654  obj-$(CONFIG_SDH_BFIN)         += bfin_sdh.o
 655  obj-$(CONFIG_MMC_DW)           += dw_mmc.o
 656  obj-$(CONFIG_MMC_SH_MMCIF)     += sh_mmcif.o
 657 --- /dev/null
 658 +++ b/include/linux/mmc/gpiommc.h
 659 @@ -0,0 +1,71 @@
 660 +/*
 661 + * Device driver for MMC/SD cards driven over a GPIO bus.
 662 + *
 663 + * Copyright (c) 2008 Michael Buesch
 664 + *
 665 + * Licensed under the GNU/GPL version 2.
 666 + */
 667 +#ifndef LINUX_GPIOMMC_H_
 668 +#define LINUX_GPIOMMC_H_
 669 +
 670 +#include <linux/types.h>
 671 +
 672 +
 673 +#define GPIOMMC_MAX_NAMELEN            15
 674 +#define GPIOMMC_MAX_NAMELEN_STR                __stringify(GPIOMMC_MAX_NAMELEN)
 675 +
 676 +/**
 677 + * struct gpiommc_pins - Hardware pin assignments
 678 + *
 679 + * @gpio_di: The GPIO number of the DATA IN pin
 680 + * @gpio_do: The GPIO number of the DATA OUT pin
 681 + * @gpio_clk: The GPIO number of the CLOCK pin
 682 + * @gpio_cs: The GPIO number of the CHIPSELECT pin
 683 + * @cs_activelow: If true, the chip is considered selected if @gpio_cs is low.
 684 + */
 685 +struct gpiommc_pins {
 686 +       unsigned int gpio_di;
 687 +       unsigned int gpio_do;
 688 +       unsigned int gpio_clk;
 689 +       unsigned int gpio_cs;
 690 +       bool cs_activelow;
 691 +};
 692 +
 693 +/**
 694 + * struct gpiommc_platform_data - Platform data for a MMC-over-SPI-GPIO device.
 695 + *
 696 + * @name: The unique name string of the device.
 697 + * @pins: The hardware pin assignments.
 698 + * @mode: The hardware mode. This is either SPI_MODE_0,
 699 + *        SPI_MODE_1, SPI_MODE_2 or SPI_MODE_3. See the SPI documentation.
 700 + * @no_spi_delay: Do not use delays in the lowlevel SPI bitbanging code.
 701 + *                This is not standards compliant, but may be required for some
 702 + *                embedded machines to gain reasonable speed.
 703 + * @max_bus_speed: The maximum speed of the SPI bus, in Hertz.
 704 + */
 705 +struct gpiommc_platform_data {
 706 +       char name[GPIOMMC_MAX_NAMELEN + 1];
 707 +       struct gpiommc_pins pins;
 708 +       u8 mode;
 709 +       bool no_spi_delay;
 710 +       unsigned int max_bus_speed;
 711 +};
 712 +
 713 +/**
 714 + * GPIOMMC_PLATDEV_NAME - The platform device name string.
 715 + *
 716 + * The name string that has to be used for platform_device_alloc
 717 + * when allocating a gpiommc device.
 718 + */
 719 +#define GPIOMMC_PLATDEV_NAME   "gpiommc"
 720 +
 721 +/**
 722 + * gpiommc_next_id - Get another platform device ID number.
 723 + *
 724 + * This returns the next platform device ID number that has to be used
 725 + * for platform_device_alloc. The ID is opaque and should not be used for
 726 + * anything else.
 727 + */
 728 +int gpiommc_next_id(void);
 729 +
 730 +#endif /* LINUX_GPIOMMC_H_ */
 731 --- /dev/null
 732 +++ b/Documentation/gpiommc.txt
 733 @@ -0,0 +1,97 @@
 734 +GPIOMMC - Driver for an MMC/SD card on a bitbanging GPIO SPI bus
 735 +================================================================
 736 +
 737 +The gpiommc module hooks up the mmc_spi and spi_gpio modules for running an
 738 +MMC or SD card on GPIO pins.
 739 +
 740 +Two interfaces for registering a new MMC/SD card device are provided:
 741 +A static platform-device based mechanism and a dynamic configfs based interface.
 742 +
 743 +
 744 +Registering devices via platform-device
 745 +=======================================
 746 +
 747 +The platform-device interface is used for registering MMC/SD devices that are
 748 +part of the hardware platform. This is most useful only for embedded machines
 749 +with MMC/SD devices statically connected to the platform GPIO bus.
 750 +
 751 +The data structures are declared in <linux/mmc/gpiommc.h>.
 752 +
 753 +To register a new device, define an instance of struct gpiommc_platform_data.
 754 +This structure holds any information about how the device is hooked up to the
 755 +GPIO pins and what hardware modes the device supports. See the docbook-style
 756 +documentation in the header file for more information on the struct fields.
 757 +
 758 +Then allocate a new instance of a platform device by doing:
 759 +
 760 +       pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME, gpiommc_next_id());
 761 +
 762 +This will allocate the platform device data structures and hook it up to the
 763 +gpiommc driver.
 764 +Then add the gpiommc_platform_data to the platform device.
 765 +
 766 +       err = platform_device_add_data(pdev, pdata, sizeof(struct gpiommc_platform_data));
 767 +
 768 +You may free the local instance of struct gpiommc_platform_data now. (So the
 769 +struct may be allocated on the stack, too).
 770 +Now simply register the platform device.
 771 +
 772 +       err = platform_device_add(pdev);
 773 +
 774 +Done. The gpiommc probe routine will be invoked now and you should see a kernel
 775 +log message for the added device.
 776 +
 777 +
 778 +Registering devices via configfs
 779 +================================
 780 +
 781 +MMC/SD cards connected via GPIO often are a pretty dynamic thing, as for example
 782 +selfmade hacks for soldering an MMC/SD card to standard GPIO pins on embedded
 783 +hardware are a common situation.
 784 +So we provide a dynamic interface to conveniently handle adding and removing
 785 +devices from userspace, without the need to recompile the kernel.
 786 +
 787 +The "gpiommc" subdirectory at the configfs mountpoint is used for handling
 788 +the dynamic configuration.
 789 +
 790 +To create a new device, it must first be allocated with mkdir.
 791 +The following command will allocate a device named "my_mmc":
 792 +       mkdir /config/gpiommc/my_mmc
 793 +
 794 +There are several configuration files available in the new
 795 +/config/gpiommc/my_mmc/ directory:
 796 +
 797 +gpio_data_in                   = The SPI data-IN GPIO pin number.
 798 +gpio_data_out                  = The SPI data-OUT GPIO pin number.
 799 +gpio_clock                     = The SPI Clock GPIO pin number.
 800 +gpio_chipselect                        = The SPI Chipselect GPIO pin number.
 801 +gpio_chipselect_activelow      = Boolean. If 0, Chipselect is active-HIGH.
 802 +                                 If 1, Chipselect is active-LOW.
 803 +spi_mode                       = The SPI data mode. Can be 0-3.
 804 +spi_delay                      = Enable all delays in the lowlevel bitbanging.
 805 +max_bus_speed                  = The maximum SPI bus speed. In Hertz.
 806 +
 807 +register                       = Not a configuration parameter.
 808 +                                 Used to register the configured card
 809 +                                 with the kernel.
 810 +
 811 +The device must first get configured and then registered by writing "1" to
 812 +the "register" file.
 813 +The configuration parameters "gpio_data_in", "gpio_data_out", "gpio_clock"
 814 +and "gpio_chipselect" are essential and _must_ be configured before writing
 815 +"1" to the "register" file. The registration will fail, otherwise.
 816 +
 817 +The default values for the other parameters are:
 818 +gpio_chipselect_activelow      = 1             (CS active-LOW)
 819 +spi_mode                       = 0             (SPI_MODE_0)
 820 +spi_delay                      = 1             (enabled)
 821 +max_bus_speed                  = 5000000       (5 Mhz)
 822 +
 823 +Configuration values can not be changed after registration. To unregister
 824 +the device, write a "0" to the "register" file. The configuration can be
 825 +changed again after unregistering.
 826 +
 827 +To completely remove the device, simply rmdir the directory
 828 +(/config/gpiommc/my_mmc in this example).
 829 +There's no need to first unregister the device before removing it. That will
 830 +be done automatically.
 831 --- a/MAINTAINERS
 832 +++ b/MAINTAINERS
 833 @@ -3019,6 +3019,11 @@ L:       linuxppc-dev@lists.ozlabs.org
 834  S:     Odd Fixes
 835  F:     drivers/tty/hvc/
 836
 837 +GPIOMMC DRIVER
 838 +P:     Michael Buesch
 839 +M:     mb@bu3sch.de
 840 +S:     Maintained
 841 +
 842  HARDWARE MONITORING
 843  M:     Jean Delvare <khali@linux-fr.org>
 844  M:     Guenter Roeck <guenter.roeck@ericsson.com>