drivers/mmc/core/slot-gpio.c

   1 /*
   2  * Generic GPIO card-detect helper
   3  *
   4  * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/err.h>
  12 #include <linux/gpio.h>
  13 #include <linux/gpio/consumer.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/mmc/host.h>
  17 #include <linux/mmc/slot-gpio.h>
  18 #include <linux/module.h>
  19 #include <linux/slab.h>
  20
  21 struct mmc_gpio {
  22         struct gpio_desc *ro_gpio;
  23         struct gpio_desc *cd_gpio;
  24         bool override_ro_active_level;
  25         bool override_cd_active_level;
  26         char *ro_label;
  27         char cd_label[0];
  28 };
  29
  30 static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
  31 {
  32         /* Schedule a card detection after a debounce timeout */
  33         struct mmc_host *host = dev_id;
  34
  35         host->trigger_card_event = true;
  36         mmc_detect_change(host, msecs_to_jiffies(200));
  37
  38         return IRQ_HANDLED;
  39 }
  40
  41 static int mmc_gpio_alloc(struct mmc_host *host)
  42 {
  43         size_t len = strlen(dev_name(host->parent)) + 4;
  44         struct mmc_gpio *ctx;
  45
  46         mutex_lock(&host->slot.lock);
  47
  48         ctx = host->slot.handler_priv;
  49         if (!ctx) {
  50                 /*
  51                  * devm_kzalloc() can be called after device_initialize(), even
  52                  * before device_add(), i.e., between mmc_alloc_host() and
  53                  * mmc_add_host()
  54                  */
  55                 ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len,
  56                                    GFP_KERNEL);
  57                 if (ctx) {
  58                         ctx->ro_label = ctx->cd_label + len;
  59                         snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
  60                         snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent));
  61                         host->slot.handler_priv = ctx;
  62                 }
  63         }
  64
  65         mutex_unlock(&host->slot.lock);
  66
  67         return ctx ? 0 : -ENOMEM;
  68 }
  69
  70 int mmc_gpio_get_ro(struct mmc_host *host)
  71 {
  72         struct mmc_gpio *ctx = host->slot.handler_priv;
  73
  74         if (!ctx || !ctx->ro_gpio)
  75                 return -ENOSYS;
  76
  77         if (ctx->override_ro_active_level)
  78                 return !gpiod_get_raw_value_cansleep(ctx->ro_gpio) ^
  79                         !!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH);
  80
  81         return gpiod_get_value_cansleep(ctx->ro_gpio);
  82 }
  83 EXPORT_SYMBOL(mmc_gpio_get_ro);
  84
  85 int mmc_gpio_get_cd(struct mmc_host *host)
  86 {
  87         struct mmc_gpio *ctx = host->slot.handler_priv;
  88
  89         if (!ctx || !ctx->cd_gpio)
  90                 return -ENOSYS;
  91
  92         if (ctx->override_cd_active_level)
  93                 return !gpiod_get_raw_value_cansleep(ctx->cd_gpio) ^
  94                         !!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
  95
  96         return gpiod_get_value_cansleep(ctx->cd_gpio);
  97 }
  98 EXPORT_SYMBOL(mmc_gpio_get_cd);
  99
 100 /**
 101  * mmc_gpio_request_ro - request a gpio for write-protection
 102  * @host: mmc host
 103  * @gpio: gpio number requested
 104  *
 105  * As devm_* managed functions are used in mmc_gpio_request_ro(), client
 106  * drivers do not need to explicitly call mmc_gpio_free_ro() for freeing up,
 107  * if the requesting and freeing are only needed at probing and unbinding time
 108  * for once.  However, if client drivers do something special like runtime
 109  * switching for write-protection, they are responsible for calling
 110  * mmc_gpio_request_ro() and mmc_gpio_free_ro() as a pair on their own.
 111  *
 112  * Returns zero on success, else an error.
 113  */
 114 int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
 115 {
 116         struct mmc_gpio *ctx;
 117         int ret;
 118
 119         if (!gpio_is_valid(gpio))
 120                 return -EINVAL;
 121
 122         ret = mmc_gpio_alloc(host);
 123         if (ret < 0)
 124                 return ret;
 125
 126         ctx = host->slot.handler_priv;
 127
 128         ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
 129                                     ctx->ro_label);
 130         if (ret < 0)
 131                 return ret;
 132
 133         ctx->override_ro_active_level = true;
 134         ctx->ro_gpio = gpio_to_desc(gpio);
 135
 136         return 0;
 137 }
 138 EXPORT_SYMBOL(mmc_gpio_request_ro);
 139
 140 void mmc_gpiod_request_cd_irq(struct mmc_host *host)
 141 {
 142         struct mmc_gpio *ctx = host->slot.handler_priv;
 143         int ret, irq;
 144
 145         if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio)
 146                 return;
 147
 148         irq = gpiod_to_irq(ctx->cd_gpio);
 149
 150         /*
 151          * Even if gpiod_to_irq() returns a valid IRQ number, the platform might
 152          * still prefer to poll, e.g., because that IRQ number is already used
 153          * by another unit and cannot be shared.
 154          */
 155         if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL)
 156                 irq = -EINVAL;
 157
 158         if (irq >= 0) {
 159                 ret = devm_request_threaded_irq(&host->class_dev, irq,
 160                         NULL, mmc_gpio_cd_irqt,
 161                         IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 162                         ctx->cd_label, host);
 163                 if (ret < 0)
 164                         irq = ret;
 165         }
 166
 167         host->slot.cd_irq = irq;
 168
 169         if (irq < 0)
 170                 host->caps |= MMC_CAP_NEEDS_POLL;
 171 }
 172 EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);
 173
 174 /**
 175  * mmc_gpio_request_cd - request a gpio for card-detection
 176  * @host: mmc host
 177  * @gpio: gpio number requested
 178  * @debounce: debounce time in microseconds
 179  *
 180  * As devm_* managed functions are used in mmc_gpio_request_cd(), client
 181  * drivers do not need to explicitly call mmc_gpio_free_cd() for freeing up,
 182  * if the requesting and freeing are only needed at probing and unbinding time
 183  * for once.  However, if client drivers do something special like runtime
 184  * switching for card-detection, they are responsible for calling
 185  * mmc_gpio_request_cd() and mmc_gpio_free_cd() as a pair on their own.
 186  *
 187  * If GPIO debouncing is desired, set the debounce parameter to a non-zero
 188  * value. The caller is responsible for ensuring that the GPIO driver associated
 189  * with the GPIO supports debouncing, otherwise an error will be returned.
 190  *
 191  * Returns zero on success, else an error.
 192  */
 193 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
 194                         unsigned int debounce)
 195 {
 196         struct mmc_gpio *ctx;
 197         int ret;
 198
 199         ret = mmc_gpio_alloc(host);
 200         if (ret < 0)
 201                 return ret;
 202
 203         ctx = host->slot.handler_priv;
 204
 205         ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
 206                                     ctx->cd_label);
 207         if (ret < 0)
 208                 /*
 209                  * don't bother freeing memory. It might still get used by other
 210                  * slot functions, in any case it will be freed, when the device
 211                  * is destroyed.
 212                  */
 213                 return ret;
 214
 215         if (debounce) {
 216                 ret = gpio_set_debounce(gpio, debounce);
 217                 if (ret < 0)
 218                         return ret;
 219         }
 220
 221         ctx->override_cd_active_level = true;
 222         ctx->cd_gpio = gpio_to_desc(gpio);
 223
 224         return 0;
 225 }
 226 EXPORT_SYMBOL(mmc_gpio_request_cd);
 227
 228 /**
 229  * mmc_gpio_free_ro - free the write-protection gpio
 230  * @host: mmc host
 231  *
 232  * It's provided only for cases that client drivers need to manually free
 233  * up the write-protection gpio requested by mmc_gpio_request_ro().
 234  */
 235 void mmc_gpio_free_ro(struct mmc_host *host)
 236 {
 237         struct mmc_gpio *ctx = host->slot.handler_priv;
 238         int gpio;
 239
 240         if (!ctx || !ctx->ro_gpio)
 241                 return;
 242
 243         gpio = desc_to_gpio(ctx->ro_gpio);
 244         ctx->ro_gpio = NULL;
 245
 246         devm_gpio_free(&host->class_dev, gpio);
 247 }
 248 EXPORT_SYMBOL(mmc_gpio_free_ro);
 249
 250 /**
 251  * mmc_gpio_free_cd - free the card-detection gpio
 252  * @host: mmc host
 253  *
 254  * It's provided only for cases that client drivers need to manually free
 255  * up the card-detection gpio requested by mmc_gpio_request_cd().
 256  */
 257 void mmc_gpio_free_cd(struct mmc_host *host)
 258 {
 259         struct mmc_gpio *ctx = host->slot.handler_priv;
 260         int gpio;
 261
 262         if (!ctx || !ctx->cd_gpio)
 263                 return;
 264
 265         if (host->slot.cd_irq >= 0) {
 266                 devm_free_irq(&host->class_dev, host->slot.cd_irq, host);
 267                 host->slot.cd_irq = -EINVAL;
 268         }
 269
 270         gpio = desc_to_gpio(ctx->cd_gpio);
 271         ctx->cd_gpio = NULL;
 272
 273         devm_gpio_free(&host->class_dev, gpio);
 274 }
 275 EXPORT_SYMBOL(mmc_gpio_free_cd);
 276
 277 /**
 278  * mmc_gpiod_request_cd - request a gpio descriptor for card-detection
 279  * @host: mmc host
 280  * @con_id: function within the GPIO consumer
 281  * @idx: index of the GPIO to obtain in the consumer
 282  * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
 283  * @debounce: debounce time in microseconds
 284  * @gpio_invert: will return whether the GPIO line is inverted or not, set
 285  * to NULL to ignore
 286  *
 287  * Use this function in place of mmc_gpio_request_cd() to use the GPIO
 288  * descriptor API.  Note that it is paired with mmc_gpiod_free_cd() not
 289  * mmc_gpio_free_cd().  Note also that it must be called prior to mmc_add_host()
 290  * otherwise the caller must also call mmc_gpiod_request_cd_irq().
 291  *
 292  * Returns zero on success, else an error.
 293  */
 294 int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
 295                          unsigned int idx, bool override_active_level,
 296                          unsigned int debounce, bool *gpio_invert)
 297 {
 298         struct mmc_gpio *ctx;
 299         struct gpio_desc *desc;
 300         int ret;
 301
 302         ret = mmc_gpio_alloc(host);
 303         if (ret < 0)
 304                 return ret;
 305
 306         ctx = host->slot.handler_priv;
 307
 308         if (!con_id)
 309                 con_id = ctx->cd_label;
 310
 311         desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
 312         if (IS_ERR(desc))
 313                 return PTR_ERR(desc);
 314
 315         if (debounce) {
 316                 ret = gpiod_set_debounce(desc, debounce);
 317                 if (ret < 0)
 318                         return ret;
 319         }
 320
 321         if (gpio_invert)
 322                 *gpio_invert = !gpiod_is_active_low(desc);
 323
 324         ctx->override_cd_active_level = override_active_level;
 325         ctx->cd_gpio = desc;
 326
 327         return 0;
 328 }
 329 EXPORT_SYMBOL(mmc_gpiod_request_cd);
 330
 331 /**
 332  * mmc_gpiod_request_ro - request a gpio descriptor for write protection
 333  * @host: mmc host
 334  * @con_id: function within the GPIO consumer
 335  * @idx: index of the GPIO to obtain in the consumer
 336  * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
 337  * @debounce: debounce time in microseconds
 338  * @gpio_invert: will return whether the GPIO line is inverted or not,
 339  * set to NULL to ignore
 340  *
 341  * Use this function in place of mmc_gpio_request_ro() to use the GPIO
 342  * descriptor API.  Note that it is paired with mmc_gpiod_free_ro() not
 343  * mmc_gpio_free_ro().
 344  *
 345  * Returns zero on success, else an error.
 346  */
 347 int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
 348                          unsigned int idx, bool override_active_level,
 349                          unsigned int debounce, bool *gpio_invert)
 350 {
 351         struct mmc_gpio *ctx;
 352         struct gpio_desc *desc;
 353         int ret;
 354
 355         ret = mmc_gpio_alloc(host);
 356         if (ret < 0)
 357                 return ret;
 358
 359         ctx = host->slot.handler_priv;
 360
 361         if (!con_id)
 362                 con_id = ctx->ro_label;
 363
 364         desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
 365         if (IS_ERR(desc))
 366                 return PTR_ERR(desc);
 367
 368         if (debounce) {
 369                 ret = gpiod_set_debounce(desc, debounce);
 370                 if (ret < 0)
 371                         return ret;
 372         }
 373
 374         if (gpio_invert)
 375                 *gpio_invert = !gpiod_is_active_low(desc);
 376
 377         ctx->override_ro_active_level = override_active_level;
 378         ctx->ro_gpio = desc;
 379
 380         return 0;
 381 }
 382 EXPORT_SYMBOL(mmc_gpiod_request_ro);
 383
 384 /**
 385  * mmc_gpiod_free_cd - free the card-detection gpio descriptor
 386  * @host: mmc host
 387  *
 388  * It's provided only for cases that client drivers need to manually free
 389  * up the card-detection gpio requested by mmc_gpiod_request_cd().
 390  */
 391 void mmc_gpiod_free_cd(struct mmc_host *host)
 392 {
 393         struct mmc_gpio *ctx = host->slot.handler_priv;
 394
 395         if (!ctx || !ctx->cd_gpio)
 396                 return;
 397
 398         if (host->slot.cd_irq >= 0) {
 399                 devm_free_irq(&host->class_dev, host->slot.cd_irq, host);
 400                 host->slot.cd_irq = -EINVAL;
 401         }
 402
 403         devm_gpiod_put(host->parent, ctx->cd_gpio);
 404
 405         ctx->cd_gpio = NULL;
 406 }
 407 EXPORT_SYMBOL(mmc_gpiod_free_cd);