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