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 #include "slot-gpio.h"
  22
  23 struct mmc_gpio {
  24         struct gpio_desc *ro_gpio;
  25         struct gpio_desc *cd_gpio;
  26         bool override_ro_active_level;
  27         bool override_cd_active_level;
  28         irqreturn_t (*cd_gpio_isr)(int irq, void *dev_id);
  29         char *ro_label;
  30         u32 cd_debounce_delay_ms;
  31         char cd_label[];
  32 };
  33
  34 static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
  35 {
  36         /* Schedule a card detection after a debounce timeout */
  37         struct mmc_host *host = dev_id;
  38         struct mmc_gpio *ctx = host->slot.handler_priv;
  39
  40         host->trigger_card_event = true;
  41         mmc_detect_change(host, msecs_to_jiffies(ctx->cd_debounce_delay_ms));
  42
  43         return IRQ_HANDLED;
  44 }
  45
  46 int mmc_gpio_alloc(struct mmc_host *host)
  47 {
  48         size_t len = strlen(dev_name(host->parent)) + 4;
  49         struct mmc_gpio *ctx = devm_kzalloc(host->parent,
  50                                 sizeof(*ctx) + 2 * len, GFP_KERNEL);
  51
  52         if (ctx) {
  53                 ctx->ro_label = ctx->cd_label + len;
  54                 ctx->cd_debounce_delay_ms = 200;
  55                 snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
  56                 snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent));
  57                 host->slot.handler_priv = ctx;
  58                 host->slot.cd_irq = -EINVAL;
  59         }
  60
  61         return ctx ? 0 : -ENOMEM;
  62 }
  63
  64 int mmc_gpio_get_ro(struct mmc_host *host)
  65 {
  66         struct mmc_gpio *ctx = host->slot.handler_priv;
  67
  68         if (!ctx || !ctx->ro_gpio)
  69                 return -ENOSYS;
  70
  71         if (ctx->override_ro_active_level)
  72                 return !gpiod_get_raw_value_cansleep(ctx->ro_gpio) ^
  73                         !!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH);
  74
  75         return gpiod_get_value_cansleep(ctx->ro_gpio);
  76 }
  77 EXPORT_SYMBOL(mmc_gpio_get_ro);
  78
  79 int mmc_gpio_get_cd(struct mmc_host *host)
  80 {
  81         struct mmc_gpio *ctx = host->slot.handler_priv;
  82         int cansleep;
  83
  84         if (!ctx || !ctx->cd_gpio)
  85                 return -ENOSYS;
  86
  87         cansleep = gpiod_cansleep(ctx->cd_gpio);
  88         if (ctx->override_cd_active_level) {
  89                 int value = cansleep ?
  90                                 gpiod_get_raw_value_cansleep(ctx->cd_gpio) :
  91                                 gpiod_get_raw_value(ctx->cd_gpio);
  92                 return !value ^ !!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
  93         }
  94
  95         return cansleep ?
  96                 gpiod_get_value_cansleep(ctx->cd_gpio) :
  97                 gpiod_get_value(ctx->cd_gpio);
  98 }
  99 EXPORT_SYMBOL(mmc_gpio_get_cd);
 100
 101 /**
 102  * mmc_gpio_request_ro - request a gpio for write-protection
 103  * @host: mmc host
 104  * @gpio: gpio number requested
 105  *
 106  * As devm_* managed functions are used in mmc_gpio_request_ro(), client
 107  * drivers do not need to worry about freeing up memory.
 108  *
 109  * Returns zero on success, else an error.
 110  */
 111 int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
 112 {
 113         struct mmc_gpio *ctx = host->slot.handler_priv;
 114         int ret;
 115
 116         if (!gpio_is_valid(gpio))
 117                 return -EINVAL;
 118
 119         ret = devm_gpio_request_one(host->parent, gpio, GPIOF_DIR_IN,
 120                                     ctx->ro_label);
 121         if (ret < 0)
 122                 return ret;
 123
 124         ctx->override_ro_active_level = true;
 125         ctx->ro_gpio = gpio_to_desc(gpio);
 126
 127         return 0;
 128 }
 129 EXPORT_SYMBOL(mmc_gpio_request_ro);
 130
 131 void mmc_gpiod_request_cd_irq(struct mmc_host *host)
 132 {
 133         struct mmc_gpio *ctx = host->slot.handler_priv;
 134         int irq = -EINVAL;
 135         int ret;
 136
 137         if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio)
 138                 return;
 139
 140         /*
 141          * Do not use IRQ if the platform prefers to poll, e.g., because that
 142          * IRQ number is already used by another unit and cannot be shared.
 143          */
 144         if (!(host->caps & MMC_CAP_NEEDS_POLL))
 145                 irq = gpiod_to_irq(ctx->cd_gpio);
 146
 147         if (irq >= 0) {
 148                 if (!ctx->cd_gpio_isr)
 149                         ctx->cd_gpio_isr = mmc_gpio_cd_irqt;
 150                 ret = devm_request_threaded_irq(host->parent, irq,
 151                         NULL, ctx->cd_gpio_isr,
 152                         IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 153                         ctx->cd_label, host);
 154                 if (ret < 0)
 155                         irq = ret;
 156         }
 157
 158         host->slot.cd_irq = irq;
 159
 160         if (irq < 0)
 161                 host->caps |= MMC_CAP_NEEDS_POLL;
 162 }
 163 EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);
 164
 165 int mmc_gpio_set_cd_wake(struct mmc_host *host, bool on)
 166 {
 167         int ret = 0;
 168
 169         if (!(host->caps & MMC_CAP_CD_WAKE) ||
 170             host->slot.cd_irq < 0 ||
 171             on == host->slot.cd_wake_enabled)
 172                 return 0;
 173
 174         if (on) {
 175                 ret = enable_irq_wake(host->slot.cd_irq);
 176                 host->slot.cd_wake_enabled = !ret;
 177         } else {
 178                 disable_irq_wake(host->slot.cd_irq);
 179                 host->slot.cd_wake_enabled = false;
 180         }
 181
 182         return ret;
 183 }
 184 EXPORT_SYMBOL(mmc_gpio_set_cd_wake);
 185
 186 /* Register an alternate interrupt service routine for
 187  * the card-detect GPIO.
 188  */
 189 void mmc_gpio_set_cd_isr(struct mmc_host *host,
 190                          irqreturn_t (*isr)(int irq, void *dev_id))
 191 {
 192         struct mmc_gpio *ctx = host->slot.handler_priv;
 193
 194         WARN_ON(ctx->cd_gpio_isr);
 195         ctx->cd_gpio_isr = isr;
 196 }
 197 EXPORT_SYMBOL(mmc_gpio_set_cd_isr);
 198
 199 /**
 200  * mmc_gpio_request_cd - request a gpio for card-detection
 201  * @host: mmc host
 202  * @gpio: gpio number requested
 203  * @debounce: debounce time in microseconds
 204  *
 205  * As devm_* managed functions are used in mmc_gpio_request_cd(), client
 206  * drivers do not need to worry about freeing up memory.
 207  *
 208  * If GPIO debouncing is desired, set the debounce parameter to a non-zero
 209  * value. The caller is responsible for ensuring that the GPIO driver associated
 210  * with the GPIO supports debouncing, otherwise an error will be returned.
 211  *
 212  * Returns zero on success, else an error.
 213  */
 214 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
 215                         unsigned int debounce)
 216 {
 217         struct mmc_gpio *ctx = host->slot.handler_priv;
 218         int ret;
 219
 220         ret = devm_gpio_request_one(host->parent, gpio, GPIOF_DIR_IN,
 221                                     ctx->cd_label);
 222         if (ret < 0)
 223                 /*
 224                  * don't bother freeing memory. It might still get used by other
 225                  * slot functions, in any case it will be freed, when the device
 226                  * is destroyed.
 227                  */
 228                 return ret;
 229
 230         if (debounce) {
 231                 ret = gpio_set_debounce(gpio, debounce);
 232                 if (ret < 0)
 233                         return ret;
 234         }
 235
 236         ctx->override_cd_active_level = true;
 237         ctx->cd_gpio = gpio_to_desc(gpio);
 238
 239         return 0;
 240 }
 241 EXPORT_SYMBOL(mmc_gpio_request_cd);
 242
 243 /**
 244  * mmc_gpiod_request_cd - request a gpio descriptor for card-detection
 245  * @host: mmc host
 246  * @con_id: function within the GPIO consumer
 247  * @idx: index of the GPIO to obtain in the consumer
 248  * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
 249  * @debounce: debounce time in microseconds
 250  * @gpio_invert: will return whether the GPIO line is inverted or not, set
 251  * to NULL to ignore
 252  *
 253  * Use this function in place of mmc_gpio_request_cd() to use the GPIO
 254  * descriptor API.  Note that it must be called prior to mmc_add_host()
 255  * otherwise the caller must also call mmc_gpiod_request_cd_irq().
 256  *
 257  * Returns zero on success, else an error.
 258  */
 259 int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
 260                          unsigned int idx, bool override_active_level,
 261                          unsigned int debounce, bool *gpio_invert)
 262 {
 263         struct mmc_gpio *ctx = host->slot.handler_priv;
 264         struct gpio_desc *desc;
 265         int ret;
 266
 267         desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
 268         if (IS_ERR(desc))
 269                 return PTR_ERR(desc);
 270
 271         if (debounce) {
 272                 ret = gpiod_set_debounce(desc, debounce);
 273                 if (ret < 0)
 274                         ctx->cd_debounce_delay_ms = debounce / 1000;
 275         }
 276
 277         if (gpio_invert)
 278                 *gpio_invert = !gpiod_is_active_low(desc);
 279
 280         ctx->override_cd_active_level = override_active_level;
 281         ctx->cd_gpio = desc;
 282
 283         return 0;
 284 }
 285 EXPORT_SYMBOL(mmc_gpiod_request_cd);
 286
 287 bool mmc_can_gpio_cd(struct mmc_host *host)
 288 {
 289         struct mmc_gpio *ctx = host->slot.handler_priv;
 290
 291         return ctx->cd_gpio ? true : false;
 292 }
 293 EXPORT_SYMBOL(mmc_can_gpio_cd);
 294
 295 /**
 296  * mmc_gpiod_request_ro - request a gpio descriptor for write protection
 297  * @host: mmc host
 298  * @con_id: function within the GPIO consumer
 299  * @idx: index of the GPIO to obtain in the consumer
 300  * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
 301  * @debounce: debounce time in microseconds
 302  * @gpio_invert: will return whether the GPIO line is inverted or not,
 303  * set to NULL to ignore
 304  *
 305  * Use this function in place of mmc_gpio_request_ro() to use the GPIO
 306  * descriptor API.
 307  *
 308  * Returns zero on success, else an error.
 309  */
 310 int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
 311                          unsigned int idx, bool override_active_level,
 312                          unsigned int debounce, bool *gpio_invert)
 313 {
 314         struct mmc_gpio *ctx = host->slot.handler_priv;
 315         struct gpio_desc *desc;
 316         int ret;
 317
 318         desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
 319         if (IS_ERR(desc))
 320                 return PTR_ERR(desc);
 321
 322         if (debounce) {
 323                 ret = gpiod_set_debounce(desc, debounce);
 324                 if (ret < 0)
 325                         return ret;
 326         }
 327
 328         if (gpio_invert)
 329                 *gpio_invert = !gpiod_is_active_low(desc);
 330
 331         ctx->override_ro_active_level = override_active_level;
 332         ctx->ro_gpio = desc;
 333
 334         return 0;
 335 }
 336 EXPORT_SYMBOL(mmc_gpiod_request_ro);
 337
 338 bool mmc_can_gpio_ro(struct mmc_host *host)
 339 {
 340         struct mmc_gpio *ctx = host->slot.handler_priv;
 341
 342         return ctx->ro_gpio ? true : false;
 343 }
 344 EXPORT_SYMBOL(mmc_can_gpio_ro);