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