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); 408