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); 358