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 mmc_gpiod_request_cd_irq(host); 225 226 return 0; 227 } 228 EXPORT_SYMBOL(mmc_gpio_request_cd); 229 230 /** 231 * mmc_gpio_free_ro - free the write-protection gpio 232 * @host: mmc host 233 * 234 * It's provided only for cases that client drivers need to manually free 235 * up the write-protection gpio requested by mmc_gpio_request_ro(). 236 */ 237 void mmc_gpio_free_ro(struct mmc_host *host) 238 { 239 struct mmc_gpio *ctx = host->slot.handler_priv; 240 int gpio; 241 242 if (!ctx || !ctx->ro_gpio) 243 return; 244 245 gpio = desc_to_gpio(ctx->ro_gpio); 246 ctx->ro_gpio = NULL; 247 248 devm_gpio_free(&host->class_dev, gpio); 249 } 250 EXPORT_SYMBOL(mmc_gpio_free_ro); 251 252 /** 253 * mmc_gpio_free_cd - free the card-detection gpio 254 * @host: mmc host 255 * 256 * It's provided only for cases that client drivers need to manually free 257 * up the card-detection gpio requested by mmc_gpio_request_cd(). 258 */ 259 void mmc_gpio_free_cd(struct mmc_host *host) 260 { 261 struct mmc_gpio *ctx = host->slot.handler_priv; 262 int gpio; 263 264 if (!ctx || !ctx->cd_gpio) 265 return; 266 267 if (host->slot.cd_irq >= 0) { 268 devm_free_irq(&host->class_dev, host->slot.cd_irq, host); 269 host->slot.cd_irq = -EINVAL; 270 } 271 272 gpio = desc_to_gpio(ctx->cd_gpio); 273 ctx->cd_gpio = NULL; 274 275 devm_gpio_free(&host->class_dev, gpio); 276 } 277 EXPORT_SYMBOL(mmc_gpio_free_cd); 278 279 /** 280 * mmc_gpiod_request_cd - request a gpio descriptor for card-detection 281 * @host: mmc host 282 * @con_id: function within the GPIO consumer 283 * @idx: index of the GPIO to obtain in the consumer 284 * @override_active_level: ignore %GPIO_ACTIVE_LOW flag 285 * @debounce: debounce time in microseconds 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) 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); 312 if (IS_ERR(desc)) 313 return PTR_ERR(desc); 314 315 ret = gpiod_direction_input(desc); 316 if (ret < 0) 317 return ret; 318 319 if (debounce) { 320 ret = gpiod_set_debounce(desc, debounce); 321 if (ret < 0) 322 return ret; 323 } 324 325 ctx->override_cd_active_level = override_active_level; 326 ctx->cd_gpio = desc; 327 328 return 0; 329 } 330 EXPORT_SYMBOL(mmc_gpiod_request_cd); 331 332 /** 333 * mmc_gpiod_free_cd - free the card-detection gpio descriptor 334 * @host: mmc host 335 * 336 * It's provided only for cases that client drivers need to manually free 337 * up the card-detection gpio requested by mmc_gpiod_request_cd(). 338 */ 339 void mmc_gpiod_free_cd(struct mmc_host *host) 340 { 341 struct mmc_gpio *ctx = host->slot.handler_priv; 342 343 if (!ctx || !ctx->cd_gpio) 344 return; 345 346 if (host->slot.cd_irq >= 0) { 347 devm_free_irq(&host->class_dev, host->slot.cd_irq, host); 348 host->slot.cd_irq = -EINVAL; 349 } 350 351 devm_gpiod_put(&host->class_dev, ctx->cd_gpio); 352 353 ctx->cd_gpio = NULL; 354 } 355 EXPORT_SYMBOL(mmc_gpiod_free_cd); 356