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 irq = -EINVAL; 125 int ret; 126 127 if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio) 128 return; 129 130 /* 131 * Do not use IRQ if the platform prefers to poll, e.g., because that 132 * IRQ number is already used by another unit and cannot be shared. 133 */ 134 if (!(host->caps & MMC_CAP_NEEDS_POLL)) 135 irq = gpiod_to_irq(ctx->cd_gpio); 136 137 if (irq >= 0) { 138 if (!ctx->cd_gpio_isr) 139 ctx->cd_gpio_isr = mmc_gpio_cd_irqt; 140 ret = devm_request_threaded_irq(host->parent, irq, 141 NULL, ctx->cd_gpio_isr, 142 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 143 ctx->cd_label, host); 144 if (ret < 0) 145 irq = ret; 146 } 147 148 host->slot.cd_irq = irq; 149 150 if (irq < 0) 151 host->caps |= MMC_CAP_NEEDS_POLL; 152 else if ((host->caps & MMC_CAP_CD_WAKE) && !enable_irq_wake(irq)) 153 host->slot.cd_wake_enabled = true; 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 desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN); 239 if (IS_ERR(desc)) 240 return PTR_ERR(desc); 241 242 if (debounce) { 243 ret = gpiod_set_debounce(desc, debounce); 244 if (ret < 0) 245 return ret; 246 } 247 248 if (gpio_invert) 249 *gpio_invert = !gpiod_is_active_low(desc); 250 251 ctx->override_cd_active_level = override_active_level; 252 ctx->cd_gpio = desc; 253 254 return 0; 255 } 256 EXPORT_SYMBOL(mmc_gpiod_request_cd); 257 258 bool mmc_can_gpio_cd(struct mmc_host *host) 259 { 260 struct mmc_gpio *ctx = host->slot.handler_priv; 261 262 return ctx->cd_gpio ? true : false; 263 } 264 EXPORT_SYMBOL(mmc_can_gpio_cd); 265 266 /** 267 * mmc_gpiod_request_ro - request a gpio descriptor for write protection 268 * @host: mmc host 269 * @con_id: function within the GPIO consumer 270 * @idx: index of the GPIO to obtain in the consumer 271 * @override_active_level: ignore %GPIO_ACTIVE_LOW flag 272 * @debounce: debounce time in microseconds 273 * @gpio_invert: will return whether the GPIO line is inverted or not, 274 * set to NULL to ignore 275 * 276 * Use this function in place of mmc_gpio_request_ro() to use the GPIO 277 * descriptor API. 278 * 279 * Returns zero on success, else an error. 280 */ 281 int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id, 282 unsigned int idx, bool override_active_level, 283 unsigned int debounce, bool *gpio_invert) 284 { 285 struct mmc_gpio *ctx = host->slot.handler_priv; 286 struct gpio_desc *desc; 287 int ret; 288 289 desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN); 290 if (IS_ERR(desc)) 291 return PTR_ERR(desc); 292 293 if (debounce) { 294 ret = gpiod_set_debounce(desc, debounce); 295 if (ret < 0) 296 return ret; 297 } 298 299 if (gpio_invert) 300 *gpio_invert = !gpiod_is_active_low(desc); 301 302 ctx->override_ro_active_level = override_active_level; 303 ctx->ro_gpio = desc; 304 305 return 0; 306 } 307 EXPORT_SYMBOL(mmc_gpiod_request_ro); 308 309 bool mmc_can_gpio_ro(struct mmc_host *host) 310 { 311 struct mmc_gpio *ctx = host->slot.handler_priv; 312 313 return ctx->ro_gpio ? true : false; 314 } 315 EXPORT_SYMBOL(mmc_can_gpio_ro); 316