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 else if ((host->caps & MMC_CAP_CD_WAKE) && !enable_irq_wake(irq)) 155 host->slot.cd_wake_enabled = true; 156 } 157 EXPORT_SYMBOL(mmc_gpiod_request_cd_irq); 158 159 /* Register an alternate interrupt service routine for 160 * the card-detect GPIO. 161 */ 162 void mmc_gpio_set_cd_isr(struct mmc_host *host, 163 irqreturn_t (*isr)(int irq, void *dev_id)) 164 { 165 struct mmc_gpio *ctx = host->slot.handler_priv; 166 167 WARN_ON(ctx->cd_gpio_isr); 168 ctx->cd_gpio_isr = isr; 169 } 170 EXPORT_SYMBOL(mmc_gpio_set_cd_isr); 171 172 /** 173 * mmc_gpio_request_cd - request a gpio for card-detection 174 * @host: mmc host 175 * @gpio: gpio number requested 176 * @debounce: debounce time in microseconds 177 * 178 * As devm_* managed functions are used in mmc_gpio_request_cd(), client 179 * drivers do not need to worry about freeing up memory. 180 * 181 * If GPIO debouncing is desired, set the debounce parameter to a non-zero 182 * value. The caller is responsible for ensuring that the GPIO driver associated 183 * with the GPIO supports debouncing, otherwise an error will be returned. 184 * 185 * Returns zero on success, else an error. 186 */ 187 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio, 188 unsigned int debounce) 189 { 190 struct mmc_gpio *ctx = host->slot.handler_priv; 191 int ret; 192 193 ret = devm_gpio_request_one(host->parent, gpio, GPIOF_DIR_IN, 194 ctx->cd_label); 195 if (ret < 0) 196 /* 197 * don't bother freeing memory. It might still get used by other 198 * slot functions, in any case it will be freed, when the device 199 * is destroyed. 200 */ 201 return ret; 202 203 if (debounce) { 204 ret = gpio_set_debounce(gpio, debounce); 205 if (ret < 0) 206 return ret; 207 } 208 209 ctx->override_cd_active_level = true; 210 ctx->cd_gpio = gpio_to_desc(gpio); 211 212 return 0; 213 } 214 EXPORT_SYMBOL(mmc_gpio_request_cd); 215 216 /** 217 * mmc_gpiod_request_cd - request a gpio descriptor for card-detection 218 * @host: mmc host 219 * @con_id: function within the GPIO consumer 220 * @idx: index of the GPIO to obtain in the consumer 221 * @override_active_level: ignore %GPIO_ACTIVE_LOW flag 222 * @debounce: debounce time in microseconds 223 * @gpio_invert: will return whether the GPIO line is inverted or not, set 224 * to NULL to ignore 225 * 226 * Use this function in place of mmc_gpio_request_cd() to use the GPIO 227 * descriptor API. Note that it must be called prior to mmc_add_host() 228 * otherwise the caller must also call mmc_gpiod_request_cd_irq(). 229 * 230 * Returns zero on success, else an error. 231 */ 232 int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id, 233 unsigned int idx, bool override_active_level, 234 unsigned int debounce, bool *gpio_invert) 235 { 236 struct mmc_gpio *ctx = host->slot.handler_priv; 237 struct gpio_desc *desc; 238 int ret; 239 240 desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN); 241 if (IS_ERR(desc)) 242 return PTR_ERR(desc); 243 244 if (debounce) { 245 ret = gpiod_set_debounce(desc, debounce); 246 if (ret < 0) 247 return ret; 248 } 249 250 if (gpio_invert) 251 *gpio_invert = !gpiod_is_active_low(desc); 252 253 ctx->override_cd_active_level = override_active_level; 254 ctx->cd_gpio = desc; 255 256 return 0; 257 } 258 EXPORT_SYMBOL(mmc_gpiod_request_cd); 259 260 bool mmc_can_gpio_cd(struct mmc_host *host) 261 { 262 struct mmc_gpio *ctx = host->slot.handler_priv; 263 264 return ctx->cd_gpio ? true : false; 265 } 266 EXPORT_SYMBOL(mmc_can_gpio_cd); 267 268 /** 269 * mmc_gpiod_request_ro - request a gpio descriptor for write protection 270 * @host: mmc host 271 * @con_id: function within the GPIO consumer 272 * @idx: index of the GPIO to obtain in the consumer 273 * @override_active_level: ignore %GPIO_ACTIVE_LOW flag 274 * @debounce: debounce time in microseconds 275 * @gpio_invert: will return whether the GPIO line is inverted or not, 276 * set to NULL to ignore 277 * 278 * Use this function in place of mmc_gpio_request_ro() to use the GPIO 279 * descriptor API. 280 * 281 * Returns zero on success, else an error. 282 */ 283 int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id, 284 unsigned int idx, bool override_active_level, 285 unsigned int debounce, bool *gpio_invert) 286 { 287 struct mmc_gpio *ctx = host->slot.handler_priv; 288 struct gpio_desc *desc; 289 int ret; 290 291 desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN); 292 if (IS_ERR(desc)) 293 return PTR_ERR(desc); 294 295 if (debounce) { 296 ret = gpiod_set_debounce(desc, debounce); 297 if (ret < 0) 298 return ret; 299 } 300 301 if (gpio_invert) 302 *gpio_invert = !gpiod_is_active_low(desc); 303 304 ctx->override_ro_active_level = override_active_level; 305 ctx->ro_gpio = desc; 306 307 return 0; 308 } 309 EXPORT_SYMBOL(mmc_gpiod_request_ro); 310