2 * Generic GPIO card-detect helper
4 * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
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.
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>
22 struct gpio_desc *ro_gpio;
23 struct gpio_desc *cd_gpio;
24 bool override_ro_active_level;
25 bool override_cd_active_level;
30 static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
32 /* Schedule a card detection after a debounce timeout */
33 struct mmc_host *host = dev_id;
35 host->trigger_card_event = true;
36 mmc_detect_change(host, msecs_to_jiffies(200));
41 static int mmc_gpio_alloc(struct mmc_host *host)
43 size_t len = strlen(dev_name(host->parent)) + 4;
46 mutex_lock(&host->slot.lock);
48 ctx = host->slot.handler_priv;
51 * devm_kzalloc() can be called after device_initialize(), even
52 * before device_add(), i.e., between mmc_alloc_host() and
55 ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len,
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;
65 mutex_unlock(&host->slot.lock);
67 return ctx ? 0 : -ENOMEM;
70 int mmc_gpio_get_ro(struct mmc_host *host)
72 struct mmc_gpio *ctx = host->slot.handler_priv;
74 if (!ctx || !ctx->ro_gpio)
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);
81 return gpiod_get_value_cansleep(ctx->ro_gpio);
83 EXPORT_SYMBOL(mmc_gpio_get_ro);
85 int mmc_gpio_get_cd(struct mmc_host *host)
87 struct mmc_gpio *ctx = host->slot.handler_priv;
89 if (!ctx || !ctx->cd_gpio)
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);
96 return gpiod_get_value_cansleep(ctx->cd_gpio);
98 EXPORT_SYMBOL(mmc_gpio_get_cd);
101 * mmc_gpio_request_ro - request a gpio for write-protection
103 * @gpio: gpio number requested
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.
112 * Returns zero on success, else an error.
114 int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
116 struct mmc_gpio *ctx;
119 if (!gpio_is_valid(gpio))
122 ret = mmc_gpio_alloc(host);
126 ctx = host->slot.handler_priv;
128 ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
133 ctx->override_ro_active_level = true;
134 ctx->ro_gpio = gpio_to_desc(gpio);
138 EXPORT_SYMBOL(mmc_gpio_request_ro);
140 void mmc_gpiod_request_cd_irq(struct mmc_host *host)
142 struct mmc_gpio *ctx = host->slot.handler_priv;
145 if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio)
148 irq = gpiod_to_irq(ctx->cd_gpio);
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.
155 if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL)
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);
167 host->slot.cd_irq = irq;
170 host->caps |= MMC_CAP_NEEDS_POLL;
172 EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);
175 * mmc_gpio_request_cd - request a gpio for card-detection
177 * @gpio: gpio number requested
178 * @debounce: debounce time in microseconds
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.
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.
191 * Returns zero on success, else an error.
193 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
194 unsigned int debounce)
196 struct mmc_gpio *ctx;
199 ret = mmc_gpio_alloc(host);
203 ctx = host->slot.handler_priv;
205 ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
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
216 ret = gpio_set_debounce(gpio, debounce);
221 ctx->override_cd_active_level = true;
222 ctx->cd_gpio = gpio_to_desc(gpio);
224 mmc_gpiod_request_cd_irq(host);
228 EXPORT_SYMBOL(mmc_gpio_request_cd);
231 * mmc_gpio_free_ro - free the write-protection gpio
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().
237 void mmc_gpio_free_ro(struct mmc_host *host)
239 struct mmc_gpio *ctx = host->slot.handler_priv;
242 if (!ctx || !ctx->ro_gpio)
245 gpio = desc_to_gpio(ctx->ro_gpio);
248 devm_gpio_free(&host->class_dev, gpio);
250 EXPORT_SYMBOL(mmc_gpio_free_ro);
253 * mmc_gpio_free_cd - free the card-detection gpio
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().
259 void mmc_gpio_free_cd(struct mmc_host *host)
261 struct mmc_gpio *ctx = host->slot.handler_priv;
264 if (!ctx || !ctx->cd_gpio)
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;
272 gpio = desc_to_gpio(ctx->cd_gpio);
275 devm_gpio_free(&host->class_dev, gpio);
277 EXPORT_SYMBOL(mmc_gpio_free_cd);
280 * mmc_gpiod_request_cd - request a gpio descriptor for card-detection
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
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().
292 * Returns zero on success, else an error.
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)
298 struct mmc_gpio *ctx;
299 struct gpio_desc *desc;
302 ret = mmc_gpio_alloc(host);
306 ctx = host->slot.handler_priv;
309 con_id = ctx->cd_label;
311 desc = devm_gpiod_get_index(host->parent, con_id, idx);
313 return PTR_ERR(desc);
315 ret = gpiod_direction_input(desc);
320 ret = gpiod_set_debounce(desc, debounce);
325 ctx->override_cd_active_level = override_active_level;
330 EXPORT_SYMBOL(mmc_gpiod_request_cd);
333 * mmc_gpiod_free_cd - free the card-detection gpio descriptor
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().
339 void mmc_gpiod_free_cd(struct mmc_host *host)
341 struct mmc_gpio *ctx = host->slot.handler_priv;
343 if (!ctx || !ctx->cd_gpio)
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;
351 devm_gpiod_put(&host->class_dev, ctx->cd_gpio);
355 EXPORT_SYMBOL(mmc_gpiod_free_cd);