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 if (host->ops->card_event)
36 host->ops->card_event(host);
38 mmc_detect_change(host, msecs_to_jiffies(200));
43 static int mmc_gpio_alloc(struct mmc_host *host)
45 size_t len = strlen(dev_name(host->parent)) + 4;
48 mutex_lock(&host->slot.lock);
50 ctx = host->slot.handler_priv;
53 * devm_kzalloc() can be called after device_initialize(), even
54 * before device_add(), i.e., between mmc_alloc_host() and
57 ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len,
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;
67 mutex_unlock(&host->slot.lock);
69 return ctx ? 0 : -ENOMEM;
72 int mmc_gpio_get_ro(struct mmc_host *host)
74 struct mmc_gpio *ctx = host->slot.handler_priv;
76 if (!ctx || !ctx->ro_gpio)
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);
83 return gpiod_get_value_cansleep(ctx->ro_gpio);
85 EXPORT_SYMBOL(mmc_gpio_get_ro);
87 int mmc_gpio_get_cd(struct mmc_host *host)
89 struct mmc_gpio *ctx = host->slot.handler_priv;
91 if (!ctx || !ctx->cd_gpio)
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);
98 return gpiod_get_value_cansleep(ctx->cd_gpio);
100 EXPORT_SYMBOL(mmc_gpio_get_cd);
103 * mmc_gpio_request_ro - request a gpio for write-protection
105 * @gpio: gpio number requested
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.
114 * Returns zero on success, else an error.
116 int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
118 struct mmc_gpio *ctx;
121 if (!gpio_is_valid(gpio))
124 ret = mmc_gpio_alloc(host);
128 ctx = host->slot.handler_priv;
130 ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
135 ctx->override_ro_active_level = true;
136 ctx->ro_gpio = gpio_to_desc(gpio);
140 EXPORT_SYMBOL(mmc_gpio_request_ro);
143 * mmc_gpio_request_cd - request a gpio for card-detection
145 * @gpio: gpio number requested
146 * @debounce: debounce time in microseconds
148 * As devm_* managed functions are used in mmc_gpio_request_cd(), client
149 * drivers do not need to explicitly call mmc_gpio_free_cd() for freeing up,
150 * if the requesting and freeing are only needed at probing and unbinding time
151 * for once. However, if client drivers do something special like runtime
152 * switching for card-detection, they are responsible for calling
153 * mmc_gpio_request_cd() and mmc_gpio_free_cd() as a pair on their own.
155 * If GPIO debouncing is desired, set the debounce parameter to a non-zero
156 * value. The caller is responsible for ensuring that the GPIO driver associated
157 * with the GPIO supports debouncing, otherwise an error will be returned.
159 * Returns zero on success, else an error.
161 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
162 unsigned int debounce)
164 struct mmc_gpio *ctx;
165 int irq = gpio_to_irq(gpio);
168 ret = mmc_gpio_alloc(host);
172 ctx = host->slot.handler_priv;
174 ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
178 * don't bother freeing memory. It might still get used by other
179 * slot functions, in any case it will be freed, when the device
185 ret = gpio_set_debounce(gpio, debounce);
191 * Even if gpio_to_irq() returns a valid IRQ number, the platform might
192 * still prefer to poll, e.g., because that IRQ number is already used
193 * by another unit and cannot be shared.
195 if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL)
199 ret = devm_request_threaded_irq(&host->class_dev, irq,
200 NULL, mmc_gpio_cd_irqt,
201 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
202 ctx->cd_label, host);
207 host->slot.cd_irq = irq;
210 host->caps |= MMC_CAP_NEEDS_POLL;
212 ctx->override_cd_active_level = true;
213 ctx->cd_gpio = gpio_to_desc(gpio);
217 EXPORT_SYMBOL(mmc_gpio_request_cd);
220 * mmc_gpio_free_ro - free the write-protection gpio
223 * It's provided only for cases that client drivers need to manually free
224 * up the write-protection gpio requested by mmc_gpio_request_ro().
226 void mmc_gpio_free_ro(struct mmc_host *host)
228 struct mmc_gpio *ctx = host->slot.handler_priv;
231 if (!ctx || !ctx->ro_gpio)
234 gpio = desc_to_gpio(ctx->ro_gpio);
237 devm_gpio_free(&host->class_dev, gpio);
239 EXPORT_SYMBOL(mmc_gpio_free_ro);
242 * mmc_gpio_free_cd - free the card-detection gpio
245 * It's provided only for cases that client drivers need to manually free
246 * up the card-detection gpio requested by mmc_gpio_request_cd().
248 void mmc_gpio_free_cd(struct mmc_host *host)
250 struct mmc_gpio *ctx = host->slot.handler_priv;
253 if (!ctx || !ctx->cd_gpio)
256 if (host->slot.cd_irq >= 0) {
257 devm_free_irq(&host->class_dev, host->slot.cd_irq, host);
258 host->slot.cd_irq = -EINVAL;
261 gpio = desc_to_gpio(ctx->cd_gpio);
264 devm_gpio_free(&host->class_dev, gpio);
266 EXPORT_SYMBOL(mmc_gpio_free_cd);