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/interrupt.h>
14 #include <linux/jiffies.h>
15 #include <linux/mmc/host.h>
16 #include <linux/mmc/slot-gpio.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
27 static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
29 /* Schedule a card detection after a debounce timeout */
30 struct mmc_host *host = dev_id;
32 if (host->ops->card_event)
33 host->ops->card_event(host);
35 mmc_detect_change(host, msecs_to_jiffies(200));
40 static int mmc_gpio_alloc(struct mmc_host *host)
42 size_t len = strlen(dev_name(host->parent)) + 4;
45 mutex_lock(&host->slot.lock);
47 ctx = host->slot.handler_priv;
50 * devm_kzalloc() can be called after device_initialize(), even
51 * before device_add(), i.e., between mmc_alloc_host() and
54 ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len,
57 ctx->ro_label = ctx->cd_label + len;
58 snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
59 snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent));
60 ctx->cd_gpio = -EINVAL;
61 ctx->ro_gpio = -EINVAL;
62 host->slot.handler_priv = ctx;
66 mutex_unlock(&host->slot.lock);
68 return ctx ? 0 : -ENOMEM;
71 int mmc_gpio_get_ro(struct mmc_host *host)
73 struct mmc_gpio *ctx = host->slot.handler_priv;
75 if (!ctx || !gpio_is_valid(ctx->ro_gpio))
78 return !gpio_get_value_cansleep(ctx->ro_gpio) ^
79 !!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH);
81 EXPORT_SYMBOL(mmc_gpio_get_ro);
83 int mmc_gpio_get_cd(struct mmc_host *host)
85 struct mmc_gpio *ctx = host->slot.handler_priv;
87 if (!ctx || !gpio_is_valid(ctx->cd_gpio))
90 return !gpio_get_value_cansleep(ctx->cd_gpio) ^
91 !!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
93 EXPORT_SYMBOL(mmc_gpio_get_cd);
96 * mmc_gpio_request_ro - request a gpio for write-protection
98 * @gpio: gpio number requested
100 * As devm_* managed functions are used in mmc_gpio_request_ro(), client
101 * drivers do not need to explicitly call mmc_gpio_free_ro() for freeing up,
102 * if the requesting and freeing are only needed at probing and unbinding time
103 * for once. However, if client drivers do something special like runtime
104 * switching for write-protection, they are responsible for calling
105 * mmc_gpio_request_ro() and mmc_gpio_free_ro() as a pair on their own.
107 * Returns zero on success, else an error.
109 int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
111 struct mmc_gpio *ctx;
114 if (!gpio_is_valid(gpio))
117 ret = mmc_gpio_alloc(host);
121 ctx = host->slot.handler_priv;
123 ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
132 EXPORT_SYMBOL(mmc_gpio_request_ro);
135 * mmc_gpio_request_cd - request a gpio for card-detection
137 * @gpio: gpio number requested
139 * As devm_* managed functions are used in mmc_gpio_request_cd(), client
140 * drivers do not need to explicitly call mmc_gpio_free_cd() for freeing up,
141 * if the requesting and freeing are only needed at probing and unbinding time
142 * for once. However, if client drivers do something special like runtime
143 * switching for card-detection, they are responsible for calling
144 * mmc_gpio_request_cd() and mmc_gpio_free_cd() as a pair on their own.
146 * Returns zero on success, else an error.
148 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
150 struct mmc_gpio *ctx;
151 int irq = gpio_to_irq(gpio);
154 ret = mmc_gpio_alloc(host);
158 ctx = host->slot.handler_priv;
160 ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
164 * don't bother freeing memory. It might still get used by other
165 * slot functions, in any case it will be freed, when the device
171 * Even if gpio_to_irq() returns a valid IRQ number, the platform might
172 * still prefer to poll, e.g., because that IRQ number is already used
173 * by another unit and cannot be shared.
175 if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL)
179 ret = devm_request_threaded_irq(&host->class_dev, irq,
180 NULL, mmc_gpio_cd_irqt,
181 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
182 ctx->cd_label, host);
187 host->slot.cd_irq = irq;
190 host->caps |= MMC_CAP_NEEDS_POLL;
196 EXPORT_SYMBOL(mmc_gpio_request_cd);
199 * mmc_gpio_free_ro - free the write-protection gpio
202 * It's provided only for cases that client drivers need to manually free
203 * up the write-protection gpio requested by mmc_gpio_request_ro().
205 void mmc_gpio_free_ro(struct mmc_host *host)
207 struct mmc_gpio *ctx = host->slot.handler_priv;
210 if (!ctx || !gpio_is_valid(ctx->ro_gpio))
214 ctx->ro_gpio = -EINVAL;
216 devm_gpio_free(&host->class_dev, gpio);
218 EXPORT_SYMBOL(mmc_gpio_free_ro);
221 * mmc_gpio_free_cd - free the card-detection gpio
224 * It's provided only for cases that client drivers need to manually free
225 * up the card-detection gpio requested by mmc_gpio_request_cd().
227 void mmc_gpio_free_cd(struct mmc_host *host)
229 struct mmc_gpio *ctx = host->slot.handler_priv;
232 if (!ctx || !gpio_is_valid(ctx->cd_gpio))
235 if (host->slot.cd_irq >= 0) {
236 devm_free_irq(&host->class_dev, host->slot.cd_irq, host);
237 host->slot.cd_irq = -EINVAL;
241 ctx->cd_gpio = -EINVAL;
243 devm_gpio_free(&host->class_dev, gpio);
245 EXPORT_SYMBOL(mmc_gpio_free_cd);