/* * Generic GPIO card-detect helper * * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/err.h> #include <linux/gpio.h> #include <linux/interrupt.h> #include <linux/jiffies.h> #include <linux/mmc/host.h> #include <linux/mmc/slot-gpio.h> #include <linux/module.h> #include <linux/slab.h> struct mmc_gpio { int ro_gpio; int cd_gpio; char *ro_label; char cd_label[0]; }; static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id) { /* Schedule a card detection after a debounce timeout */ struct mmc_host *host = dev_id; if (host->ops->card_event) host->ops->card_event(host); mmc_detect_change(host, msecs_to_jiffies(200)); return IRQ_HANDLED; } static int mmc_gpio_alloc(struct mmc_host *host) { size_t len = strlen(dev_name(host->parent)) + 4; struct mmc_gpio *ctx; mutex_lock(&host->slot.lock); ctx = host->slot.handler_priv; if (!ctx) { /* * devm_kzalloc() can be called after device_initialize(), even * before device_add(), i.e., between mmc_alloc_host() and * mmc_add_host() */ ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len, GFP_KERNEL); if (ctx) { ctx->ro_label = ctx->cd_label + len; snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent)); snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent)); ctx->cd_gpio = -EINVAL; ctx->ro_gpio = -EINVAL; host->slot.handler_priv = ctx; } } mutex_unlock(&host->slot.lock); return ctx ? 0 : -ENOMEM; } int mmc_gpio_get_ro(struct mmc_host *host) { struct mmc_gpio *ctx = host->slot.handler_priv; if (!ctx || !gpio_is_valid(ctx->ro_gpio)) return -ENOSYS; return !gpio_get_value_cansleep(ctx->ro_gpio) ^ !!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH); } EXPORT_SYMBOL(mmc_gpio_get_ro); int mmc_gpio_get_cd(struct mmc_host *host) { struct mmc_gpio *ctx = host->slot.handler_priv; if (!ctx || !gpio_is_valid(ctx->cd_gpio)) return -ENOSYS; return !gpio_get_value_cansleep(ctx->cd_gpio) ^ !!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH); } EXPORT_SYMBOL(mmc_gpio_get_cd); /** * mmc_gpio_request_ro - request a gpio for write-protection * @host: mmc host * @gpio: gpio number requested * * As devm_* managed functions are used in mmc_gpio_request_ro(), client * drivers do not need to explicitly call mmc_gpio_free_ro() for freeing up, * if the requesting and freeing are only needed at probing and unbinding time * for once. However, if client drivers do something special like runtime * switching for write-protection, they are responsible for calling * mmc_gpio_request_ro() and mmc_gpio_free_ro() as a pair on their own. * * Returns zero on success, else an error. */ int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio) { struct mmc_gpio *ctx; int ret; if (!gpio_is_valid(gpio)) return -EINVAL; ret = mmc_gpio_alloc(host); if (ret < 0) return ret; ctx = host->slot.handler_priv; ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN, ctx->ro_label); if (ret < 0) return ret; ctx->ro_gpio = gpio; return 0; } EXPORT_SYMBOL(mmc_gpio_request_ro); /** * mmc_gpio_request_cd - request a gpio for card-detection * @host: mmc host * @gpio: gpio number requested * @debounce: debounce time in microseconds * * As devm_* managed functions are used in mmc_gpio_request_cd(), client * drivers do not need to explicitly call mmc_gpio_free_cd() for freeing up, * if the requesting and freeing are only needed at probing and unbinding time * for once. However, if client drivers do something special like runtime * switching for card-detection, they are responsible for calling * mmc_gpio_request_cd() and mmc_gpio_free_cd() as a pair on their own. * * If GPIO debouncing is desired, set the debounce parameter to a non-zero * value. The caller is responsible for ensuring that the GPIO driver associated * with the GPIO supports debouncing, otherwise an error will be returned. * * Returns zero on success, else an error. */ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio, unsigned int debounce) { struct mmc_gpio *ctx; int irq = gpio_to_irq(gpio); int ret; ret = mmc_gpio_alloc(host); if (ret < 0) return ret; ctx = host->slot.handler_priv; ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN, ctx->cd_label); if (ret < 0) /* * don't bother freeing memory. It might still get used by other * slot functions, in any case it will be freed, when the device * is destroyed. */ return ret; if (debounce) { ret = gpio_set_debounce(gpio, debounce); if (ret < 0) return ret; } /* * Even if gpio_to_irq() returns a valid IRQ number, the platform might * still prefer to poll, e.g., because that IRQ number is already used * by another unit and cannot be shared. */ if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL) irq = -EINVAL; if (irq >= 0) { ret = devm_request_threaded_irq(&host->class_dev, irq, NULL, mmc_gpio_cd_irqt, IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT, ctx->cd_label, host); if (ret < 0) irq = ret; } host->slot.cd_irq = irq; if (irq < 0) host->caps |= MMC_CAP_NEEDS_POLL; ctx->cd_gpio = gpio; return 0; } EXPORT_SYMBOL(mmc_gpio_request_cd); /** * mmc_gpio_free_ro - free the write-protection gpio * @host: mmc host * * It's provided only for cases that client drivers need to manually free * up the write-protection gpio requested by mmc_gpio_request_ro(). */ void mmc_gpio_free_ro(struct mmc_host *host) { struct mmc_gpio *ctx = host->slot.handler_priv; int gpio; if (!ctx || !gpio_is_valid(ctx->ro_gpio)) return; gpio = ctx->ro_gpio; ctx->ro_gpio = -EINVAL; devm_gpio_free(&host->class_dev, gpio); } EXPORT_SYMBOL(mmc_gpio_free_ro); /** * mmc_gpio_free_cd - free the card-detection gpio * @host: mmc host * * It's provided only for cases that client drivers need to manually free * up the card-detection gpio requested by mmc_gpio_request_cd(). */ void mmc_gpio_free_cd(struct mmc_host *host) { struct mmc_gpio *ctx = host->slot.handler_priv; int gpio; if (!ctx || !gpio_is_valid(ctx->cd_gpio)) return; if (host->slot.cd_irq >= 0) { devm_free_irq(&host->class_dev, host->slot.cd_irq, host); host->slot.cd_irq = -EINVAL; } gpio = ctx->cd_gpio; ctx->cd_gpio = -EINVAL; devm_gpio_free(&host->class_dev, gpio); } EXPORT_SYMBOL(mmc_gpio_free_cd);