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