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/*
* 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 cd_gpio;
char cd_label[0];
};
static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
{
/* Schedule a card detection after a debounce timeout */
mmc_detect_change(dev_id, msecs_to_jiffies(100));
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) + len,
GFP_KERNEL);
if (ctx) {
snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
ctx->cd_gpio = -EINVAL;
host->slot.handler_priv = ctx;
}
}
mutex_unlock(&host->slot.lock);
return ctx ? 0 : -ENOMEM;
}
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);
int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
{
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 = gpio_request_one(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;
/*
* 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 = request_threaded_irq(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);
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) {
free_irq(host->slot.cd_irq, host);
host->slot.cd_irq = -EINVAL;
}
gpio = ctx->cd_gpio;
ctx->cd_gpio = -EINVAL;
gpio_free(gpio);
}
EXPORT_SYMBOL(mmc_gpio_free_cd);
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