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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 {
unsigned 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;
}
int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
{
size_t len = strlen(dev_name(host->parent)) + 4;
struct mmc_gpio *ctx;
int irq = gpio_to_irq(gpio);
int ret;
if (irq < 0)
return irq;
ctx = kmalloc(sizeof(*ctx) + len, GFP_KERNEL);
if (!ctx)
return -ENOMEM;
snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
ret = gpio_request_one(gpio, GPIOF_DIR_IN, ctx->cd_label);
if (ret < 0)
goto egpioreq;
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)
goto eirqreq;
ctx->cd_gpio = gpio;
host->hotplug.irq = irq;
host->hotplug.handler_priv = ctx;
return 0;
eirqreq:
gpio_free(gpio);
egpioreq:
kfree(ctx);
return ret;
}
EXPORT_SYMBOL(mmc_gpio_request_cd);
void mmc_gpio_free_cd(struct mmc_host *host)
{
struct mmc_gpio *ctx = host->hotplug.handler_priv;
if (!ctx)
return;
free_irq(host->hotplug.irq, host);
gpio_free(ctx->cd_gpio);
kfree(ctx);
}
EXPORT_SYMBOL(mmc_gpio_free_cd);
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