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Commit 349ab524 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Chris Ball
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mmc: add a generic GPIO card-detect helper 



This patch adds a primitive helper to support card hotplug detection on
platforms, where a GPIO, capable of producing interrupts, is used for
detection of card-insertion and -removal events.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent b67e1980

drivers/mmc/core/Makefile

+1 −1
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@@ -7,6 +7,6 @@ mmc_core-y := core.o bus.o host.o \ 
				   mmc.o mmc_ops.o sd.o sd_ops.o \

				   mmc.o mmc_ops.o sd.o sd_ops.o \

				   sdio.o sdio_ops.o sdio_bus.o \

				   sdio.o sdio_ops.o sdio_bus.o \

				   sdio_cis.o sdio_io.o sdio_irq.o \

				   sdio_cis.o sdio_io.o sdio_irq.o \

				   quirks.o

				   quirks.o cd-gpio.o





mmc_core-$(CONFIG_DEBUG_FS)	+= debugfs.o
 
mmc_core-$(CONFIG_DEBUG_FS)	+= debugfs.o

drivers/mmc/core/cd-gpio.c

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+74 −0
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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/module.h>

#include <linux/slab.h>



struct mmc_cd_gpio {

	unsigned int gpio;

	char label[0];

};



static irqreturn_t mmc_cd_gpio_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_cd_gpio_request(struct mmc_host *host, unsigned int gpio,

			unsigned int irq, unsigned long flags)

{

	size_t len = strlen(dev_name(host->parent)) + 4;

	struct mmc_cd_gpio *cd = kmalloc(sizeof(*cd) + len, GFP_KERNEL);

	int ret;



	if (!cd)

		return -ENOMEM;



	snprintf(cd->label, len, "%s cd", dev_name(host->parent));



	ret = gpio_request_one(gpio, GPIOF_DIR_IN, cd->label);

	if (ret < 0)

		goto egpioreq;



	ret = request_threaded_irq(irq, NULL, mmc_cd_gpio_irqt,

				   flags, cd->label, host);

	if (ret < 0)

		goto eirqreq;



	cd->gpio = gpio;

	host->hotplug.irq = irq;

	host->hotplug.handler_priv = cd;



	return 0;



eirqreq:

	gpio_free(gpio);

egpioreq:

	kfree(cd);

	return ret;

}

EXPORT_SYMBOL(mmc_cd_gpio_request);



void mmc_cd_gpio_free(struct mmc_host *host)

{

	struct mmc_cd_gpio *cd = host->hotplug.handler_priv;



	free_irq(host->hotplug.irq, host);

	gpio_free(cd->gpio);

	kfree(cd);

}

EXPORT_SYMBOL(mmc_cd_gpio_free);

include/linux/mmc/cd-gpio.h

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Original line number Original line Diff line number Diff line 
/*

 * Generic GPIO card-detect helper header

 *

 * 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.

 */



#ifndef MMC_CD_GPIO_H

#define MMC_CD_GPIO_H



struct mmc_host;

int mmc_cd_gpio_request(struct mmc_host *host, unsigned int gpio,

			unsigned int irq, unsigned long flags);

void mmc_cd_gpio_free(struct mmc_host *host);



#endif