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Commit befe4048 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Chris Ball
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mmc: add CD GPIO polling support to slot functions 



A simple extension of mmc slot functions add support for CD GPIO polling
for cases where the GPIO cannot produce interrupts, or where this is not
desired for some reason.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 5c08d7fa

drivers/mmc/core/slot-gpio.c

+43 −13
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ 
#include <linux/slab.h>



struct mmc_gpio {

	unsigned int cd_gpio;

	int cd_gpio;

	char cd_label[0];

};
@@ -29,6 +29,18 @@ static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id) 
	return IRQ_HANDLED;

}



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)

{

	size_t len = strlen(dev_name(host->parent)) + 4;
@@ -36,9 +48,6 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio) 
	int irq = gpio_to_irq(gpio);

	int ret;



	if (irq < 0)

		return irq;



	ctx = kmalloc(sizeof(*ctx) + len, GFP_KERNEL);

	if (!ctx)

		return -ENOMEM;
@@ -49,20 +58,32 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio) 
	if (ret < 0)

		goto egpioreq;



	/*

	 * 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)

		goto eirqreq;

			irq = ret;

	}



	ctx->cd_gpio = gpio;

	host->slot.cd_irq = irq;



	if (irq < 0)

		host->caps |= MMC_CAP_NEEDS_POLL;



	ctx->cd_gpio = gpio;

	host->slot.handler_priv = ctx;



	return 0;



eirqreq:

	gpio_free(gpio);

egpioreq:

	kfree(ctx);

	return ret;
@@ -72,12 +93,21 @@ 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)

	if (!ctx || !gpio_is_valid(ctx->cd_gpio))

		return;



	if (host->slot.cd_irq >= 0) {

		free_irq(host->slot.cd_irq, host);

	gpio_free(ctx->cd_gpio);

		host->slot.cd_irq = -EINVAL;

	}



	gpio = ctx->cd_gpio;

	ctx->cd_gpio = -EINVAL;



	gpio_free(gpio);

	host->slot.handler_priv = NULL;

	kfree(ctx);

}

EXPORT_SYMBOL(mmc_gpio_free_cd);

include/linux/mmc/slot-gpio.h

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#define MMC_SLOT_GPIO_H



struct mmc_host;



int mmc_gpio_get_cd(struct mmc_host *host);

int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio);

void mmc_gpio_free_cd(struct mmc_host *host);