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mmc: add CD GPIO polling support to slot functions

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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: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Guennadi Liakhovetski 2012-05-01 16:27:25 +02:00 committed by Chris Ball
parent 5c08d7fae0
commit befe4048d8
2 changed files with 45 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

56
drivers/mmc/core/slot-gpio.c
View file

@ -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;
ret = request_threaded_irq(irq, NULL, mmc_gpio_cd_irqt,
/*
* 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;
if (ret < 0)
irq = ret;
}
host->slot.cd_irq = irq;
if (irq < 0)
host->caps |= MMC_CAP_NEEDS_POLL;
ctx->cd_gpio = gpio;
host->slot.cd_irq = irq;
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;
free_irq(host->slot.cd_irq, host);
gpio_free(ctx->cd_gpio);
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);
host->slot.handler_priv = NULL;
kfree(ctx);
}
EXPORT_SYMBOL(mmc_gpio_free_cd);

2
include/linux/mmc/slot-gpio.h
View file

@ -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);