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: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c
index 468e5a0..92cba02 100644
--- a/drivers/mmc/core/slot-gpio.c
+++ b/drivers/mmc/core/slot-gpio.c
@@ -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 @@
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 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 @@
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 @@
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);
diff --git a/include/linux/mmc/slot-gpio.h b/include/linux/mmc/slot-gpio.h
index edfaa32..1a977d7 100644
--- a/include/linux/mmc/slot-gpio.h
+++ b/include/linux/mmc/slot-gpio.h
@@ -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);