A power gpio is a sideband output gpio that controls card power.
Signed-off-by: Chris Ball <c...@laptop.org>
---
Hi Guennadi, what do you think of this patch? I'm hoping to use it
first to de-duplicate power-gpio handling between sdhci-pxa and
sdhci-tegra, and then to create a generic DT parser for MMC.
The zero-length array trick might be becoming unmaintainable as we add
more labels to the struct like this. Do you think we should keep it
as-is, or change to individual allocations? Thanks!
drivers/mmc/core/slot-gpio.c | 65 ++++++++++++++++++++++++++++++++++++++++++-
include/linux/mmc/host.h | 1 +
include/linux/mmc/slot-gpio.h | 3 ++
3 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c
index 4f9b366..6c785dd 100644
--- a/drivers/mmc/core/slot-gpio.c
+++ b/drivers/mmc/core/slot-gpio.c
@@ -20,6 +20,8 @@
struct mmc_gpio {
int ro_gpio;
int cd_gpio;
+ int pwr_gpio;
+ char *pwr_label;
char *ro_label;
char cd_label[0];
};
@@ -33,6 +35,9 @@ static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
static int mmc_gpio_alloc(struct mmc_host *host)
{
+ /* The "+ 4" is to leave room for a space, two-char identifier
+ * and \0 after each label in the mmc_gpio struct.
+ */
size_t len = strlen(dev_name(host->parent)) + 4;
struct mmc_gpio *ctx;
@@ -45,14 +50,19 @@ static int mmc_gpio_alloc(struct mmc_host *host)
* before device_add(), i.e., between mmc_alloc_host() and
* mmc_add_host()
*/
- ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len,
+
+ /* len*3 because we have three strings to allocate on the end.
*/
+ ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + len*3,
GFP_KERNEL);
if (ctx) {
ctx->ro_label = ctx->cd_label + len;
+ ctx->pwr_label = ctx->cd_label + len*2;
snprintf(ctx->cd_label, len, "%s cd",
dev_name(host->parent));
snprintf(ctx->ro_label, len, "%s ro",
dev_name(host->parent));
+ snprintf(ctx->pwr_label, len, "%s pw",
dev_name(host->parent));
ctx->cd_gpio = -EINVAL;
ctx->ro_gpio = -EINVAL;
+ ctx->pwr_gpio = -EINVAL;
host->slot.handler_priv = ctx;
}
}
@@ -74,6 +84,18 @@ int mmc_gpio_get_ro(struct mmc_host *host)
}
EXPORT_SYMBOL(mmc_gpio_get_ro);
+int mmc_gpio_get_pwr(struct mmc_host *host)
+{
+ struct mmc_gpio *ctx = host->slot.handler_priv;
+
+ if (!ctx || !gpio_is_valid(ctx->pwr_gpio))
+ return -ENOSYS;
+
+ return !gpio_get_value_cansleep(ctx->pwr_gpio) ^
+ !!(host->caps2 & MMC_CAP2_PWR_ACTIVE_HIGH);
+}
+EXPORT_SYMBOL(mmc_gpio_get_pwr);
+
int mmc_gpio_get_cd(struct mmc_host *host)
{
struct mmc_gpio *ctx = host->slot.handler_priv;
@@ -105,6 +127,32 @@ int mmc_gpio_request_ro(struct mmc_host *host, unsigned
int gpio)
}
EXPORT_SYMBOL(mmc_gpio_request_ro);
+int mmc_gpio_request_pwr(struct mmc_host *host, unsigned int gpio)
+{
+ struct mmc_gpio *ctx;
+ int ret;
+ unsigned long gpio_flags;
+
+ if (!gpio_is_valid(gpio))
+ return -EINVAL;
+
+ ret = mmc_gpio_alloc(host);
+ if (ret < 0)
+ return ret;
+
+ ctx = host->slot.handler_priv;
+ ctx->pwr_gpio = gpio;
+
+ gpio_flags = GPIOF_DIR_OUT;
+ if (host->caps2 & MMC_CAP2_PWR_ACTIVE_HIGH)
+ gpio_flags |= GPIOF_INIT_HIGH;
+ else
+ gpio_flags |= GPIOF_INIT_LOW;
+
+ return gpio_request_one(gpio, gpio_flags, ctx->pwr_label);
+}
+EXPORT_SYMBOL(mmc_gpio_request_pwr);
+
int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
{
struct mmc_gpio *ctx;
@@ -168,6 +216,21 @@ void mmc_gpio_free_ro(struct mmc_host *host)
}
EXPORT_SYMBOL(mmc_gpio_free_ro);
+void mmc_gpio_free_pwr(struct mmc_host *host)
+{
+ struct mmc_gpio *ctx = host->slot.handler_priv;
+ int gpio;
+
+ if (!ctx || !gpio_is_valid(ctx->pwr_gpio))
+ return;
+
+ gpio = ctx->pwr_gpio;
+ ctx->pwr_gpio = -EINVAL;
+
+ gpio_free(gpio);
+}
+EXPORT_SYMBOL(mmc_gpio_free_pwr);
+
void mmc_gpio_free_cd(struct mmc_host *host)
{
struct mmc_gpio *ctx = host->slot.handler_priv;
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index d5d9bd4..5a00cc1 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -257,6 +257,7 @@ struct mmc_host {
#define MMC_CAP2_HC_ERASE_SZ (1 << 9) /* High-capacity erase size */
#define MMC_CAP2_CD_ACTIVE_HIGH (1 << 10) /* Card-detect signal
active high */
#define MMC_CAP2_RO_ACTIVE_HIGH (1 << 11) /* Write-protect signal
active high */
+#define MMC_CAP2_PWR_ACTIVE_HIGH (1 << 12) /* Card power signal active
high */
mmc_pm_flag_t pm_caps; /* supported pm features */
unsigned int power_notify_type;
diff --git a/include/linux/mmc/slot-gpio.h b/include/linux/mmc/slot-gpio.h
index 7d88d27..d083dfa 100644
--- a/include/linux/mmc/slot-gpio.h
+++ b/include/linux/mmc/slot-gpio.h
@@ -21,4 +21,7 @@ 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);
+int mmc_gpio_get_pwr(struct mmc_host *host);
+int mmc_gpio_request_pwr(struct mmc_host *host, unsigned int gpio);
+void mmc_gpio_free_pwr(struct mmc_host *host);
#endif
--
Chris Ball <c...@laptop.org> <http://printf.net/>
One Laptop Per Child
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