mmc: core: add WP pin handler to slot functions

Card Write-Protect pin is often implemented, using a GPIO, which makes
it simple to provide a generic handler for it.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 51 insertions, 1 deletions

diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c
index 41689da14b8d..058242916cef 100644
--- a/drivers/mmc/core/slot-gpio.c
+++ b/drivers/mmc/core/slot-gpio.c
@@ -18,7 +18,9 @@
 #include <linux/slab.h>
 
 struct mmc_gpio {
+        int ro_gpio;
         int cd_gpio;
+        char *ro_label;
         char cd_label[0];
 };
 
@@ -43,11 +45,14 @@ 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) + len,
+                ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len,
                                    GFP_KERNEL);
                 if (ctx) {
+                        ctx->ro_label = ctx->cd_label + len;
                         snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
+                        snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent));
                         ctx->cd_gpio = -EINVAL;
+                        ctx->ro_gpio = -EINVAL;
                         host->slot.handler_priv = ctx;
                 }
         }
@@ -57,6 +62,18 @@ static int mmc_gpio_alloc(struct mmc_host *host)
         return ctx ? 0 : -ENOMEM;
 }
 
+int mmc_gpio_get_ro(struct mmc_host *host)
+{
+        struct mmc_gpio *ctx = host->slot.handler_priv;
+
+        if (!ctx || !gpio_is_valid(ctx->ro_gpio))
+                return -ENOSYS;
+
+        return !gpio_get_value_cansleep(ctx->ro_gpio) ^
+                !!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH);
+}
+EXPORT_SYMBOL(mmc_gpio_get_ro);
+
 int mmc_gpio_get_cd(struct mmc_host *host)
 {
         struct mmc_gpio *ctx = host->slot.handler_priv;
@@ -69,6 +86,24 @@ int mmc_gpio_get_cd(struct mmc_host *host)
 }
 EXPORT_SYMBOL(mmc_gpio_get_cd);
 
+int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
+{
+        struct mmc_gpio *ctx;
+        int ret;
+
+        if (!gpio_is_valid(gpio))
+                return -EINVAL;
+
+        ret = mmc_gpio_alloc(host);
+        if (ret < 0)
+                return ret;
+
+        ctx = host->slot.handler_priv;
+
+        return gpio_request_one(gpio, GPIOF_DIR_IN, ctx->ro_label);
+}
+EXPORT_SYMBOL(mmc_gpio_request_ro);
+
 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
 {
         struct mmc_gpio *ctx;
@@ -117,6 +152,21 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
 }
 EXPORT_SYMBOL(mmc_gpio_request_cd);
 
+void mmc_gpio_free_ro(struct mmc_host *host)
+{
+        struct mmc_gpio *ctx = host->slot.handler_priv;
+        int gpio;
+
+        if (!ctx || !gpio_is_valid(ctx->ro_gpio))
+                return;
+
+        gpio = ctx->ro_gpio;
+        ctx->ro_gpio = -EINVAL;
+
+        gpio_free(gpio);
+}
+EXPORT_SYMBOL(mmc_gpio_free_ro);
+
 void mmc_gpio_free_cd(struct mmc_host *host)
 {
         struct mmc_gpio *ctx = host->slot.handler_priv;