video: backlight: Add devres versions of of_find_backlight

Add devm_of_find_backlight and the corresponding release
function because some drivers use devres versions of functions
for acquiring device resources.

Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Meghana Madhyastha <meghana.madhyastha@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/021f8fecfa3f374dc5dcb70fb07a6f6b019bea7b.1516810725.git.meghana.madhyastha@gmail.com

diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 553bf5c4807c9ef7d1c65894e177238229387720..deb824bef6e21015c83d4e846f130e5ff13f59e0 100644 (file)
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -623,6 +623,36 @@ struct backlight_device *of_find_backlight(struct device *dev)
 }
 EXPORT_SYMBOL(of_find_backlight);
 
+static void devm_backlight_release(void *data)
+{
+       backlight_put(data);
+}
+
+/**
+ * devm_of_find_backlight - Resource-managed of_find_backlight()
+ * @dev: Device
+ *
+ * Device managed version of of_find_backlight().
+ * The reference on the backlight device is automatically
+ * dropped on driver detach.
+ */
+struct backlight_device *devm_of_find_backlight(struct device *dev)
+{
+       struct backlight_device *bd;
+       int ret;
+
+       bd = of_find_backlight(dev);
+       if (IS_ERR_OR_NULL(bd))
+               return bd;
+       ret = devm_add_action(dev, devm_backlight_release, bd);
+       if (ret) {
+               backlight_put(bd);
+               return ERR_PTR(ret);
+       }
+       return bd;
+}
+EXPORT_SYMBOL(devm_of_find_backlight);
+
 static void __exit backlight_class_exit(void)
 {
        class_destroy(backlight_class);

diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index ddc9bade4fb2905bd063725f77fd7cad88b893f7..2baab6f3861d20ec998266dd0d36e30b3f446262 100644 (file)
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -217,11 +217,18 @@ of_find_backlight_by_node(struct device_node *node)
 
 #if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
 struct backlight_device *of_find_backlight(struct device *dev);
+struct backlight_device *devm_of_find_backlight(struct device *dev);
 #else
 static inline struct backlight_device *of_find_backlight(struct device *dev)
 {
        return NULL;
 }
+
+static inline struct backlight_device *
+devm_of_find_backlight(struct device *dev)
+{
+       return NULL;
+}
 #endif
 
 #endif