[PATCH v19 05/10] video: backlight: Add devres versions of of_find_backlight

From: Meghana Madhyastha
Date: Wed Jan 24 2018 - 11:37:40 EST


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@xxxxxxxxxx>
Reviewed-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
Reviewed-by: Sean Paul<seanpaul@xxxxxxxxxxxx>
Signed-off-by: Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx>
---
drivers/video/backlight/backlight.c | 30 ++++++++++++++++++++++++++++++
include/linux/backlight.h | 7 +++++++
2 files changed, 37 insertions(+)

diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 553bf5c48..deb824bef 100644
--- 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 ddc9bade4..2baab6f38 100644
--- 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
--
2.11.0