[PATCH v14 3/3] drm/tinydrm: Add devres versions of of_find_backlight

[Meghana Madhyastha]

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

Signed-off-by: Meghana Madhyastha <meghana.madhyas...@gmail.com>
---
Changes in v14:
 - s/devm_backlight_get/devm_of_find_backlight/
 - change commit message from requiring to acquiring

 drivers/gpu/drm/tinydrm/mi0283qt.c  |  2 +-
 drivers/video/backlight/backlight.c | 31 +++++++++++++++++++++++++++++++
 include/linux/backlight.h           |  7 +++++++
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c 
b/drivers/gpu/drm/tinydrm/mi0283qt.c
index 53ab5a0..568834a 100644
--- a/drivers/gpu/drm/tinydrm/mi0283qt.c
+++ b/drivers/gpu/drm/tinydrm/mi0283qt.c
@@ -189,7 +189,7 @@ static int mi0283qt_probe(struct spi_device *spi)
        if (IS_ERR(mipi->regulator))
                return PTR_ERR(mipi->regulator);
 
-       mipi->backlight = of_find_backlight(dev);
+       mipi->backlight = devm_of_find_backlight(dev);
        if (IS_ERR(mipi->backlight))
                return PTR_ERR(mipi->backlight);
 
diff --git a/drivers/video/backlight/backlight.c 
b/drivers/video/backlight/backlight.c
index 76d46c3..4bb7bf3 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -617,6 +617,37 @@ struct backlight_device *of_find_backlight(struct device 
*dev)
 }
 EXPORT_SYMBOL(of_find_backlight);
 
+static void devm_backlight_put(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 (!bd)
+               return NULL;
+
+       ret = devm_add_action(dev, devm_backlight_put, 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 f98b684..a52bda0 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -214,11 +214,18 @@ 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
-- 
2.7.4

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