[PATCH v13 3/3] drm/tinydrm: Add devres versions of backlight_get

[Meghana Madhyastha]

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

Signed-off-by: Meghana Madhyastha <meghana.madhyas...@gmail.com>
---
Changes in v13:
 -Add devm_backlight_put to backlight.c

 drivers/gpu/drm/tinydrm/mi0283qt.c  |  2 +-
 drivers/video/backlight/backlight.c | 31 +++++++++++++++++++++++++++++++
 include/linux/backlight.h           |  6 ++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c 
b/drivers/gpu/drm/tinydrm/mi0283qt.c
index a932185..e3e7583 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 = backlight_get(dev);
+       mipi->backlight = devm_backlight_get(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 c4e94d0..b6c505a 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -617,6 +617,37 @@ struct backlight_device *backlight_get(struct device *dev)
 }
 EXPORT_SYMBOL(backlight_get);
 
+static void devm_backlight_put(void *data)
+{
+       backlight_put(data);
+}
+
+/**
+ * devm_backlight_get - Resource-managed backlight_get()
+ * @dev: Device
+ *
+ * Device managed version of backlight_get(). The reference on the backlight
+ * device is automatically dropped on driver detach.
+ */
+struct backlight_device *devm_backlight_get(struct device *dev)
+{
+       struct backlight_device *bd;
+       int ret;
+
+       bd = backlight_get(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_backlight_get);
+
 static void __exit backlight_class_exit(void)
 {
        class_destroy(backlight_class);
diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index 987a6d7..8db9ba9 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -214,11 +214,17 @@ of_find_backlight_by_node(struct device_node *node)
 
 #if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
 struct backlight_device *backlight_get(struct device *dev);
+struct backlight_device *devm_backlight_get(struct device *dev);
 #else
 static inline struct backlight_device *backlight_get(struct device *dev)
 {
        return NULL;
 }
+
+static inline struct backlight_device *devm_backlight_get(struct device *dev)
+{
+       return NULL;
+}
 #endif
 
 #endif
-- 
2.7.4

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