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authorThierry Reding <thierry.reding@avionic-design.de>2012-12-17 16:01:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-17 17:15:16 -0800
commit762a936fba7bd9225ca9a96e4860f6969b6b5670 (patch)
treeafb3f60c95eb8d21573e80683c61bb43ebb58ffe /drivers/video
parentfb08cd9b111c6a922f468ef5e33acc67eb91d40b (diff)
backlight: add of_find_backlight_by_node()
This function finds the struct backlight_device for a given device tree node. A dummy function is provided so that it safely compiles out if OF support is disabled. [akpm@linux-foundation.org: Don't use IS_ENABLED(CONFIG_OF)] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Jingoo Han <jg1.han@samsung.com> Reviewed-by: Grant Likely <grant.likely@secretlab.ca> Cc: Thierry Reding <thierry.reding@avionic-design.de> Reviewed-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/backlight/backlight.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 297db2fa91f5..345f6660d4b3 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -370,6 +370,35 @@ void backlight_device_unregister(struct backlight_device *bd)
}
EXPORT_SYMBOL(backlight_device_unregister);
+#ifdef CONFIG_OF
+static int of_parent_match(struct device *dev, void *data)
+{
+ return dev->parent && dev->parent->of_node == data;
+}
+
+/**
+ * of_find_backlight_by_node() - find backlight device by device-tree node
+ * @node: device-tree node of the backlight device
+ *
+ * Returns a pointer to the backlight device corresponding to the given DT
+ * node or NULL if no such backlight device exists or if the device hasn't
+ * been probed yet.
+ *
+ * This function obtains a reference on the backlight device and it is the
+ * caller's responsibility to drop the reference by calling put_device() on
+ * the backlight device's .dev field.
+ */
+struct backlight_device *of_find_backlight_by_node(struct device_node *node)
+{
+ struct device *dev;
+
+ dev = class_find_device(backlight_class, NULL, node, of_parent_match);
+
+ return dev ? to_backlight_device(dev) : NULL;
+}
+EXPORT_SYMBOL(of_find_backlight_by_node);
+#endif
+
static void __exit backlight_class_exit(void)
{
class_destroy(backlight_class);

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