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authorMeghana Madhyastha <meghana.madhyastha@gmail.com>2018-01-24 16:35:30 +0000
committerSean Paul <seanpaul@chromium.org>2018-01-29 10:34:53 -0500
commitc2adda27d202fa8f70a5d6e8b0c12b449c8868b8 (patch)
tree4dae2ef4d28ae0b0e73022cae120a78d174f3aca /drivers/video/backlight
parent5b698be0497d8be986e2050e9b1c145b2e0603c2 (diff)
video: backlight: Add of_find_backlight helper in backlight.c
Add of_find_backlight, a helper function which is a generic version of tinydrm_of_find_backlight that can be used by other drivers to avoid repetition of code and simplify things. Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Sean Paul <seanpaul@chromium.org> Reviewed-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Meghana Madhyastha <meghana.madhyastha@gmail.com> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/116d160ba78be2e6dcbdcb6855622bce67da9472.1516810725.git.meghana.madhyastha@gmail.com
Diffstat (limited to 'drivers/video/backlight')
-rw-r--r--drivers/video/backlight/backlight.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 8049e7656daa..553bf5c4807c 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -580,6 +580,49 @@ struct backlight_device *of_find_backlight_by_node(struct device_node *node)
EXPORT_SYMBOL(of_find_backlight_by_node);
#endif
+/**
+ * of_find_backlight - Get backlight device
+ * @dev: Device
+ *
+ * This function looks for a property named 'backlight' on the DT node
+ * connected to @dev and looks up the backlight device.
+ *
+ * Call backlight_put() to drop the reference on the backlight device.
+ *
+ * Returns:
+ * A pointer to the backlight device if found.
+ * Error pointer -EPROBE_DEFER if the DT property is set, but no backlight
+ * device is found.
+ * NULL if there's no backlight property.
+ */
+struct backlight_device *of_find_backlight(struct device *dev)
+{
+ struct backlight_device *bd = NULL;
+ struct device_node *np;
+
+ if (!dev)
+ return NULL;
+
+ if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
+ np = of_parse_phandle(dev->of_node, "backlight", 0);
+ if (np) {
+ bd = of_find_backlight_by_node(np);
+ of_node_put(np);
+ if (!bd)
+ return ERR_PTR(-EPROBE_DEFER);
+ /*
+ * Note: gpio_backlight uses brightness as
+ * power state during probe
+ */
+ if (!bd->props.brightness)
+ bd->props.brightness = bd->props.max_brightness;
+ }
+ }
+
+ return bd;
+}
+EXPORT_SYMBOL(of_find_backlight);
+
static void __exit backlight_class_exit(void)
{
class_destroy(backlight_class);