diff options
| author | Meghana Madhyastha <meghana.madhyastha@gmail.com> | 2018-01-24 16:35:30 +0000 |
|---|---|---|
| committer | Sean Paul <seanpaul@chromium.org> | 2018-01-29 10:34:53 -0500 |
| commit | c2adda27d202fa8f70a5d6e8b0c12b449c8868b8 (patch) | |
| tree | 4dae2ef4d28ae0b0e73022cae120a78d174f3aca | |
| parent | 5b698be0497d8be986e2050e9b1c145b2e0603c2 (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
| -rw-r--r-- | drivers/video/backlight/backlight.c | 43 | ||||
| -rw-r--r-- | include/linux/backlight.h | 19 |
2 files changed, 62 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); diff --git a/include/linux/backlight.h b/include/linux/backlight.h index ace825e2ca2d..ddc9bade4fb2 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -162,6 +162,16 @@ static inline int backlight_disable(struct backlight_device *bd) return backlight_update_status(bd); } +/** + * backlight_put - Drop backlight reference + * @bd: the backlight device to put + */ +static inline void backlight_put(struct backlight_device *bd) +{ + if (bd) + put_device(&bd->dev); +} + extern struct backlight_device *backlight_device_register(const char *name, struct device *dev, void *devdata, const struct backlight_ops *ops, const struct backlight_properties *props); @@ -205,4 +215,13 @@ of_find_backlight_by_node(struct device_node *node) } #endif +#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE) +struct backlight_device *of_find_backlight(struct device *dev); +#else +static inline struct backlight_device *of_find_backlight(struct device *dev) +{ + return NULL; +} +#endif + #endif |