From c2adda27d202fa8f70a5d6e8b0c12b449c8868b8 Mon Sep 17 00:00:00 2001 From: Meghana Madhyastha Date: Wed, 24 Jan 2018 16:35:30 +0000 Subject: 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 Reviewed-by: Noralf Trønnes Reviewed-by: Sean Paul Reviewed-by: Thierry Reding Signed-off-by: Meghana Madhyastha Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/116d160ba78be2e6dcbdcb6855622bce67da9472.1516810725.git.meghana.madhyastha@gmail.com --- drivers/video/backlight/backlight.c | 43 +++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'drivers/video/backlight') 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); -- cgit v1.2.3-55-g7522