From: Meghana Madhyastha <meghana.madhyastha@gmail.com>
Date: Wed, 24 Jan 2018 16:34:07 +0000
Subject: video: backlight: Add helpers to enable and disable backlight
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Git-commit: 5b698be0497d8be986e2050e9b1c145b2e0603c2
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Add helper functions backlight_enable and backlight_disable to
enable/disable a backlight device. These helper functions can
then be used by different drm and tinydrm drivers to avoid
repetition of code and also to enforce a uniform and consistent
way to enable/disable a backlight device.

Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Meghana Madhyastha <meghana.madhyastha@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/39b5bf0a02008a8072d910bdf8231c431e9ef504.1516810725.git.meghana.madhyastha@gmail.com

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 include/linux/backlight.h |   32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -129,6 +129,38 @@ static inline int backlight_update_statu
 	return ret;
 }
 
+/**
+ * backlight_enable - Enable backlight
+ * @bd: the backlight device to enable
+ */
+static inline int backlight_enable(struct backlight_device *bd)
+{
+	if (!bd)
+		return 0;
+
+	bd->props.power = FB_BLANK_UNBLANK;
+	bd->props.fb_blank = FB_BLANK_UNBLANK;
+	bd->props.state &= ~BL_CORE_FBBLANK;
+
+	return backlight_update_status(bd);
+}
+
+/**
+ * backlight_disable - Disable backlight
+ * @bd: the backlight device to disable
+ */
+static inline int backlight_disable(struct backlight_device *bd)
+{
+	if (!bd)
+		return 0;
+
+	bd->props.power = FB_BLANK_POWERDOWN;
+	bd->props.fb_blank = FB_BLANK_POWERDOWN;
+	bd->props.state |= BL_CORE_FBBLANK;
+
+	return backlight_update_status(bd);
+}
+
 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);