--- zzzz-none-000/linux-3.10.107/include/linux/backlight.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/linux/backlight.h	2021-02-04 17:41:59.000000000 +0000
@@ -9,6 +9,7 @@
 #define _LINUX_BACKLIGHT_H
 
 #include <linux/device.h>
+#include <linux/fb.h>
 #include <linux/mutex.h>
 #include <linux/notifier.h>
 
@@ -39,6 +40,11 @@
 	BACKLIGHT_TYPE_MAX,
 };
 
+enum backlight_notification {
+	BACKLIGHT_REGISTERED,
+	BACKLIGHT_UNREGISTERED,
+};
+
 struct backlight_device;
 struct fb_info;
 
@@ -100,23 +106,44 @@
 	/* The framebuffer notifier block */
 	struct notifier_block fb_notif;
 
+	/* list entry of all registered backlight devices */
+	struct list_head entry;
+
 	struct device dev;
+
+	/* Multiple framebuffers may share one backlight device */
+	bool fb_bl_on[FB_MAX];
+
+	int use_count;
 };
 
-static inline void backlight_update_status(struct backlight_device *bd)
+static inline int backlight_update_status(struct backlight_device *bd)
 {
+	int ret = -ENOENT;
+
 	mutex_lock(&bd->update_lock);
 	if (bd->ops && bd->ops->update_status)
-		bd->ops->update_status(bd);
+		ret = bd->ops->update_status(bd);
 	mutex_unlock(&bd->update_lock);
+
+	return ret;
 }
 
 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);
+extern struct backlight_device *devm_backlight_device_register(
+	struct device *dev, const char *name, struct device *parent,
+	void *devdata, const struct backlight_ops *ops,
+	const struct backlight_properties *props);
 extern void backlight_device_unregister(struct backlight_device *bd);
+extern void devm_backlight_device_unregister(struct device *dev,
+					struct backlight_device *bd);
 extern void backlight_force_update(struct backlight_device *bd,
 				   enum backlight_update_reason reason);
+extern bool backlight_device_registered(enum backlight_type type);
+extern int backlight_register_notifier(struct notifier_block *nb);
+extern int backlight_unregister_notifier(struct notifier_block *nb);
 
 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)