--- zzzz-none-000/linux-3.10.107/drivers/video/backlight/backlight.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/video/backlight/backlight.c	2021-02-04 17:41:59.000000000 +0000
@@ -21,6 +21,10 @@
 #include <asm/backlight.h>
 #endif
 
+static struct list_head backlight_dev_list;
+static struct mutex backlight_dev_list_mutex;
+static struct blocking_notifier_head backlight_notifier;
+
 static const char *const backlight_types[] = {
 	[BACKLIGHT_RAW] = "raw",
 	[BACKLIGHT_PLATFORM] = "platform",
@@ -31,13 +35,15 @@
 			   defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
 /* This callback gets called when something important happens inside a
  * framebuffer driver. We're looking if that important event is blanking,
- * and if it is, we're switching backlight power as well ...
+ * and if it is and necessary, we're switching backlight power as well ...
  */
 static int fb_notifier_callback(struct notifier_block *self,
 				unsigned long event, void *data)
 {
 	struct backlight_device *bd;
 	struct fb_event *evdata = data;
+	int node = evdata->info->node;
+	int fb_blank = 0;
 
 	/* If we aren't interested in this event, skip it immediately ... */
 	if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
@@ -48,12 +54,24 @@
 	if (bd->ops)
 		if (!bd->ops->check_fb ||
 		    bd->ops->check_fb(bd, evdata->info)) {
-			bd->props.fb_blank = *(int *)evdata->data;
-			if (bd->props.fb_blank == FB_BLANK_UNBLANK)
-				bd->props.state &= ~BL_CORE_FBBLANK;
-			else
-				bd->props.state |= BL_CORE_FBBLANK;
-			backlight_update_status(bd);
+			fb_blank = *(int *)evdata->data;
+			if (fb_blank == FB_BLANK_UNBLANK &&
+			    !bd->fb_bl_on[node]) {
+				bd->fb_bl_on[node] = true;
+				if (!bd->use_count++) {
+					bd->props.state &= ~BL_CORE_FBBLANK;
+					bd->props.fb_blank = FB_BLANK_UNBLANK;
+					backlight_update_status(bd);
+				}
+			} else if (fb_blank != FB_BLANK_UNBLANK &&
+				   bd->fb_bl_on[node]) {
+				bd->fb_bl_on[node] = false;
+				if (!(--bd->use_count)) {
+					bd->props.state |= BL_CORE_FBBLANK;
+					bd->props.fb_blank = fb_blank;
+					backlight_update_status(bd);
+				}
+			}
 		}
 	mutex_unlock(&bd->ops_lock);
 	return 0;
@@ -103,16 +121,16 @@
 	sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
 }
 
-static ssize_t backlight_show_power(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static ssize_t bl_power_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
 {
 	struct backlight_device *bd = to_backlight_device(dev);
 
 	return sprintf(buf, "%d\n", bd->props.power);
 }
 
-static ssize_t backlight_store_power(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t count)
+static ssize_t bl_power_store(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
 {
 	int rc;
 	struct backlight_device *bd = to_backlight_device(dev);
@@ -136,8 +154,9 @@
 
 	return rc;
 }
+static DEVICE_ATTR_RW(bl_power);
 
-static ssize_t backlight_show_brightness(struct device *dev,
+static ssize_t brightness_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct backlight_device *bd = to_backlight_device(dev);
@@ -145,7 +164,7 @@
 	return sprintf(buf, "%d\n", bd->props.brightness);
 }
 
-static ssize_t backlight_store_brightness(struct device *dev,
+static ssize_t brightness_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	int rc;
@@ -175,24 +194,27 @@
 
 	return rc;
 }
+static DEVICE_ATTR_RW(brightness);
 
-static ssize_t backlight_show_type(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static ssize_t type_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
 {
 	struct backlight_device *bd = to_backlight_device(dev);
 
 	return sprintf(buf, "%s\n", backlight_types[bd->props.type]);
 }
+static DEVICE_ATTR_RO(type);
 
-static ssize_t backlight_show_max_brightness(struct device *dev,
+static ssize_t max_brightness_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct backlight_device *bd = to_backlight_device(dev);
 
 	return sprintf(buf, "%d\n", bd->props.max_brightness);
 }
+static DEVICE_ATTR_RO(max_brightness);
 
-static ssize_t backlight_show_actual_brightness(struct device *dev,
+static ssize_t actual_brightness_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	int rc = -ENXIO;
@@ -201,14 +223,18 @@
 	mutex_lock(&bd->ops_lock);
 	if (bd->ops && bd->ops->get_brightness)
 		rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
+	else
+		rc = sprintf(buf, "%d\n", bd->props.brightness);
 	mutex_unlock(&bd->ops_lock);
 
 	return rc;
 }
+static DEVICE_ATTR_RO(actual_brightness);
 
 static struct class *backlight_class;
 
-static int backlight_suspend(struct device *dev, pm_message_t state)
+#ifdef CONFIG_PM_SLEEP
+static int backlight_suspend(struct device *dev)
 {
 	struct backlight_device *bd = to_backlight_device(dev);
 
@@ -235,6 +261,10 @@
 
 	return 0;
 }
+#endif
+
+static SIMPLE_DEV_PM_OPS(backlight_class_dev_pm_ops, backlight_suspend,
+			 backlight_resume);
 
 static void bl_device_release(struct device *dev)
 {
@@ -242,16 +272,15 @@
 	kfree(bd);
 }
 
-static struct device_attribute bl_device_attributes[] = {
-	__ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),
-	__ATTR(brightness, 0644, backlight_show_brightness,
-		     backlight_store_brightness),
-	__ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
-		     NULL),
-	__ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
-	__ATTR(type, 0444, backlight_show_type, NULL),
-	__ATTR_NULL,
+static struct attribute *bl_device_attrs[] = {
+	&dev_attr_bl_power.attr,
+	&dev_attr_brightness.attr,
+	&dev_attr_actual_brightness.attr,
+	&dev_attr_max_brightness.attr,
+	&dev_attr_type.attr,
+	NULL,
 };
+ATTRIBUTE_GROUPS(bl_device);
 
 /**
  * backlight_force_update - tell the backlight subsystem that hardware state
@@ -304,7 +333,7 @@
 	new_bd->dev.class = backlight_class;
 	new_bd->dev.parent = parent;
 	new_bd->dev.release = bl_device_release;
-	dev_set_name(&new_bd->dev, name);
+	dev_set_name(&new_bd->dev, "%s", name);
 	dev_set_drvdata(&new_bd->dev, devdata);
 
 	/* Set default properties */
@@ -321,7 +350,7 @@
 
 	rc = device_register(&new_bd->dev);
 	if (rc) {
-		kfree(new_bd);
+		put_device(&new_bd->dev);
 		return ERR_PTR(rc);
 	}
 
@@ -340,10 +369,35 @@
 	mutex_unlock(&pmac_backlight_mutex);
 #endif
 
+	mutex_lock(&backlight_dev_list_mutex);
+	list_add(&new_bd->entry, &backlight_dev_list);
+	mutex_unlock(&backlight_dev_list_mutex);
+
+	blocking_notifier_call_chain(&backlight_notifier,
+				     BACKLIGHT_REGISTERED, new_bd);
+
 	return new_bd;
 }
 EXPORT_SYMBOL(backlight_device_register);
 
+bool backlight_device_registered(enum backlight_type type)
+{
+	bool found = false;
+	struct backlight_device *bd;
+
+	mutex_lock(&backlight_dev_list_mutex);
+	list_for_each_entry(bd, &backlight_dev_list, entry) {
+		if (bd->props.type == type) {
+			found = true;
+			break;
+		}
+	}
+	mutex_unlock(&backlight_dev_list_mutex);
+
+	return found;
+}
+EXPORT_SYMBOL(backlight_device_registered);
+
 /**
  * backlight_device_unregister - unregisters a backlight device object.
  * @bd: the backlight device object to be unregistered and freed.
@@ -355,12 +409,20 @@
 	if (!bd)
 		return;
 
+	mutex_lock(&backlight_dev_list_mutex);
+	list_del(&bd->entry);
+	mutex_unlock(&backlight_dev_list_mutex);
+
 #ifdef CONFIG_PMAC_BACKLIGHT
 	mutex_lock(&pmac_backlight_mutex);
 	if (pmac_backlight == bd)
 		pmac_backlight = NULL;
 	mutex_unlock(&pmac_backlight_mutex);
 #endif
+
+	blocking_notifier_call_chain(&backlight_notifier,
+				     BACKLIGHT_UNREGISTERED, bd);
+
 	mutex_lock(&bd->ops_lock);
 	bd->ops = NULL;
 	mutex_unlock(&bd->ops_lock);
@@ -370,6 +432,111 @@
 }
 EXPORT_SYMBOL(backlight_device_unregister);
 
+static void devm_backlight_device_release(struct device *dev, void *res)
+{
+	struct backlight_device *backlight = *(struct backlight_device **)res;
+
+	backlight_device_unregister(backlight);
+}
+
+static int devm_backlight_device_match(struct device *dev, void *res,
+					void *data)
+{
+	struct backlight_device **r = res;
+
+	return *r == data;
+}
+
+/**
+ * backlight_register_notifier - get notified of backlight (un)registration
+ * @nb: notifier block with the notifier to call on backlight (un)registration
+ *
+ * @return 0 on success, otherwise a negative error code
+ *
+ * Register a notifier to get notified when backlight devices get registered
+ * or unregistered.
+ */
+int backlight_register_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&backlight_notifier, nb);
+}
+EXPORT_SYMBOL(backlight_register_notifier);
+
+/**
+ * backlight_unregister_notifier - unregister a backlight notifier
+ * @nb: notifier block to unregister
+ *
+ * @return 0 on success, otherwise a negative error code
+ *
+ * Register a notifier to get notified when backlight devices get registered
+ * or unregistered.
+ */
+int backlight_unregister_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&backlight_notifier, nb);
+}
+EXPORT_SYMBOL(backlight_unregister_notifier);
+
+/**
+ * devm_backlight_device_register - resource managed backlight_device_register()
+ * @dev: the device to register
+ * @name: the name of the device
+ * @parent: a pointer to the parent device
+ * @devdata: an optional pointer to be stored for private driver use
+ * @ops: the backlight operations structure
+ * @props: the backlight properties
+ *
+ * @return a struct backlight on success, or an ERR_PTR on error
+ *
+ * Managed backlight_device_register(). The backlight_device returned
+ * from this function are automatically freed on driver detach.
+ * See backlight_device_register() for more information.
+ */
+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)
+{
+	struct backlight_device **ptr, *backlight;
+
+	ptr = devres_alloc(devm_backlight_device_release, sizeof(*ptr),
+			GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	backlight = backlight_device_register(name, parent, devdata, ops,
+						props);
+	if (!IS_ERR(backlight)) {
+		*ptr = backlight;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return backlight;
+}
+EXPORT_SYMBOL(devm_backlight_device_register);
+
+/**
+ * devm_backlight_device_unregister - resource managed backlight_device_unregister()
+ * @dev: the device to unregister
+ * @bd: the backlight device to unregister
+ *
+ * Deallocated a backlight allocated with devm_backlight_device_register().
+ * Normally this function will not need to be called and the resource management
+ * code will ensure that the resource is freed.
+ */
+void devm_backlight_device_unregister(struct device *dev,
+				struct backlight_device *bd)
+{
+	int rc;
+
+	rc = devres_release(dev, devm_backlight_device_release,
+				devm_backlight_device_match, bd);
+	WARN_ON(rc);
+}
+EXPORT_SYMBOL(devm_backlight_device_unregister);
+
 #ifdef CONFIG_OF
 static int of_parent_match(struct device *dev, const void *data)
 {
@@ -413,9 +580,12 @@
 		return PTR_ERR(backlight_class);
 	}
 
-	backlight_class->dev_attrs = bl_device_attributes;
-	backlight_class->suspend = backlight_suspend;
-	backlight_class->resume = backlight_resume;
+	backlight_class->dev_groups = bl_device_groups;
+	backlight_class->pm = &backlight_class_dev_pm_ops;
+	INIT_LIST_HEAD(&backlight_dev_list);
+	mutex_init(&backlight_dev_list_mutex);
+	BLOCKING_INIT_NOTIFIER_HEAD(&backlight_notifier);
+
 	return 0;
 }