v4.19.13 snapshot.
diff --git a/include/linux/backlight.h b/include/linux/backlight.h
new file mode 100644
index 0000000..0b58974
--- /dev/null
+++ b/include/linux/backlight.h
@@ -0,0 +1,229 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Backlight Lowlevel Control Abstraction
+ *
+ * Copyright (C) 2003,2004 Hewlett-Packard Company
+ *
+ */
+
+#ifndef _LINUX_BACKLIGHT_H
+#define _LINUX_BACKLIGHT_H
+
+#include <linux/device.h>
+#include <linux/fb.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+
+/* Notes on locking:
+ *
+ * backlight_device->ops_lock is an internal backlight lock protecting the
+ * ops pointer and no code outside the core should need to touch it.
+ *
+ * Access to update_status() is serialised by the update_lock mutex since
+ * most drivers seem to need this and historically get it wrong.
+ *
+ * Most drivers don't need locking on their get_brightness() method.
+ * If yours does, you need to implement it in the driver. You can use the
+ * update_lock mutex if appropriate.
+ *
+ * Any other use of the locks below is probably wrong.
+ */
+
+enum backlight_update_reason {
+ BACKLIGHT_UPDATE_HOTKEY,
+ BACKLIGHT_UPDATE_SYSFS,
+};
+
+enum backlight_type {
+ BACKLIGHT_RAW = 1,
+ BACKLIGHT_PLATFORM,
+ BACKLIGHT_FIRMWARE,
+ BACKLIGHT_TYPE_MAX,
+};
+
+enum backlight_notification {
+ BACKLIGHT_REGISTERED,
+ BACKLIGHT_UNREGISTERED,
+};
+
+struct backlight_device;
+struct fb_info;
+
+struct backlight_ops {
+ unsigned int options;
+
+#define BL_CORE_SUSPENDRESUME (1 << 0)
+
+ /* Notify the backlight driver some property has changed */
+ int (*update_status)(struct backlight_device *);
+ /* Return the current backlight brightness (accounting for power,
+ fb_blank etc.) */
+ int (*get_brightness)(struct backlight_device *);
+ /* Check if given framebuffer device is the one bound to this backlight;
+ return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
+ int (*check_fb)(struct backlight_device *, struct fb_info *);
+};
+
+/* This structure defines all the properties of a backlight */
+struct backlight_properties {
+ /* Current User requested brightness (0 - max_brightness) */
+ int brightness;
+ /* Maximal value for brightness (read-only) */
+ int max_brightness;
+ /* Current FB Power mode (0: full on, 1..3: power saving
+ modes; 4: full off), see FB_BLANK_XXX */
+ int power;
+ /* FB Blanking active? (values as for power) */
+ /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
+ int fb_blank;
+ /* Backlight type */
+ enum backlight_type type;
+ /* Flags used to signal drivers of state changes */
+ unsigned int state;
+
+#define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
+#define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
+
+};
+
+struct backlight_device {
+ /* Backlight properties */
+ struct backlight_properties props;
+
+ /* Serialise access to update_status method */
+ struct mutex update_lock;
+
+ /* This protects the 'ops' field. If 'ops' is NULL, the driver that
+ registered this device has been unloaded, and if class_get_devdata()
+ points to something in the body of that driver, it is also invalid. */
+ struct mutex ops_lock;
+ const struct backlight_ops *ops;
+
+ /* 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 int backlight_update_status(struct backlight_device *bd)
+{
+ int ret = -ENOENT;
+
+ mutex_lock(&bd->update_lock);
+ if (bd->ops && bd->ops->update_status)
+ ret = bd->ops->update_status(bd);
+ mutex_unlock(&bd->update_lock);
+
+ 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);
+}
+
+/**
+ * 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);
+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 int backlight_register_notifier(struct notifier_block *nb);
+extern int backlight_unregister_notifier(struct notifier_block *nb);
+extern struct backlight_device *backlight_device_get_by_type(enum backlight_type type);
+extern int backlight_device_set_brightness(struct backlight_device *bd, unsigned long brightness);
+
+#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
+
+static inline void * bl_get_data(struct backlight_device *bl_dev)
+{
+ return dev_get_drvdata(&bl_dev->dev);
+}
+
+struct generic_bl_info {
+ const char *name;
+ int max_intensity;
+ int default_intensity;
+ int limit_mask;
+ void (*set_bl_intensity)(int intensity);
+ void (*kick_battery)(void);
+};
+
+#ifdef CONFIG_OF
+struct backlight_device *of_find_backlight_by_node(struct device_node *node);
+#else
+static inline struct backlight_device *
+of_find_backlight_by_node(struct device_node *node)
+{
+ return NULL;
+}
+#endif
+
+#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+struct backlight_device *of_find_backlight(struct device *dev);
+struct backlight_device *devm_of_find_backlight(struct device *dev);
+#else
+static inline struct backlight_device *of_find_backlight(struct device *dev)
+{
+ return NULL;
+}
+
+static inline struct backlight_device *
+devm_of_find_backlight(struct device *dev)
+{
+ return NULL;
+}
+#endif
+
+#endif