/* 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,}; enum backlight_scale {	BACKLIGHT_SCALE_UNKNOWN = 0,	BACKLIGHT_SCALE_LINEAR,	BACKLIGHT_SCALE_NON_LINEAR,}; 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;	/* Type of the brightness scale (linear, non-linear, ...) */	enum backlight_scale scale; #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_OFstruct backlight_device *of_find_backlight_by_node(struct device_node *node);#elsestatic 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);#elsestatic 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