/* * 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/notifier.h> struct backlight_device;struct fb_info; /* This structure defines all the properties of a backlight   (usually attached to a LCD). */struct backlight_properties {	/* Owner module */	struct module *owner; 	/* 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 fb_info *); 	/* 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) */	int fb_blank;}; struct backlight_device {	/* This protects the 'props' field. If 'props' 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 semaphore sem;	/* If this is NULL, the backing module is unloaded */	struct backlight_properties *props;	/* The framebuffer notifier block */	struct notifier_block fb_notif;	/* The class device structure */	struct class_device class_dev;}; extern struct backlight_device *backlight_device_register(const char *name,	void *devdata, struct backlight_properties *bp);extern void backlight_device_unregister(struct backlight_device *bd); #define to_backlight_device(obj) container_of(obj, struct backlight_device, class_dev) #endif