include/linux/backlight.h

   1 /*
   2  * Backlight Lowlevel Control Abstraction
   3  *
   4  * Copyright (C) 2003,2004 Hewlett-Packard Company
   5  *
   6  */
   7
   8 #ifndef _LINUX_BACKLIGHT_H
   9 #define _LINUX_BACKLIGHT_H
  10
  11 #include <linux/device.h>
  12 #include <linux/notifier.h>
  13
  14 struct backlight_device;
  15 struct fb_info;
  16
  17 /* This structure defines all the properties of a backlight
  18    (usually attached to a LCD). */
  19 struct backlight_properties {
  20         /* Owner module */
  21         struct module *owner;
  22
  23         /* Notify the backlight driver some property has changed */
  24         int (*update_status)(struct backlight_device *);
  25         /* Return the current backlight brightness (accounting for power,
  26            fb_blank etc.) */
  27         int (*get_brightness)(struct backlight_device *);
  28         /* Check if given framebuffer device is the one bound to this backlight;
  29            return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
  30         int (*check_fb)(struct fb_info *);
  31
  32         /* Current User requested brightness (0 - max_brightness) */
  33         int brightness;
  34         /* Maximal value for brightness (read-only) */
  35         int max_brightness;
  36         /* Current FB Power mode (0: full on, 1..3: power saving
  37            modes; 4: full off), see FB_BLANK_XXX */
  38         int power;
  39         /* FB Blanking active? (values as for power) */
  40         int fb_blank;
  41 };
  42
  43 struct backlight_device {
  44         /* This protects the 'props' field. If 'props' is NULL, the driver that
  45            registered this device has been unloaded, and if class_get_devdata()
  46            points to something in the body of that driver, it is also invalid. */
  47         struct semaphore sem;
  48         /* If this is NULL, the backing module is unloaded */
  49         struct backlight_properties *props;
  50         /* The framebuffer notifier block */
  51         struct notifier_block fb_notif;
  52         /* The class device structure */
  53         struct class_device class_dev;
  54 };
  55
  56 extern struct backlight_device *backlight_device_register(const char *name,
  57         void *devdata, struct backlight_properties *bp);
  58 extern void backlight_device_unregister(struct backlight_device *bd);
  59
  60 #define to_backlight_device(obj) container_of(obj, struct backlight_device, class_dev)
  61
  62 #endif