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         /* Get the backlight power status (0: full on, 1..3: power saving
  23            modes; 4: full off), see FB_BLANK_XXX */
  24         int (*get_power)(struct backlight_device *);
  25         /* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
  26         int (*set_power)(struct backlight_device *, int power);
  27         /* Maximal value for brightness (read-only) */
  28         int max_brightness;
  29         /* Get current backlight brightness */
  30         int (*get_brightness)(struct backlight_device *);
  31         /* Set backlight brightness (0..max_brightness) */
  32         int (*set_brightness)(struct backlight_device *, int brightness);
  33         /* Check if given framebuffer device is the one bound to this backlight;
  34            return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
  35         int (*check_fb)(struct fb_info *);
  36 };
  37
  38 struct backlight_device {
  39         /* This protects the 'props' field. If 'props' is NULL, the driver that
  40            registered this device has been unloaded, and if class_get_devdata()
  41            points to something in the body of that driver, it is also invalid. */
  42         struct semaphore sem;
  43         /* If this is NULL, the backing module is unloaded */
  44         struct backlight_properties *props;
  45         /* The framebuffer notifier block */
  46         struct notifier_block fb_notif;
  47         /* The class device structure */
  48         struct class_device class_dev;
  49 };
  50
  51 extern struct backlight_device *backlight_device_register(const char *name,
  52         void *devdata, struct backlight_properties *bp);
  53 extern void backlight_device_unregister(struct backlight_device *bd);
  54
  55 #define to_backlight_device(obj) container_of(obj, struct backlight_device, class_dev)
  56
  57 #endif