LXR linux/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/mutex.h>
  13#include <linux/notifier.h>
  14
  15/* Notes on locking:
  16 *
  17 * backlight_device->ops_lock is an internal backlight lock protecting the
  18 * ops pointer and no code outside the core should need to touch it.
  19 *
  20 * Access to update_status() is serialised by the update_lock mutex since
  21 * most drivers seem to need this and historically get it wrong.
  22 *
  23 * Most drivers don't need locking on their get_brightness() method.
  24 * If yours does, you need to implement it in the driver. You can use the
  25 * update_lock mutex if appropriate.
  26 *
  27 * Any other use of the locks below is probably wrong.
  28 */
  29
  30struct backlight_device;
  31struct fb_info;
  32
  33struct backlight_ops {
  34        /* Notify the backlight driver some property has changed */
  35        int (*update_status)(struct backlight_device *);
  36        /* Return the current backlight brightness (accounting for power,
  37           fb_blank etc.) */
  38        int (*get_brightness)(struct backlight_device *);
  39        /* Check if given framebuffer device is the one bound to this backlight;
  40           return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
  41        int (*check_fb)(struct fb_info *);
  42};
  43
  44/* This structure defines all the properties of a backlight */
  45struct backlight_properties {
  46        /* Current User requested brightness (0 - max_brightness) */
  47        int brightness;
  48        /* Maximal value for brightness (read-only) */
  49        int max_brightness;
  50        /* Current FB Power mode (0: full on, 1..3: power saving
  51           modes; 4: full off), see FB_BLANK_XXX */
  52        int power;
  53        /* FB Blanking active? (values as for power) */
  54        int fb_blank;
  55};
  56
  57struct backlight_device {
  58        /* Backlight properties */
  59        struct backlight_properties props;
  60
  61        /* Serialise access to update_status method */
  62        struct mutex update_lock;
  63
  64        /* This protects the 'ops' field. If 'ops' is NULL, the driver that
  65           registered this device has been unloaded, and if class_get_devdata()
  66           points to something in the body of that driver, it is also invalid. */
  67        struct mutex ops_lock;
  68        struct backlight_ops *ops;
  69
  70        /* The framebuffer notifier block */
  71        struct notifier_block fb_notif;
  72
  73        struct device dev;
  74};
  75
  76static inline void backlight_update_status(struct backlight_device *bd)
  77{
  78        mutex_lock(&bd->update_lock);
  79        if (bd->ops && bd->ops->update_status)
  80                bd->ops->update_status(bd);
  81        mutex_unlock(&bd->update_lock);
  82}
  83
  84extern struct backlight_device *backlight_device_register(const char *name,
  85        struct device *dev, void *devdata, struct backlight_ops *ops);
  86extern void backlight_device_unregister(struct backlight_device *bd);
  87
  88#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
  89
  90static inline void * bl_get_data(struct backlight_device *bl_dev)
  91{
  92        return dev_get_drvdata(&bl_dev->dev);
  93}
  94
  95struct generic_bl_info {
  96        const char *name;
  97        int max_intensity;
  98        int default_intensity;
  99        int limit_mask;
 100        void (*set_bl_intensity)(int intensity);
 101        void (*kick_battery)(void);
 102};
 103
 104#endif
 105