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        unsigned int options;
  35
  36#define BL_CORE_SUSPENDRESUME   (1 << 0)
  37
  38        /* Notify the backlight driver some property has changed */
  39        int (*update_status)(struct backlight_device *);
  40        /* Return the current backlight brightness (accounting for power,
  41           fb_blank etc.) */
  42        int (*get_brightness)(struct backlight_device *);
  43        /* Check if given framebuffer device is the one bound to this backlight;
  44           return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
  45        int (*check_fb)(struct fb_info *);
  46};
  47
  48/* This structure defines all the properties of a backlight */
  49struct backlight_properties {
  50        /* Current User requested brightness (0 - max_brightness) */
  51        int brightness;
  52        /* Maximal value for brightness (read-only) */
  53        int max_brightness;
  54        /* Current FB Power mode (0: full on, 1..3: power saving
  55           modes; 4: full off), see FB_BLANK_XXX */
  56        int power;
  57        /* FB Blanking active? (values as for power) */
  58        /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
  59        int fb_blank;
  60        /* Flags used to signal drivers of state changes */
  61        /* Upper 4 bits are reserved for driver internal use */
  62        unsigned int state;
  63
  64#define BL_CORE_SUSPENDED       (1 << 0)        /* backlight is suspended */
  65#define BL_CORE_FBBLANK         (1 << 1)        /* backlight is under an fb blank event */
  66#define BL_CORE_DRIVER4         (1 << 28)       /* reserved for driver specific use */
  67#define BL_CORE_DRIVER3         (1 << 29)       /* reserved for driver specific use */
  68#define BL_CORE_DRIVER2         (1 << 30)       /* reserved for driver specific use */
  69#define BL_CORE_DRIVER1         (1 << 31)       /* reserved for driver specific use */
  70
  71};
  72
  73struct backlight_device {
  74        /* Backlight properties */
  75        struct backlight_properties props;
  76
  77        /* Serialise access to update_status method */
  78        struct mutex update_lock;
  79
  80        /* This protects the 'ops' field. If 'ops' is NULL, the driver that
  81           registered this device has been unloaded, and if class_get_devdata()
  82           points to something in the body of that driver, it is also invalid. */
  83        struct mutex ops_lock;
  84        struct backlight_ops *ops;
  85
  86        /* The framebuffer notifier block */
  87        struct notifier_block fb_notif;
  88
  89        struct device dev;
  90};
  91
  92static inline void backlight_update_status(struct backlight_device *bd)
  93{
  94        mutex_lock(&bd->update_lock);
  95        if (bd->ops && bd->ops->update_status)
  96                bd->ops->update_status(bd);
  97        mutex_unlock(&bd->update_lock);
  98}
  99
 100extern struct backlight_device *backlight_device_register(const char *name,
 101        struct device *dev, void *devdata, struct backlight_ops *ops);
 102extern void backlight_device_unregister(struct backlight_device *bd);
 103
 104#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
 105
 106static inline void * bl_get_data(struct backlight_device *bl_dev)
 107{
 108        return dev_get_drvdata(&bl_dev->dev);
 109}
 110
 111struct generic_bl_info {
 112        const char *name;
 113        int max_intensity;
 114        int default_intensity;
 115        int limit_mask;
 116        void (*set_bl_intensity)(int intensity);
 117        void (*kick_battery)(void);
 118};
 119
 120#endif
 121