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
  30enum backlight_update_reason {
  31        BACKLIGHT_UPDATE_HOTKEY,
  32        BACKLIGHT_UPDATE_SYSFS,
  33};
  34
  35struct backlight_device;
  36struct fb_info;
  37
  38struct backlight_ops {
  39        unsigned int options;
  40
  41#define BL_CORE_SUSPENDRESUME   (1 << 0)
  42
  43        /* Notify the backlight driver some property has changed */
  44        int (*update_status)(struct backlight_device *);
  45        /* Return the current backlight brightness (accounting for power,
  46           fb_blank etc.) */
  47        int (*get_brightness)(struct backlight_device *);
  48        /* Check if given framebuffer device is the one bound to this backlight;
  49           return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
  50        int (*check_fb)(struct backlight_device *, struct fb_info *);
  51};
  52
  53/* This structure defines all the properties of a backlight */
  54struct backlight_properties {
  55        /* Current User requested brightness (0 - max_brightness) */
  56        int brightness;
  57        /* Maximal value for brightness (read-only) */
  58        int max_brightness;
  59        /* Current FB Power mode (0: full on, 1..3: power saving
  60           modes; 4: full off), see FB_BLANK_XXX */
  61        int power;
  62        /* FB Blanking active? (values as for power) */
  63        /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
  64        int fb_blank;
  65        /* Flags used to signal drivers of state changes */
  66        /* Upper 4 bits are reserved for driver internal use */
  67        unsigned int state;
  68
  69#define BL_CORE_SUSPENDED       (1 << 0)        /* backlight is suspended */
  70#define BL_CORE_FBBLANK         (1 << 1)        /* backlight is under an fb blank event */
  71#define BL_CORE_DRIVER4         (1 << 28)       /* reserved for driver specific use */
  72#define BL_CORE_DRIVER3         (1 << 29)       /* reserved for driver specific use */
  73#define BL_CORE_DRIVER2         (1 << 30)       /* reserved for driver specific use */
  74#define BL_CORE_DRIVER1         (1 << 31)       /* reserved for driver specific use */
  75
  76};
  77
  78struct backlight_device {
  79        /* Backlight properties */
  80        struct backlight_properties props;
  81
  82        /* Serialise access to update_status method */
  83        struct mutex update_lock;
  84
  85        /* This protects the 'ops' field. If 'ops' is NULL, the driver that
  86           registered this device has been unloaded, and if class_get_devdata()
  87           points to something in the body of that driver, it is also invalid. */
  88        struct mutex ops_lock;
  89        const struct backlight_ops *ops;
  90
  91        /* The framebuffer notifier block */
  92        struct notifier_block fb_notif;
  93
  94        struct device dev;
  95};
  96
  97static inline void backlight_update_status(struct backlight_device *bd)
  98{
  99        mutex_lock(&bd->update_lock);
 100        if (bd->ops && bd->ops->update_status)
 101                bd->ops->update_status(bd);
 102        mutex_unlock(&bd->update_lock);
 103}
 104
 105extern struct backlight_device *backlight_device_register(const char *name,
 106        struct device *dev, void *devdata, const struct backlight_ops *ops,
 107        const struct backlight_properties *props);
 108extern void backlight_device_unregister(struct backlight_device *bd);
 109extern void backlight_force_update(struct backlight_device *bd,
 110                                   enum backlight_update_reason reason);
 111
 112#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
 113
 114static inline void * bl_get_data(struct backlight_device *bl_dev)
 115{
 116        return dev_get_drvdata(&bl_dev->dev);
 117}
 118
 119struct generic_bl_info {
 120        const char *name;
 121        int max_intensity;
 122        int default_intensity;
 123        int limit_mask;
 124        void (*set_bl_intensity)(int intensity);
 125        void (*kick_battery)(void);
 126};
 127
 128#endif
 129