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
  30 struct backlight_device;
  31 struct fb_info;
  32
  33 struct 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 */
  49 struct 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
  73 struct 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
  92 static 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
 100 extern struct backlight_device *backlight_device_register(const char *name,
 101         struct device *dev, void *devdata, struct backlight_ops *ops);
 102 extern void backlight_device_unregister(struct backlight_device *bd);
 103
 104 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
 105
 106 static inline void * bl_get_data(struct backlight_device *bl_dev)
 107 {
 108         return dev_get_drvdata(&bl_dev->dev);
 109 }
 110
 111 struct 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