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linux
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