Commit | Line | Data |
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1da177e4 LT |
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> | |
28ee086d | 12 | #include <linux/mutex.h> |
1da177e4 LT |
13 | #include <linux/notifier.h> |
14 | ||
28ee086d RP |
15 | /* Notes on locking: |
16 | * | |
249040dc RP |
17 | * backlight_device->props_lock is an internal backlight lock protecting the |
18 | * props field and no code outside the core should need to touch it. | |
28ee086d RP |
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 | ||
1da177e4 LT |
30 | struct backlight_device; |
31 | struct fb_info; | |
32 | ||
33 | /* This structure defines all the properties of a backlight | |
34 | (usually attached to a LCD). */ | |
35 | struct backlight_properties { | |
6ca01765 RP |
36 | /* Notify the backlight driver some property has changed */ |
37 | int (*update_status)(struct backlight_device *); | |
38 | /* Return the current backlight brightness (accounting for power, | |
39 | fb_blank etc.) */ | |
1da177e4 | 40 | int (*get_brightness)(struct backlight_device *); |
1da177e4 LT |
41 | /* Check if given framebuffer device is the one bound to this backlight; |
42 | return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */ | |
43 | int (*check_fb)(struct fb_info *); | |
6ca01765 RP |
44 | |
45 | /* Current User requested brightness (0 - max_brightness) */ | |
46 | int brightness; | |
47 | /* Maximal value for brightness (read-only) */ | |
48 | int max_brightness; | |
49 | /* Current FB Power mode (0: full on, 1..3: power saving | |
50 | modes; 4: full off), see FB_BLANK_XXX */ | |
51 | int power; | |
52 | /* FB Blanking active? (values as for power) */ | |
53 | int fb_blank; | |
1da177e4 LT |
54 | }; |
55 | ||
56 | struct backlight_device { | |
57 | /* This protects the 'props' field. If 'props' is NULL, the driver that | |
58 | registered this device has been unloaded, and if class_get_devdata() | |
59 | points to something in the body of that driver, it is also invalid. */ | |
249040dc | 60 | struct mutex props_lock; |
1da177e4 LT |
61 | /* If this is NULL, the backing module is unloaded */ |
62 | struct backlight_properties *props; | |
28ee086d RP |
63 | /* Serialise access to update_status method */ |
64 | struct mutex update_lock; | |
1da177e4 LT |
65 | /* The framebuffer notifier block */ |
66 | struct notifier_block fb_notif; | |
67 | /* The class device structure */ | |
68 | struct class_device class_dev; | |
69 | }; | |
70 | ||
28ee086d RP |
71 | static inline void backlight_update_status(struct backlight_device *bd) |
72 | { | |
73 | mutex_lock(&bd->update_lock); | |
74 | if (bd->props && bd->props->update_status) | |
75 | bd->props->update_status(bd); | |
76 | mutex_unlock(&bd->update_lock); | |
77 | } | |
78 | ||
1da177e4 | 79 | extern struct backlight_device *backlight_device_register(const char *name, |
519ab5f2 | 80 | struct device *dev,void *devdata,struct backlight_properties *bp); |
1da177e4 LT |
81 | extern void backlight_device_unregister(struct backlight_device *bd); |
82 | ||
83 | #define to_backlight_device(obj) container_of(obj, struct backlight_device, class_dev) | |
84 | ||
85 | #endif |