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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Richard Purdie28ee0862007-02-08 22:25:09 +000012#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/notifier.h>
14
Richard Purdie28ee0862007-02-08 22:25:09 +000015/* Notes on locking:
16 *
Richard Purdie599a52d2007-02-10 23:07:48 +000017 * 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.
Richard Purdie28ee0862007-02-08 22:25:09 +000019 *
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
Matthew Garrett325253a2009-07-14 17:06:02 +010030enum backlight_update_reason {
31 BACKLIGHT_UPDATE_HOTKEY,
32 BACKLIGHT_UPDATE_SYSFS,
33};
34
Linus Torvalds1da177e2005-04-16 15:20:36 -070035struct backlight_device;
36struct fb_info;
37
Richard Purdie599a52d2007-02-10 23:07:48 +000038struct backlight_ops {
Richard Purdiec835ee72009-01-06 21:00:19 +000039 unsigned int options;
40
41#define BL_CORE_SUSPENDRESUME (1 << 0)
42
Richard Purdie6ca01762006-03-31 02:31:49 -080043 /* 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.) */
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 int (*get_brightness)(struct backlight_device *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 /* 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 fb_info *);
Richard Purdie599a52d2007-02-10 23:07:48 +000051};
Richard Purdie6ca01762006-03-31 02:31:49 -080052
Richard Purdie599a52d2007-02-10 23:07:48 +000053/* This structure defines all the properties of a backlight */
54struct backlight_properties {
Richard Purdie6ca01762006-03-31 02:31:49 -080055 /* 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) */
Richard Purdiec835ee72009-01-06 21:00:19 +000063 /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
Richard Purdie6ca01762006-03-31 02:31:49 -080064 int fb_blank;
Richard Purdiec835ee72009-01-06 21:00:19 +000065 /* 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070076};
77
78struct backlight_device {
Richard Purdie599a52d2007-02-10 23:07:48 +000079 /* Backlight properties */
80 struct backlight_properties props;
81
Richard Purdie28ee0862007-02-08 22:25:09 +000082 /* Serialise access to update_status method */
83 struct mutex update_lock;
Richard Purdie599a52d2007-02-10 23:07:48 +000084
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 struct backlight_ops *ops;
90
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 /* The framebuffer notifier block */
92 struct notifier_block fb_notif;
Richard Purdie655bfd72007-07-09 12:17:24 +010093
94 struct device dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095};
96
Richard Purdie28ee0862007-02-08 22:25:09 +000097static inline void backlight_update_status(struct backlight_device *bd)
98{
99 mutex_lock(&bd->update_lock);
Richard Purdie599a52d2007-02-10 23:07:48 +0000100 if (bd->ops && bd->ops->update_status)
101 bd->ops->update_status(bd);
Richard Purdie28ee0862007-02-08 22:25:09 +0000102 mutex_unlock(&bd->update_lock);
103}
104
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105extern struct backlight_device *backlight_device_register(const char *name,
Richard Purdie599a52d2007-02-10 23:07:48 +0000106 struct device *dev, void *devdata, struct backlight_ops *ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107extern void backlight_device_unregister(struct backlight_device *bd);
Matthew Garrett325253a2009-07-14 17:06:02 +0100108extern void backlight_force_update(struct backlight_device *bd,
109 enum backlight_update_reason reason);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
Richard Purdie655bfd72007-07-09 12:17:24 +0100111#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
112
113static inline void * bl_get_data(struct backlight_device *bl_dev)
114{
115 return dev_get_drvdata(&bl_dev->dev);
116}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
Richard Purdiec3f8f652007-09-03 00:27:00 +0100118struct generic_bl_info {
119 const char *name;
120 int max_intensity;
121 int default_intensity;
122 int limit_mask;
123 void (*set_bl_intensity)(int intensity);
124 void (*kick_battery)(void);
125};
126
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127#endif