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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
Linus Torvalds1da177e2005-04-16 15:20:36 -070030struct backlight_device;
31struct fb_info;
32
Richard Purdie599a52d2007-02-10 23:07:48 +000033struct backlight_ops {
Richard Purdie6ca01762006-03-31 02:31:49 -080034 /* Notify the backlight driver some property has changed */
35 int (*update_status)(struct backlight_device *);
36 /* Return the current backlight brightness (accounting for power,
37 fb_blank etc.) */
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 int (*get_brightness)(struct backlight_device *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 /* Check if given framebuffer device is the one bound to this backlight;
40 return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
41 int (*check_fb)(struct fb_info *);
Richard Purdie599a52d2007-02-10 23:07:48 +000042};
Richard Purdie6ca01762006-03-31 02:31:49 -080043
Richard Purdie599a52d2007-02-10 23:07:48 +000044/* This structure defines all the properties of a backlight */
45struct backlight_properties {
Richard Purdie6ca01762006-03-31 02:31:49 -080046 /* Current User requested brightness (0 - max_brightness) */
47 int brightness;
48 /* Maximal value for brightness (read-only) */
49 int max_brightness;
50 /* Current FB Power mode (0: full on, 1..3: power saving
51 modes; 4: full off), see FB_BLANK_XXX */
52 int power;
53 /* FB Blanking active? (values as for power) */
54 int fb_blank;
Linus Torvalds1da177e2005-04-16 15:20:36 -070055};
56
57struct backlight_device {
Richard Purdie599a52d2007-02-10 23:07:48 +000058 /* Backlight properties */
59 struct backlight_properties props;
60
Richard Purdie28ee0862007-02-08 22:25:09 +000061 /* Serialise access to update_status method */
62 struct mutex update_lock;
Richard Purdie599a52d2007-02-10 23:07:48 +000063
64 /* This protects the 'ops' field. If 'ops' is NULL, the driver that
65 registered this device has been unloaded, and if class_get_devdata()
66 points to something in the body of that driver, it is also invalid. */
67 struct mutex ops_lock;
68 struct backlight_ops *ops;
69
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 /* The framebuffer notifier block */
71 struct notifier_block fb_notif;
Richard Purdie655bfd72007-07-09 12:17:24 +010072
73 struct device dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074};
75
Richard Purdie28ee0862007-02-08 22:25:09 +000076static inline void backlight_update_status(struct backlight_device *bd)
77{
78 mutex_lock(&bd->update_lock);
Richard Purdie599a52d2007-02-10 23:07:48 +000079 if (bd->ops && bd->ops->update_status)
80 bd->ops->update_status(bd);
Richard Purdie28ee0862007-02-08 22:25:09 +000081 mutex_unlock(&bd->update_lock);
82}
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084extern struct backlight_device *backlight_device_register(const char *name,
Richard Purdie599a52d2007-02-10 23:07:48 +000085 struct device *dev, void *devdata, struct backlight_ops *ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086extern void backlight_device_unregister(struct backlight_device *bd);
87
Richard Purdie655bfd72007-07-09 12:17:24 +010088#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
89
90static inline void * bl_get_data(struct backlight_device *bl_dev)
91{
92 return dev_get_drvdata(&bl_dev->dev);
93}
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
95#endif