Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Richard Purdie | 28ee086 | 2007-02-08 22:25:09 +0000 | [diff] [blame] | 12 | #include <linux/mutex.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | #include <linux/notifier.h> |
| 14 | |
Richard Purdie | 28ee086 | 2007-02-08 22:25:09 +0000 | [diff] [blame] | 15 | /* Notes on locking: |
| 16 | * |
Richard Purdie | 599a52d | 2007-02-10 23:07:48 +0000 | [diff] [blame] | 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. |
Richard Purdie | 28ee086 | 2007-02-08 22:25:09 +0000 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | struct backlight_device; |
| 31 | struct fb_info; |
| 32 | |
Richard Purdie | 599a52d | 2007-02-10 23:07:48 +0000 | [diff] [blame] | 33 | struct backlight_ops { |
Richard Purdie | 6ca0176 | 2006-03-31 02:31:49 -0800 | [diff] [blame] | 34 | /* 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | int (*get_brightness)(struct backlight_device *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | /* 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 Purdie | 599a52d | 2007-02-10 23:07:48 +0000 | [diff] [blame] | 42 | }; |
Richard Purdie | 6ca0176 | 2006-03-31 02:31:49 -0800 | [diff] [blame] | 43 | |
Richard Purdie | 599a52d | 2007-02-10 23:07:48 +0000 | [diff] [blame] | 44 | /* This structure defines all the properties of a backlight */ |
| 45 | struct backlight_properties { |
Richard Purdie | 6ca0176 | 2006-03-31 02:31:49 -0800 | [diff] [blame] | 46 | /* 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | }; |
| 56 | |
| 57 | struct backlight_device { |
Richard Purdie | 599a52d | 2007-02-10 23:07:48 +0000 | [diff] [blame] | 58 | /* Backlight properties */ |
| 59 | struct backlight_properties props; |
| 60 | |
Richard Purdie | 28ee086 | 2007-02-08 22:25:09 +0000 | [diff] [blame] | 61 | /* Serialise access to update_status method */ |
| 62 | struct mutex update_lock; |
Richard Purdie | 599a52d | 2007-02-10 23:07:48 +0000 | [diff] [blame] | 63 | |
| 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 Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | /* The framebuffer notifier block */ |
| 71 | struct notifier_block fb_notif; |
Richard Purdie | 655bfd7 | 2007-07-09 12:17:24 +0100 | [diff] [blame] | 72 | |
| 73 | struct device dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | }; |
| 75 | |
Richard Purdie | 28ee086 | 2007-02-08 22:25:09 +0000 | [diff] [blame] | 76 | static inline void backlight_update_status(struct backlight_device *bd) |
| 77 | { |
| 78 | mutex_lock(&bd->update_lock); |
Richard Purdie | 599a52d | 2007-02-10 23:07:48 +0000 | [diff] [blame] | 79 | if (bd->ops && bd->ops->update_status) |
| 80 | bd->ops->update_status(bd); |
Richard Purdie | 28ee086 | 2007-02-08 22:25:09 +0000 | [diff] [blame] | 81 | mutex_unlock(&bd->update_lock); |
| 82 | } |
| 83 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | extern struct backlight_device *backlight_device_register(const char *name, |
Richard Purdie | 599a52d | 2007-02-10 23:07:48 +0000 | [diff] [blame] | 85 | struct device *dev, void *devdata, struct backlight_ops *ops); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | extern void backlight_device_unregister(struct backlight_device *bd); |
| 87 | |
Richard Purdie | 655bfd7 | 2007-07-09 12:17:24 +0100 | [diff] [blame] | 88 | #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev) |
| 89 | |
| 90 | static inline void * bl_get_data(struct backlight_device *bl_dev) |
| 91 | { |
| 92 | return dev_get_drvdata(&bl_dev->dev); |
| 93 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | |
| 95 | #endif |