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
30 enum backlight_update_reason {
31 BACKLIGHT_UPDATE_HOTKEY,
32 BACKLIGHT_UPDATE_SYSFS,
33 };
34
35 enum backlight_type {
36 BACKLIGHT_RAW = 1,
37 BACKLIGHT_PLATFORM,
38 BACKLIGHT_FIRMWARE,
39 BACKLIGHT_TYPE_MAX,
40 };
41
42 struct backlight_device;
43 struct fb_info;
44
45 struct backlight_ops {
46 unsigned int options;
47
48 #define BL_CORE_SUSPENDRESUME (1 << 0)
49
50 /* Notify the backlight driver some property has changed */
51 int (*update_status)(struct backlight_device *);
52 /* Return the current backlight brightness (accounting for power,
53 fb_blank etc.) */
54 int (*get_brightness)(struct backlight_device *);
55 /* Check if given framebuffer device is the one bound to this backlight;
56 return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
57 int (*check_fb)(struct backlight_device *, struct fb_info *);
58 };
59
60 /* This structure defines all the properties of a backlight */
61 struct backlight_properties {
62 /* Current User requested brightness (0 - max_brightness) */
63 int brightness;
64 /* Maximal value for brightness (read-only) */
65 int max_brightness;
66 /* Current FB Power mode (0: full on, 1..3: power saving
67 modes; 4: full off), see FB_BLANK_XXX */
68 int power;
69 /* FB Blanking active? (values as for power) */
70 /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
71 int fb_blank;
72 /* Backlight type */
73 enum backlight_type type;
74 /* Flags used to signal drivers of state changes */
75 /* Upper 4 bits are reserved for driver internal use */
76 unsigned int state;
77
78 #define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
79 #define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
80 #define BL_CORE_DRIVER4 (1 << 28) /* reserved for driver specific use */
81 #define BL_CORE_DRIVER3 (1 << 29) /* reserved for driver specific use */
82 #define BL_CORE_DRIVER2 (1 << 30) /* reserved for driver specific use */
83 #define BL_CORE_DRIVER1 (1 << 31) /* reserved for driver specific use */
84
85 };
86
87 struct backlight_device {
88 /* Backlight properties */
89 struct backlight_properties props;
90
91 /* Serialise access to update_status method */
92 struct mutex update_lock;
93
94 /* This protects the 'ops' field. If 'ops' is NULL, the driver that
95 registered this device has been unloaded, and if class_get_devdata()
96 points to something in the body of that driver, it is also invalid. */
97 struct mutex ops_lock;
98 const struct backlight_ops *ops;
99
100 /* The framebuffer notifier block */
101 struct notifier_block fb_notif;
102
103 struct device dev;
104 };
105
backlight_update_status(struct backlight_device * bd)106 static inline void backlight_update_status(struct backlight_device *bd)
107 {
108 mutex_lock(&bd->update_lock);
109 if (bd->ops && bd->ops->update_status)
110 bd->ops->update_status(bd);
111 mutex_unlock(&bd->update_lock);
112 }
113
114 extern struct backlight_device *backlight_device_register(const char *name,
115 struct device *dev, void *devdata, const struct backlight_ops *ops,
116 const struct backlight_properties *props);
117 extern void backlight_device_unregister(struct backlight_device *bd);
118 extern void backlight_force_update(struct backlight_device *bd,
119 enum backlight_update_reason reason);
120
121 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
122
bl_get_data(struct backlight_device * bl_dev)123 static inline void * bl_get_data(struct backlight_device *bl_dev)
124 {
125 return dev_get_drvdata(&bl_dev->dev);
126 }
127
128 struct generic_bl_info {
129 const char *name;
130 int max_intensity;
131 int default_intensity;
132 int limit_mask;
133 void (*set_bl_intensity)(int intensity);
134 void (*kick_battery)(void);
135 };
136
137 #ifdef CONFIG_OF
138 struct backlight_device *of_find_backlight_by_node(struct device_node *node);
139 #else
140 static inline struct backlight_device *
of_find_backlight_by_node(struct device_node * node)141 of_find_backlight_by_node(struct device_node *node)
142 {
143 return NULL;
144 }
145 #endif
146
147 #endif
148