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/fb.h>
13 #include <linux/mutex.h>
14 #include <linux/notifier.h>
15
16 /* Notes on locking:
17 *
18 * backlight_device->ops_lock is an internal backlight lock protecting the
19 * ops pointer and no code outside the core should need to touch it.
20 *
21 * Access to update_status() is serialised by the update_lock mutex since
22 * most drivers seem to need this and historically get it wrong.
23 *
24 * Most drivers don't need locking on their get_brightness() method.
25 * If yours does, you need to implement it in the driver. You can use the
26 * update_lock mutex if appropriate.
27 *
28 * Any other use of the locks below is probably wrong.
29 */
30
31 enum backlight_update_reason {
32 BACKLIGHT_UPDATE_HOTKEY,
33 BACKLIGHT_UPDATE_SYSFS,
34 };
35
36 enum backlight_type {
37 BACKLIGHT_RAW = 1,
38 BACKLIGHT_PLATFORM,
39 BACKLIGHT_FIRMWARE,
40 BACKLIGHT_TYPE_MAX,
41 };
42
43 enum backlight_notification {
44 BACKLIGHT_REGISTERED,
45 BACKLIGHT_UNREGISTERED,
46 };
47
48 struct backlight_device;
49 struct fb_info;
50
51 struct backlight_ops {
52 unsigned int options;
53
54 #define BL_CORE_SUSPENDRESUME (1 << 0)
55
56 /* Notify the backlight driver some property has changed */
57 int (*update_status)(struct backlight_device *);
58 /* Return the current backlight brightness (accounting for power,
59 fb_blank etc.) */
60 int (*get_brightness)(struct backlight_device *);
61 /* Check if given framebuffer device is the one bound to this backlight;
62 return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
63 int (*check_fb)(struct backlight_device *, struct fb_info *);
64 };
65
66 /* This structure defines all the properties of a backlight */
67 struct backlight_properties {
68 /* Current User requested brightness (0 - max_brightness) */
69 int brightness;
70 /* Maximal value for brightness (read-only) */
71 int max_brightness;
72 /* Current FB Power mode (0: full on, 1..3: power saving
73 modes; 4: full off), see FB_BLANK_XXX */
74 int power;
75 /* FB Blanking active? (values as for power) */
76 /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
77 int fb_blank;
78 /* Backlight type */
79 enum backlight_type type;
80 /* Flags used to signal drivers of state changes */
81 /* Upper 4 bits are reserved for driver internal use */
82 unsigned int state;
83
84 #define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
85 #define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
86 #define BL_CORE_DRIVER4 (1 << 28) /* reserved for driver specific use */
87 #define BL_CORE_DRIVER3 (1 << 29) /* reserved for driver specific use */
88 #define BL_CORE_DRIVER2 (1 << 30) /* reserved for driver specific use */
89 #define BL_CORE_DRIVER1 (1 << 31) /* reserved for driver specific use */
90
91 };
92
93 struct backlight_device {
94 /* Backlight properties */
95 struct backlight_properties props;
96
97 /* Serialise access to update_status method */
98 struct mutex update_lock;
99
100 /* This protects the 'ops' field. If 'ops' is NULL, the driver that
101 registered this device has been unloaded, and if class_get_devdata()
102 points to something in the body of that driver, it is also invalid. */
103 struct mutex ops_lock;
104 const struct backlight_ops *ops;
105
106 /* The framebuffer notifier block */
107 struct notifier_block fb_notif;
108
109 /* list entry of all registered backlight devices */
110 struct list_head entry;
111
112 struct device dev;
113
114 /* Multiple framebuffers may share one backlight device */
115 bool fb_bl_on[FB_MAX];
116
117 int use_count;
118 };
119
backlight_update_status(struct backlight_device * bd)120 static inline int backlight_update_status(struct backlight_device *bd)
121 {
122 int ret = -ENOENT;
123
124 mutex_lock(&bd->update_lock);
125 if (bd->ops && bd->ops->update_status)
126 ret = bd->ops->update_status(bd);
127 mutex_unlock(&bd->update_lock);
128
129 return ret;
130 }
131
132 extern struct backlight_device *backlight_device_register(const char *name,
133 struct device *dev, void *devdata, const struct backlight_ops *ops,
134 const struct backlight_properties *props);
135 extern struct backlight_device *devm_backlight_device_register(
136 struct device *dev, const char *name, struct device *parent,
137 void *devdata, const struct backlight_ops *ops,
138 const struct backlight_properties *props);
139 extern void backlight_device_unregister(struct backlight_device *bd);
140 extern void devm_backlight_device_unregister(struct device *dev,
141 struct backlight_device *bd);
142 extern void backlight_force_update(struct backlight_device *bd,
143 enum backlight_update_reason reason);
144 extern bool backlight_device_registered(enum backlight_type type);
145 extern int backlight_register_notifier(struct notifier_block *nb);
146 extern int backlight_unregister_notifier(struct notifier_block *nb);
147
148 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
149
bl_get_data(struct backlight_device * bl_dev)150 static inline void * bl_get_data(struct backlight_device *bl_dev)
151 {
152 return dev_get_drvdata(&bl_dev->dev);
153 }
154
155 struct generic_bl_info {
156 const char *name;
157 int max_intensity;
158 int default_intensity;
159 int limit_mask;
160 void (*set_bl_intensity)(int intensity);
161 void (*kick_battery)(void);
162 };
163
164 #ifdef CONFIG_OF
165 struct backlight_device *of_find_backlight_by_node(struct device_node *node);
166 #else
167 static inline struct backlight_device *
of_find_backlight_by_node(struct device_node * node)168 of_find_backlight_by_node(struct device_node *node)
169 {
170 return NULL;
171 }
172 #endif
173
174 #endif
175