Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
[linux-2.6] / drivers / video / backlight / generic_bl.c
1 /*
2  *  Generic Backlight Driver
3  *
4  *  Copyright (c) 2004-2008 Richard Purdie
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License version 2 as
8  *  published by the Free Software Foundation.
9  *
10  */
11
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/platform_device.h>
16 #include <linux/mutex.h>
17 #include <linux/fb.h>
18 #include <linux/backlight.h>
19
20 static int genericbl_intensity;
21 static struct backlight_device *generic_backlight_device;
22 static struct generic_bl_info *bl_machinfo;
23
24 /* Flag to signal when the battery is low */
25 #define GENERICBL_BATTLOW       BL_CORE_DRIVER1
26
27 static int genericbl_send_intensity(struct backlight_device *bd)
28 {
29         int intensity = bd->props.brightness;
30
31         if (bd->props.power != FB_BLANK_UNBLANK)
32                 intensity = 0;
33         if (bd->props.state & BL_CORE_FBBLANK)
34                 intensity = 0;
35         if (bd->props.state & BL_CORE_SUSPENDED)
36                 intensity = 0;
37         if (bd->props.state & GENERICBL_BATTLOW)
38                 intensity &= bl_machinfo->limit_mask;
39
40         bl_machinfo->set_bl_intensity(intensity);
41
42         genericbl_intensity = intensity;
43
44         if (bl_machinfo->kick_battery)
45                 bl_machinfo->kick_battery();
46
47         return 0;
48 }
49
50 static int genericbl_get_intensity(struct backlight_device *bd)
51 {
52         return genericbl_intensity;
53 }
54
55 /*
56  * Called when the battery is low to limit the backlight intensity.
57  * If limit==0 clear any limit, otherwise limit the intensity
58  */
59 void corgibl_limit_intensity(int limit)
60 {
61         struct backlight_device *bd = generic_backlight_device;
62
63         mutex_lock(&bd->ops_lock);
64         if (limit)
65                 bd->props.state |= GENERICBL_BATTLOW;
66         else
67                 bd->props.state &= ~GENERICBL_BATTLOW;
68         backlight_update_status(generic_backlight_device);
69         mutex_unlock(&bd->ops_lock);
70 }
71 EXPORT_SYMBOL(corgibl_limit_intensity);
72
73 static struct backlight_ops genericbl_ops = {
74         .options = BL_CORE_SUSPENDRESUME,
75         .get_brightness = genericbl_get_intensity,
76         .update_status  = genericbl_send_intensity,
77 };
78
79 static int genericbl_probe(struct platform_device *pdev)
80 {
81         struct generic_bl_info *machinfo = pdev->dev.platform_data;
82         const char *name = "generic-bl";
83         struct backlight_device *bd;
84
85         bl_machinfo = machinfo;
86         if (!machinfo->limit_mask)
87                 machinfo->limit_mask = -1;
88
89         if (machinfo->name)
90                 name = machinfo->name;
91
92         bd = backlight_device_register (name,
93                 &pdev->dev, NULL, &genericbl_ops);
94         if (IS_ERR (bd))
95                 return PTR_ERR (bd);
96
97         platform_set_drvdata(pdev, bd);
98
99         bd->props.max_brightness = machinfo->max_intensity;
100         bd->props.power = FB_BLANK_UNBLANK;
101         bd->props.brightness = machinfo->default_intensity;
102         backlight_update_status(bd);
103
104         generic_backlight_device = bd;
105
106         printk("Generic Backlight Driver Initialized.\n");
107         return 0;
108 }
109
110 static int genericbl_remove(struct platform_device *pdev)
111 {
112         struct backlight_device *bd = platform_get_drvdata(pdev);
113
114         bd->props.power = 0;
115         bd->props.brightness = 0;
116         backlight_update_status(bd);
117
118         backlight_device_unregister(bd);
119
120         printk("Generic Backlight Driver Unloaded\n");
121         return 0;
122 }
123
124 static struct platform_driver genericbl_driver = {
125         .probe          = genericbl_probe,
126         .remove         = genericbl_remove,
127         .driver         = {
128                 .name   = "generic-bl",
129         },
130 };
131
132 static int __init genericbl_init(void)
133 {
134         return platform_driver_register(&genericbl_driver);
135 }
136
137 static void __exit genericbl_exit(void)
138 {
139         platform_driver_unregister(&genericbl_driver);
140 }
141
142 module_init(genericbl_init);
143 module_exit(genericbl_exit);
144
145 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
146 MODULE_DESCRIPTION("Generic Backlight Driver");
147 MODULE_LICENSE("GPL");