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
genericbl_send_intensity(struct backlight_device * bd)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
genericbl_get_intensity(struct backlight_device * bd)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 */
corgibl_limit_intensity(int limit)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
genericbl_probe(struct platform_device * pdev)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
genericbl_remove(struct platform_device * pdev)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
genericbl_init(void)132 static int __init genericbl_init(void)
133 {
134 return platform_driver_register(&genericbl_driver);
135 }
136
genericbl_exit(void)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");
148