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Richard Purdied00ba722009-01-08 20:52:37 +00001/*
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
20static int genericbl_intensity;
21static struct backlight_device *generic_backlight_device;
22static struct generic_bl_info *bl_machinfo;
23
24/* Flag to signal when the battery is low */
25#define GENERICBL_BATTLOW BL_CORE_DRIVER1
26
27static 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
50static 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 */
Axel Lin1bff3a22011-10-31 17:11:52 -070059void genericbl_limit_intensity(int limit)
Richard Purdied00ba722009-01-08 20:52:37 +000060{
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}
Axel Lin1bff3a22011-10-31 17:11:52 -070071EXPORT_SYMBOL(genericbl_limit_intensity);
Richard Purdied00ba722009-01-08 20:52:37 +000072
Emese Revfy9905a432009-12-14 00:58:57 +010073static const struct backlight_ops genericbl_ops = {
Richard Purdied00ba722009-01-08 20:52:37 +000074 .options = BL_CORE_SUSPENDRESUME,
75 .get_brightness = genericbl_get_intensity,
76 .update_status = genericbl_send_intensity,
77};
78
79static int genericbl_probe(struct platform_device *pdev)
80{
Matthew Garretta19a6ee2010-02-17 16:39:44 -050081 struct backlight_properties props;
Richard Purdied00ba722009-01-08 20:52:37 +000082 struct generic_bl_info *machinfo = pdev->dev.platform_data;
83 const char *name = "generic-bl";
84 struct backlight_device *bd;
85
86 bl_machinfo = machinfo;
87 if (!machinfo->limit_mask)
88 machinfo->limit_mask = -1;
89
90 if (machinfo->name)
91 name = machinfo->name;
92
Matthew Garretta19a6ee2010-02-17 16:39:44 -050093 memset(&props, 0, sizeof(struct backlight_properties));
Matthew Garrettbb7ca742011-03-22 16:30:21 -070094 props.type = BACKLIGHT_RAW;
Matthew Garretta19a6ee2010-02-17 16:39:44 -050095 props.max_brightness = machinfo->max_intensity;
96 bd = backlight_device_register(name, &pdev->dev, NULL, &genericbl_ops,
97 &props);
Richard Purdied00ba722009-01-08 20:52:37 +000098 if (IS_ERR (bd))
99 return PTR_ERR (bd);
100
101 platform_set_drvdata(pdev, bd);
102
Richard Purdied00ba722009-01-08 20:52:37 +0000103 bd->props.power = FB_BLANK_UNBLANK;
104 bd->props.brightness = machinfo->default_intensity;
105 backlight_update_status(bd);
106
107 generic_backlight_device = bd;
108
109 printk("Generic Backlight Driver Initialized.\n");
110 return 0;
111}
112
113static int genericbl_remove(struct platform_device *pdev)
114{
115 struct backlight_device *bd = platform_get_drvdata(pdev);
116
117 bd->props.power = 0;
118 bd->props.brightness = 0;
119 backlight_update_status(bd);
120
121 backlight_device_unregister(bd);
122
123 printk("Generic Backlight Driver Unloaded\n");
124 return 0;
125}
126
127static struct platform_driver genericbl_driver = {
128 .probe = genericbl_probe,
129 .remove = genericbl_remove,
130 .driver = {
131 .name = "generic-bl",
132 },
133};
134
135static int __init genericbl_init(void)
136{
137 return platform_driver_register(&genericbl_driver);
138}
139
140static void __exit genericbl_exit(void)
141{
142 platform_driver_unregister(&genericbl_driver);
143}
144
145module_init(genericbl_init);
146module_exit(genericbl_exit);
147
148MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
149MODULE_DESCRIPTION("Generic Backlight Driver");
150MODULE_LICENSE("GPL");