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
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 */
59void genericbl_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}
71EXPORT_SYMBOL(genericbl_limit_intensity);
72
73static const struct backlight_ops genericbl_ops = {
74	.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{
81	struct backlight_properties props;
82	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
93	memset(&props, 0, sizeof(struct backlight_properties));
94	props.type = BACKLIGHT_RAW;
95	props.max_brightness = machinfo->max_intensity;
96	bd = backlight_device_register(name, &pdev->dev, NULL, &genericbl_ops,
97				       &props);
98	if (IS_ERR (bd))
99		return PTR_ERR (bd);
100
101	platform_set_drvdata(pdev, bd);
102
103	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
135module_platform_driver(genericbl_driver);
136
137MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
138MODULE_DESCRIPTION("Generic Backlight Driver");
139MODULE_LICENSE("GPL");
140