1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
/*
* Driver for the Cirrus EP93xx lcd backlight
*
* Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This driver controls the pulse width modulated brightness control output,
* BRIGHT, on the Cirrus EP9307, EP9312, and EP9315 processors.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#define EP93XX_MAX_COUNT 255
#define EP93XX_MAX_BRIGHT 255
#define EP93XX_DEF_BRIGHT 128
struct ep93xxbl {
void __iomem *mmio;
int brightness;
};
static int ep93xxbl_set(struct backlight_device *bl, int brightness)
{
struct ep93xxbl *ep93xxbl = bl_get_data(bl);
writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio);
ep93xxbl->brightness = brightness;
return 0;
}
static int ep93xxbl_update_status(struct backlight_device *bl)
{
int brightness = bl->props.brightness;
if (bl->props.power != FB_BLANK_UNBLANK ||
bl->props.fb_blank != FB_BLANK_UNBLANK)
brightness = 0;
return ep93xxbl_set(bl, brightness);
}
static int ep93xxbl_get_brightness(struct backlight_device *bl)
{
struct ep93xxbl *ep93xxbl = bl_get_data(bl);
return ep93xxbl->brightness;
}
static const struct backlight_ops ep93xxbl_ops = {
.update_status = ep93xxbl_update_status,
.get_brightness = ep93xxbl_get_brightness,
};
static int ep93xxbl_probe(struct platform_device *dev)
{
struct ep93xxbl *ep93xxbl;
struct backlight_device *bl;
struct backlight_properties props;
struct resource *res;
ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL);
if (!ep93xxbl)
return -ENOMEM;
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (!res)
return -ENXIO;
/*
* FIXME - We don't do a request_mem_region here because we are
* sharing the register space with the framebuffer driver (see
* drivers/video/ep93xx-fb.c) and doing so will cause the second
* loaded driver to return -EBUSY.
*
* NOTE: No locking is required; the framebuffer does not touch
* this register.
*/
ep93xxbl->mmio = devm_ioremap(&dev->dev, res->start,
resource_size(res));
if (!ep93xxbl->mmio)
return -ENXIO;
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_RAW;
props.max_brightness = EP93XX_MAX_BRIGHT;
bl = backlight_device_register(dev->name, &dev->dev, ep93xxbl,
&ep93xxbl_ops, &props);
if (IS_ERR(bl))
return PTR_ERR(bl);
bl->props.brightness = EP93XX_DEF_BRIGHT;
platform_set_drvdata(dev, bl);
ep93xxbl_update_status(bl);
return 0;
}
static int ep93xxbl_remove(struct platform_device *dev)
{
struct backlight_device *bl = platform_get_drvdata(dev);
backlight_device_unregister(bl);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int ep93xxbl_suspend(struct device *dev)
{
struct backlight_device *bl = dev_get_drvdata(dev);
return ep93xxbl_set(bl, 0);
}
static int ep93xxbl_resume(struct device *dev)
{
struct backlight_device *bl = dev_get_drvdata(dev);
backlight_update_status(bl);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(ep93xxbl_pm_ops, ep93xxbl_suspend, ep93xxbl_resume);
static struct platform_driver ep93xxbl_driver = {
.driver = {
.name = "ep93xx-bl",
.owner = THIS_MODULE,
.pm = &ep93xxbl_pm_ops,
},
.probe = ep93xxbl_probe,
.remove = ep93xxbl_remove,
};
module_platform_driver(ep93xxbl_driver);
MODULE_DESCRIPTION("EP93xx Backlight Driver");
MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ep93xx-bl");
|
