Merge git://bedivere.hansenpartnership.com/git/scsi-rc-fixes-2.6
[linux-2.6.git] / drivers / video / backlight / ep93xx_bl.c
1 /*
2  * Driver for the Cirrus EP93xx lcd backlight
3  *
4  * Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.com>
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  * This driver controls the pulse width modulated brightness control output,
11  * BRIGHT, on the Cirrus EP9307, EP9312, and EP9315 processors.
12  */
13
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/io.h>
17 #include <linux/fb.h>
18 #include <linux/backlight.h>
19
20 #include <mach/hardware.h>
21
22 #define EP93XX_RASTER_REG(x)            (EP93XX_RASTER_BASE + (x))
23 #define EP93XX_RASTER_BRIGHTNESS        EP93XX_RASTER_REG(0x20)
24
25 #define EP93XX_MAX_COUNT                255
26 #define EP93XX_MAX_BRIGHT               255
27 #define EP93XX_DEF_BRIGHT               128
28
29 struct ep93xxbl {
30         void __iomem *mmio;
31         int brightness;
32 };
33
34 static int ep93xxbl_set(struct backlight_device *bl, int brightness)
35 {
36         struct ep93xxbl *ep93xxbl = bl_get_data(bl);
37
38         __raw_writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio);
39
40         ep93xxbl->brightness = brightness;
41
42         return 0;
43 }
44
45 static int ep93xxbl_update_status(struct backlight_device *bl)
46 {
47         int brightness = bl->props.brightness;
48
49         if (bl->props.power != FB_BLANK_UNBLANK ||
50             bl->props.fb_blank != FB_BLANK_UNBLANK)
51                 brightness = 0;
52
53         return ep93xxbl_set(bl, brightness);
54 }
55
56 static int ep93xxbl_get_brightness(struct backlight_device *bl)
57 {
58         struct ep93xxbl *ep93xxbl = bl_get_data(bl);
59
60         return ep93xxbl->brightness;
61 }
62
63 static const struct backlight_ops ep93xxbl_ops = {
64         .update_status  = ep93xxbl_update_status,
65         .get_brightness = ep93xxbl_get_brightness,
66 };
67
68 static int __init ep93xxbl_probe(struct platform_device *dev)
69 {
70         struct ep93xxbl *ep93xxbl;
71         struct backlight_device *bl;
72         struct backlight_properties props;
73
74         ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL);
75         if (!ep93xxbl)
76                 return -ENOMEM;
77
78         /*
79          * This register is located in the range already ioremap'ed by
80          * the framebuffer driver.  A MFD driver seems a bit of overkill
81          * to handle this so use the static I/O mapping; this address
82          * is already virtual.
83          *
84          * NOTE: No locking is required; the framebuffer does not touch
85          * this register.
86          */
87         ep93xxbl->mmio = EP93XX_RASTER_BRIGHTNESS;
88
89         memset(&props, 0, sizeof(struct backlight_properties));
90         props.type = BACKLIGHT_RAW;
91         props.max_brightness = EP93XX_MAX_BRIGHT;
92         bl = backlight_device_register(dev->name, &dev->dev, ep93xxbl,
93                                        &ep93xxbl_ops, &props);
94         if (IS_ERR(bl))
95                 return PTR_ERR(bl);
96
97         bl->props.brightness = EP93XX_DEF_BRIGHT;
98
99         platform_set_drvdata(dev, bl);
100
101         ep93xxbl_update_status(bl);
102
103         return 0;
104 }
105
106 static int ep93xxbl_remove(struct platform_device *dev)
107 {
108         struct backlight_device *bl = platform_get_drvdata(dev);
109
110         backlight_device_unregister(bl);
111         platform_set_drvdata(dev, NULL);
112         return 0;
113 }
114
115 #ifdef CONFIG_PM
116 static int ep93xxbl_suspend(struct platform_device *dev, pm_message_t state)
117 {
118         struct backlight_device *bl = platform_get_drvdata(dev);
119
120         return ep93xxbl_set(bl, 0);
121 }
122
123 static int ep93xxbl_resume(struct platform_device *dev)
124 {
125         struct backlight_device *bl = platform_get_drvdata(dev);
126
127         backlight_update_status(bl);
128         return 0;
129 }
130 #else
131 #define ep93xxbl_suspend        NULL
132 #define ep93xxbl_resume         NULL
133 #endif
134
135 static struct platform_driver ep93xxbl_driver = {
136         .driver         = {
137                 .name   = "ep93xx-bl",
138                 .owner  = THIS_MODULE,
139         },
140         .probe          = ep93xxbl_probe,
141         .remove         = __devexit_p(ep93xxbl_remove),
142         .suspend        = ep93xxbl_suspend,
143         .resume         = ep93xxbl_resume,
144 };
145
146 static int __init ep93xxbl_init(void)
147 {
148         return platform_driver_register(&ep93xxbl_driver);
149 }
150 module_init(ep93xxbl_init);
151
152 static void __exit ep93xxbl_exit(void)
153 {
154         platform_driver_unregister(&ep93xxbl_driver);
155 }
156 module_exit(ep93xxbl_exit);
157
158 MODULE_DESCRIPTION("EP93xx Backlight Driver");
159 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
160 MODULE_LICENSE("GPL");
161 MODULE_ALIAS("platform:ep93xx-bl");