Commit | Line | Data |
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08b3924b HS |
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 | ||
15b1a8f2 | 14 | #include <linux/module.h> |
08b3924b HS |
15 | #include <linux/platform_device.h> |
16 | #include <linux/io.h> | |
17 | #include <linux/fb.h> | |
18 | #include <linux/backlight.h> | |
19 | ||
08b3924b HS |
20 | #define EP93XX_MAX_COUNT 255 |
21 | #define EP93XX_MAX_BRIGHT 255 | |
22 | #define EP93XX_DEF_BRIGHT 128 | |
23 | ||
24 | struct ep93xxbl { | |
25 | void __iomem *mmio; | |
26 | int brightness; | |
27 | }; | |
28 | ||
29 | static int ep93xxbl_set(struct backlight_device *bl, int brightness) | |
30 | { | |
31 | struct ep93xxbl *ep93xxbl = bl_get_data(bl); | |
32 | ||
0fd19580 | 33 | writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio); |
08b3924b HS |
34 | |
35 | ep93xxbl->brightness = brightness; | |
36 | ||
37 | return 0; | |
38 | } | |
39 | ||
40 | static int ep93xxbl_update_status(struct backlight_device *bl) | |
41 | { | |
42 | int brightness = bl->props.brightness; | |
43 | ||
44 | if (bl->props.power != FB_BLANK_UNBLANK || | |
45 | bl->props.fb_blank != FB_BLANK_UNBLANK) | |
46 | brightness = 0; | |
47 | ||
48 | return ep93xxbl_set(bl, brightness); | |
49 | } | |
50 | ||
51 | static int ep93xxbl_get_brightness(struct backlight_device *bl) | |
52 | { | |
53 | struct ep93xxbl *ep93xxbl = bl_get_data(bl); | |
54 | ||
55 | return ep93xxbl->brightness; | |
56 | } | |
57 | ||
58 | static const struct backlight_ops ep93xxbl_ops = { | |
59 | .update_status = ep93xxbl_update_status, | |
60 | .get_brightness = ep93xxbl_get_brightness, | |
61 | }; | |
62 | ||
63 | static int __init ep93xxbl_probe(struct platform_device *dev) | |
64 | { | |
65 | struct ep93xxbl *ep93xxbl; | |
66 | struct backlight_device *bl; | |
67 | struct backlight_properties props; | |
0fd19580 | 68 | struct resource *res; |
08b3924b HS |
69 | |
70 | ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL); | |
71 | if (!ep93xxbl) | |
72 | return -ENOMEM; | |
73 | ||
0fd19580 RM |
74 | res = platform_get_resource(dev, IORESOURCE_MEM, 0); |
75 | if (!res) | |
76 | return -ENXIO; | |
77 | ||
08b3924b | 78 | /* |
0fd19580 RM |
79 | * FIXME - We don't do a request_mem_region here because we are |
80 | * sharing the register space with the framebuffer driver (see | |
81 | * drivers/video/ep93xx-fb.c) and doing so will cause the second | |
82 | * loaded driver to return -EBUSY. | |
08b3924b HS |
83 | * |
84 | * NOTE: No locking is required; the framebuffer does not touch | |
85 | * this register. | |
86 | */ | |
0fd19580 RM |
87 | ep93xxbl->mmio = devm_ioremap(&dev->dev, res->start, |
88 | resource_size(res)); | |
89 | if (!ep93xxbl->mmio) | |
90 | return -ENXIO; | |
08b3924b HS |
91 | |
92 | memset(&props, 0, sizeof(struct backlight_properties)); | |
bb7ca747 | 93 | props.type = BACKLIGHT_RAW; |
08b3924b HS |
94 | props.max_brightness = EP93XX_MAX_BRIGHT; |
95 | bl = backlight_device_register(dev->name, &dev->dev, ep93xxbl, | |
96 | &ep93xxbl_ops, &props); | |
97 | if (IS_ERR(bl)) | |
98 | return PTR_ERR(bl); | |
99 | ||
100 | bl->props.brightness = EP93XX_DEF_BRIGHT; | |
101 | ||
102 | platform_set_drvdata(dev, bl); | |
103 | ||
104 | ep93xxbl_update_status(bl); | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | static int ep93xxbl_remove(struct platform_device *dev) | |
110 | { | |
111 | struct backlight_device *bl = platform_get_drvdata(dev); | |
112 | ||
113 | backlight_device_unregister(bl); | |
114 | platform_set_drvdata(dev, NULL); | |
115 | return 0; | |
116 | } | |
117 | ||
118 | #ifdef CONFIG_PM | |
119 | static int ep93xxbl_suspend(struct platform_device *dev, pm_message_t state) | |
120 | { | |
121 | struct backlight_device *bl = platform_get_drvdata(dev); | |
122 | ||
123 | return ep93xxbl_set(bl, 0); | |
124 | } | |
125 | ||
126 | static int ep93xxbl_resume(struct platform_device *dev) | |
127 | { | |
128 | struct backlight_device *bl = platform_get_drvdata(dev); | |
129 | ||
130 | backlight_update_status(bl); | |
131 | return 0; | |
132 | } | |
133 | #else | |
134 | #define ep93xxbl_suspend NULL | |
135 | #define ep93xxbl_resume NULL | |
136 | #endif | |
137 | ||
138 | static struct platform_driver ep93xxbl_driver = { | |
139 | .driver = { | |
140 | .name = "ep93xx-bl", | |
141 | .owner = THIS_MODULE, | |
142 | }, | |
143 | .probe = ep93xxbl_probe, | |
d1723fa2 | 144 | .remove = ep93xxbl_remove, |
08b3924b HS |
145 | .suspend = ep93xxbl_suspend, |
146 | .resume = ep93xxbl_resume, | |
147 | }; | |
148 | ||
81178e02 | 149 | module_platform_driver(ep93xxbl_driver); |
08b3924b HS |
150 | |
151 | MODULE_DESCRIPTION("EP93xx Backlight Driver"); | |
152 | MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); | |
153 | MODULE_LICENSE("GPL"); | |
154 | MODULE_ALIAS("platform:ep93xx-bl"); |