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2ddfd12f LPC |
1 | /* |
2 | * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de> | |
3 | * PCF50633 backlight device driver | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License as published by the | |
7 | * Free Software Foundation; either version 2 of the License, or (at your | |
8 | * option) any later version. | |
9 | * | |
10 | * You should have received a copy of the GNU General Public License along | |
11 | * with this program; if not, write to the Free Software Foundation, Inc., | |
12 | * 675 Mass Ave, Cambridge, MA 02139, USA. | |
13 | * | |
14 | */ | |
15 | ||
16 | #include <linux/kernel.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/platform_device.h> | |
20 | ||
21 | #include <linux/backlight.h> | |
22 | #include <linux/fb.h> | |
23 | ||
24 | #include <linux/mfd/pcf50633/core.h> | |
25 | #include <linux/mfd/pcf50633/backlight.h> | |
26 | ||
27 | struct pcf50633_bl { | |
28 | struct pcf50633 *pcf; | |
29 | struct backlight_device *bl; | |
30 | ||
31 | unsigned int brightness; | |
32 | unsigned int brightness_limit; | |
33 | }; | |
34 | ||
35 | /* | |
36 | * pcf50633_bl_set_brightness_limit | |
37 | * | |
38 | * Update the brightness limit for the pc50633 backlight. The actual brightness | |
39 | * will not go above the limit. This is useful to limit power drain for example | |
40 | * on low battery. | |
41 | * | |
42 | * @dev: Pointer to a pcf50633 device | |
43 | * @limit: The brightness limit. Valid values are 0-63 | |
44 | */ | |
45 | int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit) | |
46 | { | |
47 | struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev); | |
48 | ||
49 | if (!pcf_bl) | |
50 | return -ENODEV; | |
51 | ||
52 | pcf_bl->brightness_limit = limit & 0x3f; | |
53 | backlight_update_status(pcf_bl->bl); | |
54 | ||
55 | return 0; | |
56 | } | |
57 | ||
58 | static int pcf50633_bl_update_status(struct backlight_device *bl) | |
59 | { | |
60 | struct pcf50633_bl *pcf_bl = bl_get_data(bl); | |
61 | unsigned int new_brightness; | |
62 | ||
63 | ||
64 | if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) || | |
65 | bl->props.power != FB_BLANK_UNBLANK) | |
66 | new_brightness = 0; | |
67 | else if (bl->props.brightness < pcf_bl->brightness_limit) | |
68 | new_brightness = bl->props.brightness; | |
69 | else | |
70 | new_brightness = pcf_bl->brightness_limit; | |
71 | ||
72 | ||
73 | if (pcf_bl->brightness == new_brightness) | |
74 | return 0; | |
75 | ||
76 | if (new_brightness) { | |
77 | pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT, | |
78 | new_brightness); | |
79 | if (!pcf_bl->brightness) | |
80 | pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1); | |
81 | } else { | |
82 | pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0); | |
83 | } | |
84 | ||
85 | pcf_bl->brightness = new_brightness; | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
90 | static int pcf50633_bl_get_brightness(struct backlight_device *bl) | |
91 | { | |
92 | struct pcf50633_bl *pcf_bl = bl_get_data(bl); | |
93 | return pcf_bl->brightness; | |
94 | } | |
95 | ||
96 | static const struct backlight_ops pcf50633_bl_ops = { | |
97 | .get_brightness = pcf50633_bl_get_brightness, | |
98 | .update_status = pcf50633_bl_update_status, | |
99 | .options = BL_CORE_SUSPENDRESUME, | |
100 | }; | |
101 | ||
102 | static int __devinit pcf50633_bl_probe(struct platform_device *pdev) | |
103 | { | |
104 | int ret; | |
105 | struct pcf50633_bl *pcf_bl; | |
106 | struct device *parent = pdev->dev.parent; | |
107 | struct pcf50633_platform_data *pcf50633_data = parent->platform_data; | |
108 | struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data; | |
109 | struct backlight_properties bl_props; | |
110 | ||
111 | pcf_bl = kzalloc(sizeof(*pcf_bl), GFP_KERNEL); | |
112 | if (!pcf_bl) | |
113 | return -ENOMEM; | |
114 | ||
115 | bl_props.max_brightness = 0x3f; | |
116 | bl_props.power = FB_BLANK_UNBLANK; | |
117 | ||
118 | if (pdata) { | |
119 | bl_props.brightness = pdata->default_brightness; | |
120 | pcf_bl->brightness_limit = pdata->default_brightness_limit; | |
121 | } else { | |
122 | bl_props.brightness = 0x3f; | |
123 | pcf_bl->brightness_limit = 0x3f; | |
124 | } | |
125 | ||
126 | pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent); | |
127 | ||
128 | pcf_bl->bl = backlight_device_register(pdev->name, &pdev->dev, pcf_bl, | |
129 | &pcf50633_bl_ops, &bl_props); | |
130 | ||
131 | if (IS_ERR(pcf_bl->bl)) { | |
132 | ret = PTR_ERR(pcf_bl->bl); | |
133 | goto err_free; | |
134 | } | |
135 | ||
136 | platform_set_drvdata(pdev, pcf_bl); | |
137 | ||
138 | pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time); | |
139 | ||
140 | /* Should be different from bl_props.brightness, so we do not exit | |
141 | * update_status early the first time it's called */ | |
142 | pcf_bl->brightness = pcf_bl->bl->props.brightness + 1; | |
143 | ||
144 | backlight_update_status(pcf_bl->bl); | |
145 | ||
146 | return 0; | |
147 | ||
148 | err_free: | |
149 | kfree(pcf_bl); | |
150 | ||
151 | return ret; | |
152 | } | |
153 | ||
154 | static int __devexit pcf50633_bl_remove(struct platform_device *pdev) | |
155 | { | |
156 | struct pcf50633_bl *pcf_bl = platform_get_drvdata(pdev); | |
157 | ||
158 | backlight_device_unregister(pcf_bl->bl); | |
159 | ||
160 | platform_set_drvdata(pdev, NULL); | |
161 | ||
162 | kfree(pcf_bl); | |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
167 | static struct platform_driver pcf50633_bl_driver = { | |
168 | .probe = pcf50633_bl_probe, | |
169 | .remove = __devexit_p(pcf50633_bl_remove), | |
170 | .driver = { | |
171 | .name = "pcf50633-backlight", | |
172 | }, | |
173 | }; | |
174 | ||
175 | static int __init pcf50633_bl_init(void) | |
176 | { | |
177 | return platform_driver_register(&pcf50633_bl_driver); | |
178 | } | |
179 | module_init(pcf50633_bl_init); | |
180 | ||
181 | static void __exit pcf50633_bl_exit(void) | |
182 | { | |
183 | platform_driver_unregister(&pcf50633_bl_driver); | |
184 | } | |
185 | module_exit(pcf50633_bl_exit); | |
186 | ||
187 | MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); | |
188 | MODULE_DESCRIPTION("PCF50633 backlight driver"); | |
189 | MODULE_LICENSE("GPL"); | |
190 | MODULE_ALIAS("platform:pcf50633-backlight"); |