backlight: Add pcf50633 backlight driver
[sfrench/cifs-2.6.git] / drivers / video / backlight / pcf50633-backlight.c
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");