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 */
pcf50633_bl_set_brightness_limit(struct pcf50633 * pcf,unsigned int limit)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
pcf50633_bl_update_status(struct backlight_device * bl)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
pcf50633_bl_get_brightness(struct backlight_device * bl)90 static int pcf50633_bl_get_brightness(struct backlight_device *bl)
91 {
92 struct pcf50633_bl *pcf_bl = bl_get_data(bl);
93
94 return pcf_bl->brightness;
95 }
96
97 static const struct backlight_ops pcf50633_bl_ops = {
98 .get_brightness = pcf50633_bl_get_brightness,
99 .update_status = pcf50633_bl_update_status,
100 .options = BL_CORE_SUSPENDRESUME,
101 };
102
pcf50633_bl_probe(struct platform_device * pdev)103 static int pcf50633_bl_probe(struct platform_device *pdev)
104 {
105 struct pcf50633_bl *pcf_bl;
106 struct device *parent = pdev->dev.parent;
107 struct pcf50633_platform_data *pcf50633_data = dev_get_platdata(parent);
108 struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data;
109 struct backlight_properties bl_props;
110
111 pcf_bl = devm_kzalloc(&pdev->dev, sizeof(*pcf_bl), GFP_KERNEL);
112 if (!pcf_bl)
113 return -ENOMEM;
114
115 memset(&bl_props, 0, sizeof(bl_props));
116 bl_props.type = BACKLIGHT_RAW;
117 bl_props.max_brightness = 0x3f;
118 bl_props.power = FB_BLANK_UNBLANK;
119
120 if (pdata) {
121 bl_props.brightness = pdata->default_brightness;
122 pcf_bl->brightness_limit = pdata->default_brightness_limit;
123 } else {
124 bl_props.brightness = 0x3f;
125 pcf_bl->brightness_limit = 0x3f;
126 }
127
128 pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent);
129
130 pcf_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,
131 &pdev->dev, pcf_bl,
132 &pcf50633_bl_ops, &bl_props);
133
134 if (IS_ERR(pcf_bl->bl))
135 return PTR_ERR(pcf_bl->bl);
136
137 platform_set_drvdata(pdev, pcf_bl);
138
139 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);
140
141 /*
142 * Should be different from bl_props.brightness, so we do not exit
143 * update_status early the first time it's called
144 */
145 pcf_bl->brightness = pcf_bl->bl->props.brightness + 1;
146
147 backlight_update_status(pcf_bl->bl);
148
149 return 0;
150 }
151
152 static struct platform_driver pcf50633_bl_driver = {
153 .probe = pcf50633_bl_probe,
154 .driver = {
155 .name = "pcf50633-backlight",
156 },
157 };
158
159 module_platform_driver(pcf50633_bl_driver);
160
161 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
162 MODULE_DESCRIPTION("PCF50633 backlight driver");
163 MODULE_LICENSE("GPL");
164 MODULE_ALIAS("platform:pcf50633-backlight");
165