summaryrefslogtreecommitdiff
path: root/drivers/video/backlight/pcf50633-backlight.c
blob: 6ed76be18f1943e55fd7ad405c490a8749833358 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
/*
 *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
 *      PCF50633 backlight device driver
 *
 *  This program is free software; you can redistribute	 it and/or modify it
 *  under  the terms of	 the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the	License, or (at your
 *  option) any later version.
 *
 *  You should have received a copy of the  GNU General Public License along
 *  with this program; if not, write  to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>

#include <linux/backlight.h>
#include <linux/fb.h>

#include <linux/mfd/pcf50633/core.h>
#include <linux/mfd/pcf50633/backlight.h>

struct pcf50633_bl {
	struct pcf50633 *pcf;
	struct backlight_device *bl;

	unsigned int brightness;
	unsigned int brightness_limit;
};

/*
 * pcf50633_bl_set_brightness_limit
 *
 * Update the brightness limit for the pc50633 backlight. The actual brightness
 * will not go above the limit. This is useful to limit power drain for example
 * on low battery.
 *
 * @dev: Pointer to a pcf50633 device
 * @limit: The brightness limit. Valid values are 0-63
 */
int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit)
{
	struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev);

	if (!pcf_bl)
		return -ENODEV;

	pcf_bl->brightness_limit = limit & 0x3f;
	backlight_update_status(pcf_bl->bl);

	return 0;
}

static int pcf50633_bl_update_status(struct backlight_device *bl)
{
	struct pcf50633_bl *pcf_bl = bl_get_data(bl);
	unsigned int new_brightness;


	if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) ||
		bl->props.power != FB_BLANK_UNBLANK)
		new_brightness = 0;
	else if (bl->props.brightness < pcf_bl->brightness_limit)
		new_brightness = bl->props.brightness;
	else
		new_brightness = pcf_bl->brightness_limit;


	if (pcf_bl->brightness == new_brightness)
		return 0;

	if (new_brightness) {
		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT,
					new_brightness);
		if (!pcf_bl->brightness)
			pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1);
	} else {
		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0);
	}

	pcf_bl->brightness = new_brightness;

	return 0;
}

static int pcf50633_bl_get_brightness(struct backlight_device *bl)
{
	struct pcf50633_bl *pcf_bl = bl_get_data(bl);
	return pcf_bl->brightness;
}

static const struct backlight_ops pcf50633_bl_ops = {
	.get_brightness = pcf50633_bl_get_brightness,
	.update_status	= pcf50633_bl_update_status,
	.options	= BL_CORE_SUSPENDRESUME,
};

static int pcf50633_bl_probe(struct platform_device *pdev)
{
	struct pcf50633_bl *pcf_bl;
	struct device *parent = pdev->dev.parent;
	struct pcf50633_platform_data *pcf50633_data = parent->platform_data;
	struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data;
	struct backlight_properties bl_props;

	pcf_bl = devm_kzalloc(&pdev->dev, sizeof(*pcf_bl), GFP_KERNEL);
	if (!pcf_bl)
		return -ENOMEM;

	memset(&bl_props, 0, sizeof(bl_props));
	bl_props.type = BACKLIGHT_RAW;
	bl_props.max_brightness = 0x3f;
	bl_props.power = FB_BLANK_UNBLANK;

	if (pdata) {
		bl_props.brightness = pdata->default_brightness;
		pcf_bl->brightness_limit = pdata->default_brightness_limit;
	} else {
		bl_props.brightness = 0x3f;
		pcf_bl->brightness_limit = 0x3f;
	}

	pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent);

	pcf_bl->bl = backlight_device_register(pdev->name, &pdev->dev, pcf_bl,
						&pcf50633_bl_ops, &bl_props);

	if (IS_ERR(pcf_bl->bl))
		return PTR_ERR(pcf_bl->bl);

	platform_set_drvdata(pdev, pcf_bl);

	pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);

	/*
	 * Should be different from bl_props.brightness, so we do not exit
	 * update_status early the first time it's called
	 */
	pcf_bl->brightness = pcf_bl->bl->props.brightness + 1;

	backlight_update_status(pcf_bl->bl);

	return 0;
}

static int pcf50633_bl_remove(struct platform_device *pdev)
{
	struct pcf50633_bl *pcf_bl = platform_get_drvdata(pdev);

	backlight_device_unregister(pcf_bl->bl);

	return 0;
}

static struct platform_driver pcf50633_bl_driver = {
	.probe =	pcf50633_bl_probe,
	.remove =	pcf50633_bl_remove,
	.driver = {
		.name = "pcf50633-backlight",
	},
};

module_platform_driver(pcf50633_bl_driver);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("PCF50633 backlight driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pcf50633-backlight");