tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Backlight driver for Maxim MAX8925
3 *
4 * Copyright (C) 2009 Marvell International Ltd.
5 * Haojian Zhuang <haojian.zhuang@marvell.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/platform_device.h>
15#include <linux/fb.h>
16#include <linux/i2c.h>
17#include <linux/backlight.h>
18#include <linux/mfd/max8925.h>
19#include <linux/slab.h>
20#include <linux/module.h>
21
22#define MAX_BRIGHTNESS (0xff)
23#define MIN_BRIGHTNESS (0)
24
25#define LWX_FREQ(x) (((x - 601) / 100) & 0x7)
26
27struct max8925_backlight_data {
28 struct max8925_chip *chip;
29
30 int current_brightness;
31 int reg_mode_cntl;
32 int reg_cntl;
33};
34
35static int max8925_backlight_set(struct backlight_device *bl, int brightness)
36{
37 struct max8925_backlight_data *data = bl_get_data(bl);
38 struct max8925_chip *chip = data->chip;
39 unsigned char value;
40 int ret;
41
42 if (brightness > MAX_BRIGHTNESS)
43 value = MAX_BRIGHTNESS;
44 else
45 value = brightness;
46
47 ret = max8925_reg_write(chip->i2c, data->reg_cntl, value);
48 if (ret < 0)
49 goto out;
50
51 if (!data->current_brightness && brightness)
52 /* enable WLED output */
53 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1);
54 else if (!brightness)
55 /* disable WLED output */
56 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0);
57 if (ret < 0)
58 goto out;
59 dev_dbg(chip->dev, "set brightness %d\n", value);
60 data->current_brightness = value;
61 return 0;
62out:
63 dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
64 value, ret);
65 return ret;
66}
67
68static int max8925_backlight_update_status(struct backlight_device *bl)
69{
70 int brightness = bl->props.brightness;
71
72 if (bl->props.power != FB_BLANK_UNBLANK)
73 brightness = 0;
74
75 if (bl->props.fb_blank != FB_BLANK_UNBLANK)
76 brightness = 0;
77
78 if (bl->props.state & BL_CORE_SUSPENDED)
79 brightness = 0;
80
81 return max8925_backlight_set(bl, brightness);
82}
83
84static int max8925_backlight_get_brightness(struct backlight_device *bl)
85{
86 struct max8925_backlight_data *data = bl_get_data(bl);
87 struct max8925_chip *chip = data->chip;
88 int ret;
89
90 ret = max8925_reg_read(chip->i2c, data->reg_cntl);
91 if (ret < 0)
92 return -EINVAL;
93 data->current_brightness = ret;
94 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
95 return ret;
96}
97
98static const struct backlight_ops max8925_backlight_ops = {
99 .options = BL_CORE_SUSPENDRESUME,
100 .update_status = max8925_backlight_update_status,
101 .get_brightness = max8925_backlight_get_brightness,
102};
103
104static int max8925_backlight_probe(struct platform_device *pdev)
105{
106 struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
107 struct max8925_backlight_pdata *pdata = pdev->dev.platform_data;
108 struct max8925_backlight_data *data;
109 struct backlight_device *bl;
110 struct backlight_properties props;
111 struct resource *res;
112 unsigned char value;
113 int ret = 0;
114
115 data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data),
116 GFP_KERNEL);
117 if (data == NULL)
118 return -ENOMEM;
119
120 res = platform_get_resource(pdev, IORESOURCE_REG, 0);
121 if (!res) {
122 dev_err(&pdev->dev, "No REG resource for mode control!\n");
123 return -ENXIO;
124 }
125 data->reg_mode_cntl = res->start;
126 res = platform_get_resource(pdev, IORESOURCE_REG, 1);
127 if (!res) {
128 dev_err(&pdev->dev, "No REG resource for control!\n");
129 return -ENXIO;
130 }
131 data->reg_cntl = res->start;
132
133 data->chip = chip;
134 data->current_brightness = 0;
135
136 memset(&props, 0, sizeof(struct backlight_properties));
137 props.type = BACKLIGHT_RAW;
138 props.max_brightness = MAX_BRIGHTNESS;
139 bl = backlight_device_register("max8925-backlight", &pdev->dev, data,
140 &max8925_backlight_ops, &props);
141 if (IS_ERR(bl)) {
142 dev_err(&pdev->dev, "failed to register backlight\n");
143 return PTR_ERR(bl);
144 }
145 bl->props.brightness = MAX_BRIGHTNESS;
146
147 platform_set_drvdata(pdev, bl);
148
149 value = 0;
150 if (pdata) {
151 if (pdata->lxw_scl)
152 value |= (1 << 7);
153 if (pdata->lxw_freq)
154 value |= (LWX_FREQ(pdata->lxw_freq) << 4);
155 if (pdata->dual_string)
156 value |= (1 << 1);
157 }
158 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value);
159 if (ret < 0)
160 goto out_brt;
161
162 backlight_update_status(bl);
163 return 0;
164out_brt:
165 backlight_device_unregister(bl);
166 return ret;
167}
168
169static int max8925_backlight_remove(struct platform_device *pdev)
170{
171 struct backlight_device *bl = platform_get_drvdata(pdev);
172
173 backlight_device_unregister(bl);
174 return 0;
175}
176
177static struct platform_driver max8925_backlight_driver = {
178 .driver = {
179 .name = "max8925-backlight",
180 .owner = THIS_MODULE,
181 },
182 .probe = max8925_backlight_probe,
183 .remove = max8925_backlight_remove,
184};
185
186module_platform_driver(max8925_backlight_driver);
187
188MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
189MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
190MODULE_LICENSE("GPL");
191MODULE_ALIAS("platform:max8925-backlight");