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 __devinit 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 ret = -ENXIO;
124 goto out;
125 }
126 data->reg_mode_cntl = res->start;
127 res = platform_get_resource(pdev, IORESOURCE_REG, 1);
128 if (!res) {
129 dev_err(&pdev->dev, "No REG resource for control!\n");
130 ret = -ENXIO;
131 goto out;
132 }
133 data->reg_cntl = res->start;
134
135 data->chip = chip;
136 data->current_brightness = 0;
137
138 memset(&props, 0, sizeof(struct backlight_properties));
139 props.type = BACKLIGHT_RAW;
140 props.max_brightness = MAX_BRIGHTNESS;
141 bl = backlight_device_register("max8925-backlight", &pdev->dev, data,
142 &max8925_backlight_ops, &props);
143 if (IS_ERR(bl)) {
144 dev_err(&pdev->dev, "failed to register backlight\n");
145 ret = PTR_ERR(bl);
146 goto out;
147 }
148 bl->props.brightness = MAX_BRIGHTNESS;
149
150 platform_set_drvdata(pdev, bl);
151
152 value = 0;
153 if (pdata) {
154 if (pdata->lxw_scl)
155 value |= (1 << 7);
156 if (pdata->lxw_freq)
157 value |= (LWX_FREQ(pdata->lxw_freq) << 4);
158 if (pdata->dual_string)
159 value |= (1 << 1);
160 }
161 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value);
162 if (ret < 0)
163 goto out_brt;
164
165 backlight_update_status(bl);
166 return 0;
167out_brt:
168 backlight_device_unregister(bl);
169out:
170 devm_kfree(&pdev->dev, data);
171 return ret;
172}
173
174static int __devexit max8925_backlight_remove(struct platform_device *pdev)
175{
176 struct backlight_device *bl = platform_get_drvdata(pdev);
177
178 backlight_device_unregister(bl);
179 return 0;
180}
181
182static struct platform_driver max8925_backlight_driver = {
183 .driver = {
184 .name = "max8925-backlight",
185 .owner = THIS_MODULE,
186 },
187 .probe = max8925_backlight_probe,
188 .remove = __devexit_p(max8925_backlight_remove),
189};
190
191module_platform_driver(max8925_backlight_driver);
192
193MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
194MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
195MODULE_LICENSE("GPL");
196MODULE_ALIAS("platform:max8925-backlight");