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
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
|
/*
* Backlight driver for Maxim MAX8925
*
* Copyright (C) 2009 Marvell International Ltd.
* Haojian Zhuang <haojian.zhuang@marvell.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/fb.h>
#include <linux/i2c.h>
#include <linux/backlight.h>
#include <linux/mfd/max8925.h>
#include <linux/slab.h>
#include <linux/module.h>
#define MAX_BRIGHTNESS (0xff)
#define MIN_BRIGHTNESS (0)
#define LWX_FREQ(x) (((x - 601) / 100) & 0x7)
struct max8925_backlight_data {
struct max8925_chip *chip;
int current_brightness;
int reg_mode_cntl;
int reg_cntl;
};
static int max8925_backlight_set(struct backlight_device *bl, int brightness)
{
struct max8925_backlight_data *data = bl_get_data(bl);
struct max8925_chip *chip = data->chip;
unsigned char value;
int ret;
if (brightness > MAX_BRIGHTNESS)
value = MAX_BRIGHTNESS;
else
value = brightness;
ret = max8925_reg_write(chip->i2c, data->reg_cntl, value);
if (ret < 0)
goto out;
if (!data->current_brightness && brightness)
/* enable WLED output */
ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1);
else if (!brightness)
/* disable WLED output */
ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0);
if (ret < 0)
goto out;
dev_dbg(chip->dev, "set brightness %d\n", value);
data->current_brightness = value;
return 0;
out:
dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
value, ret);
return ret;
}
static int max8925_backlight_update_status(struct backlight_device *bl)
{
int brightness = bl->props.brightness;
if (bl->props.power != FB_BLANK_UNBLANK)
brightness = 0;
if (bl->props.fb_blank != FB_BLANK_UNBLANK)
brightness = 0;
if (bl->props.state & BL_CORE_SUSPENDED)
brightness = 0;
return max8925_backlight_set(bl, brightness);
}
static int max8925_backlight_get_brightness(struct backlight_device *bl)
{
struct max8925_backlight_data *data = bl_get_data(bl);
struct max8925_chip *chip = data->chip;
int ret;
ret = max8925_reg_read(chip->i2c, data->reg_cntl);
if (ret < 0)
return -EINVAL;
data->current_brightness = ret;
dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
return ret;
}
static const struct backlight_ops max8925_backlight_ops = {
.options = BL_CORE_SUSPENDRESUME,
.update_status = max8925_backlight_update_status,
.get_brightness = max8925_backlight_get_brightness,
};
static void max8925_backlight_dt_init(struct platform_device *pdev)
{
struct device_node *nproot = pdev->dev.parent->of_node, *np;
struct max8925_backlight_pdata *pdata;
u32 val;
if (!nproot || !IS_ENABLED(CONFIG_OF))
return;
pdata = devm_kzalloc(&pdev->dev,
sizeof(struct max8925_backlight_pdata),
GFP_KERNEL);
if (!pdata)
return;
np = of_get_child_by_name(nproot, "backlight");
if (!np) {
dev_err(&pdev->dev, "failed to find backlight node\n");
return;
}
if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val))
pdata->dual_string = val;
of_node_put(np);
pdev->dev.platform_data = pdata;
}
static int max8925_backlight_probe(struct platform_device *pdev)
{
struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
struct max8925_backlight_pdata *pdata;
struct max8925_backlight_data *data;
struct backlight_device *bl;
struct backlight_properties props;
struct resource *res;
unsigned char value;
int ret = 0;
data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data),
GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_REG, 0);
if (!res) {
dev_err(&pdev->dev, "No REG resource for mode control!\n");
return -ENXIO;
}
data->reg_mode_cntl = res->start;
res = platform_get_resource(pdev, IORESOURCE_REG, 1);
if (!res) {
dev_err(&pdev->dev, "No REG resource for control!\n");
return -ENXIO;
}
data->reg_cntl = res->start;
data->chip = chip;
data->current_brightness = 0;
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_RAW;
props.max_brightness = MAX_BRIGHTNESS;
bl = devm_backlight_device_register(&pdev->dev, "max8925-backlight",
&pdev->dev, data,
&max8925_backlight_ops, &props);
if (IS_ERR(bl)) {
dev_err(&pdev->dev, "failed to register backlight\n");
return PTR_ERR(bl);
}
bl->props.brightness = MAX_BRIGHTNESS;
platform_set_drvdata(pdev, bl);
value = 0;
if (!pdev->dev.platform_data)
max8925_backlight_dt_init(pdev);
pdata = pdev->dev.platform_data;
if (pdata) {
if (pdata->lxw_scl)
value |= (1 << 7);
if (pdata->lxw_freq)
value |= (LWX_FREQ(pdata->lxw_freq) << 4);
if (pdata->dual_string)
value |= (1 << 1);
}
ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value);
if (ret < 0)
return ret;
backlight_update_status(bl);
return 0;
}
static struct platform_driver max8925_backlight_driver = {
.driver = {
.name = "max8925-backlight",
},
.probe = max8925_backlight_probe,
};
module_platform_driver(max8925_backlight_driver);
MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:max8925-backlight");
|
