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
|
#include <common.h>
#include <driver.h>
#include <linux/list.h>
#include <video/backlight.h>
static LIST_HEAD(backlights);
int backlight_set_brightness(struct backlight_device *bl, int brightness)
{
int ret, step, i, num_steps;
if (brightness > bl->brightness_max)
brightness = bl->brightness_max;
if (brightness == bl->brightness_cur)
return 0;
if (!bl->slew_time_ms) {
ret = bl->brightness_set(bl, brightness);
if (ret)
return ret;
bl->brightness_cur = bl->brightness = brightness;
return 0;
}
if (brightness > bl->brightness_cur)
step = 1;
else
step = -1;
i = bl->brightness_cur;
num_steps = abs(brightness - bl->brightness_cur);
while (1) {
i += step;
ret = bl->brightness_set(bl, i);
if (ret)
return ret;
if (i == brightness)
break;
udelay(bl->slew_time_ms * 1000 / num_steps);
}
bl->brightness_cur = bl->brightness = brightness;
return ret;
}
int backlight_set_brightness_default(struct backlight_device *bl)
{
int ret;
ret = backlight_set_brightness(bl, bl->brightness_default);
return ret;
}
static int backlight_brightness_set(struct param_d *p, void *priv)
{
struct backlight_device *bl = priv;
return backlight_set_brightness(bl, bl->brightness);
}
int backlight_register(struct backlight_device *bl)
{
int ret;
dev_set_name(&bl->dev, "backlight");
bl->dev.id = DEVICE_ID_DYNAMIC;
ret = register_device(&bl->dev);
if (ret)
return ret;
dev_add_param_uint32(&bl->dev, "brightness", backlight_brightness_set,
NULL, &bl->brightness, "%d", bl);
dev_add_param_uint32(&bl->dev, "slew_time_ms", NULL, NULL,
&bl->slew_time_ms, "%d", NULL);
list_add_tail(&bl->list, &backlights);
return ret;
}
struct backlight_device *of_backlight_find(struct device_node *node)
{
struct backlight_device *bl;
list_for_each_entry(bl, &backlights, list)
if (bl->node == node)
return bl;
return NULL;
}
|