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
|
/*
* Backlight emulation LED trigger
*
* Copyright 2008 (C) Rodolfo Giometti <giometti@linux.it>
* Copyright 2008 (C) Eurotech S.p.A. <info@eurotech.it>
*
* 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/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/fb.h>
#include <linux/leds.h>
#include "../leds.h"
#define BLANK 1
#define UNBLANK 0
struct bl_trig_notifier {
struct led_classdev *led;
int brightness;
int old_status;
struct notifier_block notifier;
unsigned invert;
};
static int fb_notifier_callback(struct notifier_block *p,
unsigned long event, void *data)
{
struct bl_trig_notifier *n = container_of(p,
struct bl_trig_notifier, notifier);
struct led_classdev *led = n->led;
struct fb_event *fb_event = data;
int *blank;
int new_status;
/* If we aren't interested in this event, skip it immediately ... */
if (event != FB_EVENT_BLANK)
return 0;
blank = fb_event->data;
new_status = *blank ? BLANK : UNBLANK;
if (new_status == n->old_status)
return 0;
if ((n->old_status == UNBLANK) ^ n->invert) {
n->brightness = led->brightness;
led_set_brightness_nosleep(led, LED_OFF);
} else {
led_set_brightness_nosleep(led, n->brightness);
}
n->old_status = new_status;
return 0;
}
static ssize_t bl_trig_invert_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led = dev_get_drvdata(dev);
struct bl_trig_notifier *n = led->trigger_data;
return sprintf(buf, "%u\n", n->invert);
}
static ssize_t bl_trig_invert_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t num)
{
struct led_classdev *led = dev_get_drvdata(dev);
struct bl_trig_notifier *n = led->trigger_data;
unsigned long invert;
int ret;
ret = kstrtoul(buf, 10, &invert);
if (ret < 0)
return ret;
if (invert > 1)
return -EINVAL;
n->invert = invert;
/* After inverting, we need to update the LED. */
if ((n->old_status == BLANK) ^ n->invert)
led_set_brightness_nosleep(led, LED_OFF);
else
led_set_brightness_nosleep(led, n->brightness);
return num;
}
static DEVICE_ATTR(inverted, 0644, bl_trig_invert_show, bl_trig_invert_store);
static void bl_trig_activate(struct led_classdev *led)
{
int ret;
struct bl_trig_notifier *n;
n = kzalloc(sizeof(struct bl_trig_notifier), GFP_KERNEL);
led->trigger_data = n;
if (!n) {
dev_err(led->dev, "unable to allocate backlight trigger\n");
return;
}
ret = device_create_file(led->dev, &dev_attr_inverted);
if (ret)
goto err_invert;
n->led = led;
n->brightness = led->brightness;
n->old_status = UNBLANK;
n->notifier.notifier_call = fb_notifier_callback;
ret = fb_register_client(&n->notifier);
if (ret)
dev_err(led->dev, "unable to register backlight trigger\n");
led->activated = true;
return;
err_invert:
led->trigger_data = NULL;
kfree(n);
}
static void bl_trig_deactivate(struct led_classdev *led)
{
struct bl_trig_notifier *n =
(struct bl_trig_notifier *) led->trigger_data;
if (led->activated) {
device_remove_file(led->dev, &dev_attr_inverted);
fb_unregister_client(&n->notifier);
kfree(n);
led->activated = false;
}
}
static struct led_trigger bl_led_trigger = {
.name = "backlight",
.activate = bl_trig_activate,
.deactivate = bl_trig_deactivate
};
static int __init bl_trig_init(void)
{
return led_trigger_register(&bl_led_trigger);
}
static void __exit bl_trig_exit(void)
{
led_trigger_unregister(&bl_led_trigger);
}
module_init(bl_trig_init);
module_exit(bl_trig_exit);
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
MODULE_DESCRIPTION("Backlight emulation LED trigger");
MODULE_LICENSE("GPL v2");
|
