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
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* ledtrig-gio.c - LED Trigger Based on GPIO events
*
* Copyright 2009 Felipe Balbi <me@felipebalbi.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/leds.h>
#include <linux/slab.h>
#include "../leds.h"
struct gpio_trig_data {
struct led_classdev *led;
unsigned desired_brightness; /* desired brightness when led is on */
unsigned inverted; /* true when gpio is inverted */
unsigned gpio; /* gpio that triggers the leds */
};
static irqreturn_t gpio_trig_irq(int irq, void *_led)
{
struct led_classdev *led = _led;
struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
int tmp;
tmp = gpio_get_value_cansleep(gpio_data->gpio);
if (gpio_data->inverted)
tmp = !tmp;
if (tmp) {
if (gpio_data->desired_brightness)
led_set_brightness_nosleep(gpio_data->led,
gpio_data->desired_brightness);
else
led_set_brightness_nosleep(gpio_data->led, LED_FULL);
} else {
led_set_brightness_nosleep(gpio_data->led, LED_OFF);
}
return IRQ_HANDLED;
}
static ssize_t gpio_trig_brightness_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
return sprintf(buf, "%u\n", gpio_data->desired_brightness);
}
static ssize_t gpio_trig_brightness_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t n)
{
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
unsigned desired_brightness;
int ret;
ret = sscanf(buf, "%u", &desired_brightness);
if (ret < 1 || desired_brightness > 255) {
dev_err(dev, "invalid value\n");
return -EINVAL;
}
gpio_data->desired_brightness = desired_brightness;
return n;
}
static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show,
gpio_trig_brightness_store);
static ssize_t gpio_trig_inverted_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
return sprintf(buf, "%u\n", gpio_data->inverted);
}
static ssize_t gpio_trig_inverted_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t n)
{
struct led_classdev *led = led_trigger_get_led(dev);
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
unsigned long inverted;
int ret;
ret = kstrtoul(buf, 10, &inverted);
if (ret < 0)
return ret;
if (inverted > 1)
return -EINVAL;
gpio_data->inverted = inverted;
/* After inverting, we need to update the LED. */
gpio_trig_irq(0, led);
return n;
}
static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show,
gpio_trig_inverted_store);
static ssize_t gpio_trig_gpio_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
return sprintf(buf, "%u\n", gpio_data->gpio);
}
static ssize_t gpio_trig_gpio_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t n)
{
struct led_classdev *led = led_trigger_get_led(dev);
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
unsigned gpio;
int ret;
ret = sscanf(buf, "%u", &gpio);
if (ret < 1) {
dev_err(dev, "couldn't read gpio number\n");
return -EINVAL;
}
if (gpio_data->gpio == gpio)
return n;
if (!gpio) {
if (gpio_data->gpio != 0)
free_irq(gpio_to_irq(gpio_data->gpio), led);
gpio_data->gpio = 0;
return n;
}
ret = request_threaded_irq(gpio_to_irq(gpio), NULL, gpio_trig_irq,
IRQF_ONESHOT | IRQF_SHARED | IRQF_TRIGGER_RISING
| IRQF_TRIGGER_FALLING, "ledtrig-gpio", led);
if (ret) {
dev_err(dev, "request_irq failed with error %d\n", ret);
} else {
if (gpio_data->gpio != 0)
free_irq(gpio_to_irq(gpio_data->gpio), led);
gpio_data->gpio = gpio;
/* After changing the GPIO, we need to update the LED. */
gpio_trig_irq(0, led);
}
return ret ? ret : n;
}
static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store);
static struct attribute *gpio_trig_attrs[] = {
&dev_attr_desired_brightness.attr,
&dev_attr_inverted.attr,
&dev_attr_gpio.attr,
NULL
};
ATTRIBUTE_GROUPS(gpio_trig);
static int gpio_trig_activate(struct led_classdev *led)
{
struct gpio_trig_data *gpio_data;
gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);
if (!gpio_data)
return -ENOMEM;
gpio_data->led = led;
led_set_trigger_data(led, gpio_data);
return 0;
}
static void gpio_trig_deactivate(struct led_classdev *led)
{
struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
if (gpio_data->gpio != 0)
free_irq(gpio_to_irq(gpio_data->gpio), led);
kfree(gpio_data);
}
static struct led_trigger gpio_led_trigger = {
.name = "gpio",
.activate = gpio_trig_activate,
.deactivate = gpio_trig_deactivate,
.groups = gpio_trig_groups,
};
module_led_trigger(gpio_led_trigger);
MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>");
MODULE_DESCRIPTION("GPIO LED trigger");
MODULE_LICENSE("GPL v2");
|
