blob: a247ae63374f161973785a3cb3675b082947cbec [file] [log] [blame]
Felipe Balbi17354bf2009-02-17 13:18:11 +02001/*
2 * ledtrig-gio.c - LED Trigger Based on GPIO events
3 *
4 * Copyright 2009 Felipe Balbi <me@felipebalbi.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/gpio.h>
16#include <linux/interrupt.h>
17#include <linux/workqueue.h>
18#include <linux/leds.h>
19#include "leds.h"
20
21struct gpio_trig_data {
22 struct led_classdev *led;
23 struct work_struct work;
24
25 unsigned desired_brightness; /* desired brightness when led is on */
26 unsigned inverted; /* true when gpio is inverted */
27 unsigned gpio; /* gpio that triggers the leds */
28};
29
30static irqreturn_t gpio_trig_irq(int irq, void *_led)
31{
32 struct led_classdev *led = _led;
33 struct gpio_trig_data *gpio_data = led->trigger_data;
34
35 /* just schedule_work since gpio_get_value can sleep */
36 schedule_work(&gpio_data->work);
37
38 return IRQ_HANDLED;
39};
40
41static void gpio_trig_work(struct work_struct *work)
42{
43 struct gpio_trig_data *gpio_data = container_of(work,
44 struct gpio_trig_data, work);
45 int tmp;
46
47 if (!gpio_data->gpio)
48 return;
49
50 tmp = gpio_get_value(gpio_data->gpio);
51 if (gpio_data->inverted)
52 tmp = !tmp;
53
54 if (tmp) {
55 if (gpio_data->desired_brightness)
56 led_set_brightness(gpio_data->led,
57 gpio_data->desired_brightness);
58 else
59 led_set_brightness(gpio_data->led, LED_FULL);
60 } else {
61 led_set_brightness(gpio_data->led, LED_OFF);
62 }
63}
64
65static ssize_t gpio_trig_brightness_show(struct device *dev,
66 struct device_attribute *attr, char *buf)
67{
68 struct led_classdev *led = dev_get_drvdata(dev);
69 struct gpio_trig_data *gpio_data = led->trigger_data;
70
71 return sprintf(buf, "%u\n", gpio_data->desired_brightness);
72}
73
74static ssize_t gpio_trig_brightness_store(struct device *dev,
75 struct device_attribute *attr, const char *buf, size_t n)
76{
77 struct led_classdev *led = dev_get_drvdata(dev);
78 struct gpio_trig_data *gpio_data = led->trigger_data;
79 unsigned desired_brightness;
80 int ret;
81
82 ret = sscanf(buf, "%u", &desired_brightness);
83 if (ret < 1 || desired_brightness > 255) {
84 dev_err(dev, "invalid value\n");
85 return -EINVAL;
86 }
87
88 gpio_data->desired_brightness = desired_brightness;
89
90 return n;
91}
92static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show,
93 gpio_trig_brightness_store);
94
95static ssize_t gpio_trig_inverted_show(struct device *dev,
96 struct device_attribute *attr, char *buf)
97{
98 struct led_classdev *led = dev_get_drvdata(dev);
99 struct gpio_trig_data *gpio_data = led->trigger_data;
100
101 return sprintf(buf, "%s\n", gpio_data->inverted ? "yes" : "no");
102}
103
104static ssize_t gpio_trig_inverted_store(struct device *dev,
105 struct device_attribute *attr, const char *buf, size_t n)
106{
107 struct led_classdev *led = dev_get_drvdata(dev);
108 struct gpio_trig_data *gpio_data = led->trigger_data;
109 unsigned inverted;
110 int ret;
111
112 ret = sscanf(buf, "%u", &inverted);
113 if (ret < 1) {
114 dev_err(dev, "invalid value\n");
115 return -EINVAL;
116 }
117
118 gpio_data->inverted = !!inverted;
119
120 return n;
121}
122static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show,
123 gpio_trig_inverted_store);
124
125static ssize_t gpio_trig_gpio_show(struct device *dev,
126 struct device_attribute *attr, char *buf)
127{
128 struct led_classdev *led = dev_get_drvdata(dev);
129 struct gpio_trig_data *gpio_data = led->trigger_data;
130
131 return sprintf(buf, "%u\n", gpio_data->gpio);
132}
133
134static ssize_t gpio_trig_gpio_store(struct device *dev,
135 struct device_attribute *attr, const char *buf, size_t n)
136{
137 struct led_classdev *led = dev_get_drvdata(dev);
138 struct gpio_trig_data *gpio_data = led->trigger_data;
139 unsigned gpio;
140 int ret;
141
142 ret = sscanf(buf, "%u", &gpio);
143 if (ret < 1) {
144 dev_err(dev, "couldn't read gpio number\n");
145 flush_work(&gpio_data->work);
146 return -EINVAL;
147 }
148
149 if (!gpio) {
150 free_irq(gpio_to_irq(gpio_data->gpio), led);
151 return n;
152 }
153
154 if (gpio_data->gpio > 0 && gpio_data->gpio != gpio)
155 free_irq(gpio_to_irq(gpio_data->gpio), led);
156
157 gpio_data->gpio = gpio;
158 ret = request_irq(gpio_to_irq(gpio), gpio_trig_irq,
159 IRQF_SHARED | IRQF_TRIGGER_RISING
160 | IRQF_TRIGGER_FALLING, "ledtrig-gpio", led);
161 if (ret)
162 dev_err(dev, "request_irq failed with error %d\n", ret);
163
164 return ret ? ret : n;
165}
166static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store);
167
168static void gpio_trig_activate(struct led_classdev *led)
169{
170 struct gpio_trig_data *gpio_data;
171 int ret;
172
173 gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);
174 if (!gpio_data)
175 return;
176
177 ret = device_create_file(led->dev, &dev_attr_gpio);
178 if (ret)
179 goto err_gpio;
180
181 ret = device_create_file(led->dev, &dev_attr_inverted);
182 if (ret)
183 goto err_inverted;
184
185 ret = device_create_file(led->dev, &dev_attr_desired_brightness);
186 if (ret)
187 goto err_brightness;
188
189 gpio_data->led = led;
190 led->trigger_data = gpio_data;
191 INIT_WORK(&gpio_data->work, gpio_trig_work);
192
193 return;
194
195err_brightness:
196 device_remove_file(led->dev, &dev_attr_inverted);
197
198err_inverted:
199 device_remove_file(led->dev, &dev_attr_gpio);
200
201err_gpio:
202 kfree(gpio_data);
203}
204
205static void gpio_trig_deactivate(struct led_classdev *led)
206{
207 struct gpio_trig_data *gpio_data = led->trigger_data;
208
209 if (gpio_data) {
210 device_remove_file(led->dev, &dev_attr_gpio);
211 device_remove_file(led->dev, &dev_attr_inverted);
212 device_remove_file(led->dev, &dev_attr_desired_brightness);
213 flush_work(&gpio_data->work);
214 free_irq(gpio_to_irq(gpio_data->gpio),led);
215 kfree(gpio_data);
216 }
217}
218
219static struct led_trigger gpio_led_trigger = {
220 .name = "gpio",
221 .activate = gpio_trig_activate,
222 .deactivate = gpio_trig_deactivate,
223};
224
225static int __init gpio_trig_init(void)
226{
227 return led_trigger_register(&gpio_led_trigger);
228}
229module_init(gpio_trig_init);
230
231static void __exit gpio_trig_exit(void)
232{
233 led_trigger_unregister(&gpio_led_trigger);
234}
235module_exit(gpio_trig_exit);
236
237MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>");
238MODULE_DESCRIPTION("GPIO LED trigger");
239MODULE_LICENSE("GPL");