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17354bfe FB |
1 | /* |
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 | ||
21 | struct 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 | ||
30 | static 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 | ||
41 | static 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 | ||
65 | static 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 | ||
74 | static 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 | } | |
92 | static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show, | |
93 | gpio_trig_brightness_store); | |
94 | ||
95 | static 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 | ||
104 | static 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 | } | |
122 | static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show, | |
123 | gpio_trig_inverted_store); | |
124 | ||
125 | static 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 | ||
134 | static 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 | ||
48cccd26 TLSC |
149 | if (gpio_data->gpio == gpio) |
150 | return n; | |
151 | ||
17354bfe | 152 | if (!gpio) { |
48cccd26 TLSC |
153 | if (gpio_data->gpio != 0) |
154 | free_irq(gpio_to_irq(gpio_data->gpio), led); | |
155 | gpio_data->gpio = 0; | |
17354bfe FB |
156 | return n; |
157 | } | |
158 | ||
17354bfe FB |
159 | ret = request_irq(gpio_to_irq(gpio), gpio_trig_irq, |
160 | IRQF_SHARED | IRQF_TRIGGER_RISING | |
161 | | IRQF_TRIGGER_FALLING, "ledtrig-gpio", led); | |
48cccd26 | 162 | if (ret) { |
17354bfe | 163 | dev_err(dev, "request_irq failed with error %d\n", ret); |
48cccd26 TLSC |
164 | } else { |
165 | if (gpio_data->gpio != 0) | |
166 | free_irq(gpio_to_irq(gpio_data->gpio), led); | |
167 | gpio_data->gpio = gpio; | |
168 | } | |
17354bfe FB |
169 | |
170 | return ret ? ret : n; | |
171 | } | |
172 | static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store); | |
173 | ||
174 | static void gpio_trig_activate(struct led_classdev *led) | |
175 | { | |
176 | struct gpio_trig_data *gpio_data; | |
177 | int ret; | |
178 | ||
179 | gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL); | |
180 | if (!gpio_data) | |
181 | return; | |
182 | ||
183 | ret = device_create_file(led->dev, &dev_attr_gpio); | |
184 | if (ret) | |
185 | goto err_gpio; | |
186 | ||
187 | ret = device_create_file(led->dev, &dev_attr_inverted); | |
188 | if (ret) | |
189 | goto err_inverted; | |
190 | ||
191 | ret = device_create_file(led->dev, &dev_attr_desired_brightness); | |
192 | if (ret) | |
193 | goto err_brightness; | |
194 | ||
195 | gpio_data->led = led; | |
196 | led->trigger_data = gpio_data; | |
197 | INIT_WORK(&gpio_data->work, gpio_trig_work); | |
198 | ||
199 | return; | |
200 | ||
201 | err_brightness: | |
202 | device_remove_file(led->dev, &dev_attr_inverted); | |
203 | ||
204 | err_inverted: | |
205 | device_remove_file(led->dev, &dev_attr_gpio); | |
206 | ||
207 | err_gpio: | |
208 | kfree(gpio_data); | |
209 | } | |
210 | ||
211 | static void gpio_trig_deactivate(struct led_classdev *led) | |
212 | { | |
213 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
214 | ||
215 | if (gpio_data) { | |
216 | device_remove_file(led->dev, &dev_attr_gpio); | |
217 | device_remove_file(led->dev, &dev_attr_inverted); | |
218 | device_remove_file(led->dev, &dev_attr_desired_brightness); | |
219 | flush_work(&gpio_data->work); | |
48cccd26 TLSC |
220 | if (gpio_data->gpio != 0) |
221 | free_irq(gpio_to_irq(gpio_data->gpio), led); | |
17354bfe FB |
222 | kfree(gpio_data); |
223 | } | |
224 | } | |
225 | ||
226 | static struct led_trigger gpio_led_trigger = { | |
227 | .name = "gpio", | |
228 | .activate = gpio_trig_activate, | |
229 | .deactivate = gpio_trig_deactivate, | |
230 | }; | |
231 | ||
232 | static int __init gpio_trig_init(void) | |
233 | { | |
234 | return led_trigger_register(&gpio_led_trigger); | |
235 | } | |
236 | module_init(gpio_trig_init); | |
237 | ||
238 | static void __exit gpio_trig_exit(void) | |
239 | { | |
240 | led_trigger_unregister(&gpio_led_trigger); | |
241 | } | |
242 | module_exit(gpio_trig_exit); | |
243 | ||
244 | MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>"); | |
245 | MODULE_DESCRIPTION("GPIO LED trigger"); | |
246 | MODULE_LICENSE("GPL"); |