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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> | |
5a0e3ad6 | 19 | #include <linux/slab.h> |
17354bfe FB |
20 | #include "leds.h" |
21 | ||
22 | struct gpio_trig_data { | |
23 | struct led_classdev *led; | |
24 | struct work_struct work; | |
25 | ||
26 | unsigned desired_brightness; /* desired brightness when led is on */ | |
27 | unsigned inverted; /* true when gpio is inverted */ | |
28 | unsigned gpio; /* gpio that triggers the leds */ | |
29 | }; | |
30 | ||
31 | static irqreturn_t gpio_trig_irq(int irq, void *_led) | |
32 | { | |
33 | struct led_classdev *led = _led; | |
34 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
35 | ||
36 | /* just schedule_work since gpio_get_value can sleep */ | |
37 | schedule_work(&gpio_data->work); | |
38 | ||
39 | return IRQ_HANDLED; | |
40 | }; | |
41 | ||
42 | static void gpio_trig_work(struct work_struct *work) | |
43 | { | |
44 | struct gpio_trig_data *gpio_data = container_of(work, | |
45 | struct gpio_trig_data, work); | |
46 | int tmp; | |
47 | ||
74cbe202 TLSC |
48 | if (!gpio_data->gpio) |
49 | return; | |
17354bfe | 50 | |
74cbe202 TLSC |
51 | tmp = gpio_get_value(gpio_data->gpio); |
52 | if (gpio_data->inverted) | |
53 | tmp = !tmp; | |
17354bfe | 54 | |
74cbe202 TLSC |
55 | if (tmp) { |
56 | if (gpio_data->desired_brightness) | |
57 | led_set_brightness(gpio_data->led, | |
58 | gpio_data->desired_brightness); | |
59 | else | |
60 | led_set_brightness(gpio_data->led, LED_FULL); | |
61 | } else { | |
62 | led_set_brightness(gpio_data->led, LED_OFF); | |
63 | } | |
17354bfe FB |
64 | } |
65 | ||
66 | static ssize_t gpio_trig_brightness_show(struct device *dev, | |
67 | struct device_attribute *attr, char *buf) | |
68 | { | |
69 | struct led_classdev *led = dev_get_drvdata(dev); | |
70 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
71 | ||
72 | return sprintf(buf, "%u\n", gpio_data->desired_brightness); | |
73 | } | |
74 | ||
75 | static ssize_t gpio_trig_brightness_store(struct device *dev, | |
76 | struct device_attribute *attr, const char *buf, size_t n) | |
77 | { | |
78 | struct led_classdev *led = dev_get_drvdata(dev); | |
79 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
80 | unsigned desired_brightness; | |
81 | int ret; | |
82 | ||
83 | ret = sscanf(buf, "%u", &desired_brightness); | |
84 | if (ret < 1 || desired_brightness > 255) { | |
85 | dev_err(dev, "invalid value\n"); | |
86 | return -EINVAL; | |
87 | } | |
88 | ||
89 | gpio_data->desired_brightness = desired_brightness; | |
90 | ||
91 | return n; | |
92 | } | |
93 | static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show, | |
94 | gpio_trig_brightness_store); | |
95 | ||
96 | static ssize_t gpio_trig_inverted_show(struct device *dev, | |
97 | struct device_attribute *attr, char *buf) | |
98 | { | |
99 | struct led_classdev *led = dev_get_drvdata(dev); | |
100 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
101 | ||
102 | return sprintf(buf, "%s\n", gpio_data->inverted ? "yes" : "no"); | |
103 | } | |
104 | ||
105 | static ssize_t gpio_trig_inverted_store(struct device *dev, | |
106 | struct device_attribute *attr, const char *buf, size_t n) | |
107 | { | |
108 | struct led_classdev *led = dev_get_drvdata(dev); | |
109 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
110 | unsigned inverted; | |
111 | int ret; | |
112 | ||
113 | ret = sscanf(buf, "%u", &inverted); | |
114 | if (ret < 1) { | |
115 | dev_err(dev, "invalid value\n"); | |
116 | return -EINVAL; | |
117 | } | |
118 | ||
119 | gpio_data->inverted = !!inverted; | |
120 | ||
cc674c81 TLSC |
121 | /* After inverting, we need to update the LED. */ |
122 | schedule_work(&gpio_data->work); | |
123 | ||
17354bfe FB |
124 | return n; |
125 | } | |
126 | static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show, | |
127 | gpio_trig_inverted_store); | |
128 | ||
129 | static ssize_t gpio_trig_gpio_show(struct device *dev, | |
130 | struct device_attribute *attr, char *buf) | |
131 | { | |
132 | struct led_classdev *led = dev_get_drvdata(dev); | |
133 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
134 | ||
135 | return sprintf(buf, "%u\n", gpio_data->gpio); | |
136 | } | |
137 | ||
138 | static ssize_t gpio_trig_gpio_store(struct device *dev, | |
139 | struct device_attribute *attr, const char *buf, size_t n) | |
140 | { | |
141 | struct led_classdev *led = dev_get_drvdata(dev); | |
142 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
143 | unsigned gpio; | |
144 | int ret; | |
145 | ||
146 | ret = sscanf(buf, "%u", &gpio); | |
147 | if (ret < 1) { | |
148 | dev_err(dev, "couldn't read gpio number\n"); | |
149 | flush_work(&gpio_data->work); | |
150 | return -EINVAL; | |
151 | } | |
152 | ||
48cccd26 TLSC |
153 | if (gpio_data->gpio == gpio) |
154 | return n; | |
155 | ||
17354bfe | 156 | if (!gpio) { |
48cccd26 TLSC |
157 | if (gpio_data->gpio != 0) |
158 | free_irq(gpio_to_irq(gpio_data->gpio), led); | |
159 | gpio_data->gpio = 0; | |
17354bfe FB |
160 | return n; |
161 | } | |
162 | ||
17354bfe FB |
163 | ret = request_irq(gpio_to_irq(gpio), gpio_trig_irq, |
164 | IRQF_SHARED | IRQF_TRIGGER_RISING | |
165 | | IRQF_TRIGGER_FALLING, "ledtrig-gpio", led); | |
48cccd26 | 166 | if (ret) { |
17354bfe | 167 | dev_err(dev, "request_irq failed with error %d\n", ret); |
48cccd26 TLSC |
168 | } else { |
169 | if (gpio_data->gpio != 0) | |
170 | free_irq(gpio_to_irq(gpio_data->gpio), led); | |
171 | gpio_data->gpio = gpio; | |
172 | } | |
17354bfe FB |
173 | |
174 | return ret ? ret : n; | |
175 | } | |
176 | static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store); | |
177 | ||
178 | static void gpio_trig_activate(struct led_classdev *led) | |
179 | { | |
180 | struct gpio_trig_data *gpio_data; | |
181 | int ret; | |
182 | ||
183 | gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL); | |
184 | if (!gpio_data) | |
185 | return; | |
186 | ||
187 | ret = device_create_file(led->dev, &dev_attr_gpio); | |
188 | if (ret) | |
189 | goto err_gpio; | |
190 | ||
191 | ret = device_create_file(led->dev, &dev_attr_inverted); | |
192 | if (ret) | |
193 | goto err_inverted; | |
194 | ||
195 | ret = device_create_file(led->dev, &dev_attr_desired_brightness); | |
196 | if (ret) | |
197 | goto err_brightness; | |
198 | ||
199 | gpio_data->led = led; | |
200 | led->trigger_data = gpio_data; | |
201 | INIT_WORK(&gpio_data->work, gpio_trig_work); | |
202 | ||
203 | return; | |
204 | ||
205 | err_brightness: | |
206 | device_remove_file(led->dev, &dev_attr_inverted); | |
207 | ||
208 | err_inverted: | |
209 | device_remove_file(led->dev, &dev_attr_gpio); | |
210 | ||
211 | err_gpio: | |
212 | kfree(gpio_data); | |
213 | } | |
214 | ||
215 | static void gpio_trig_deactivate(struct led_classdev *led) | |
216 | { | |
217 | struct gpio_trig_data *gpio_data = led->trigger_data; | |
218 | ||
219 | if (gpio_data) { | |
220 | device_remove_file(led->dev, &dev_attr_gpio); | |
221 | device_remove_file(led->dev, &dev_attr_inverted); | |
222 | device_remove_file(led->dev, &dev_attr_desired_brightness); | |
223 | flush_work(&gpio_data->work); | |
48cccd26 TLSC |
224 | if (gpio_data->gpio != 0) |
225 | free_irq(gpio_to_irq(gpio_data->gpio), led); | |
17354bfe FB |
226 | kfree(gpio_data); |
227 | } | |
228 | } | |
229 | ||
230 | static struct led_trigger gpio_led_trigger = { | |
231 | .name = "gpio", | |
232 | .activate = gpio_trig_activate, | |
233 | .deactivate = gpio_trig_deactivate, | |
234 | }; | |
235 | ||
236 | static int __init gpio_trig_init(void) | |
237 | { | |
238 | return led_trigger_register(&gpio_led_trigger); | |
239 | } | |
240 | module_init(gpio_trig_init); | |
241 | ||
242 | static void __exit gpio_trig_exit(void) | |
243 | { | |
244 | led_trigger_unregister(&gpio_led_trigger); | |
245 | } | |
246 | module_exit(gpio_trig_exit); | |
247 | ||
248 | MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>"); | |
249 | MODULE_DESCRIPTION("GPIO LED trigger"); | |
250 | MODULE_LICENSE("GPL"); |