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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * LED Triggers Core
4 *
5 * Copyright 2005-2007 Openedhand Ltd.
6 *
7 * Author: Richard Purdie <rpurdie@openedhand.com>
8 */
9
10#include <linux/export.h>
11#include <linux/kernel.h>
12#include <linux/list.h>
13#include <linux/spinlock.h>
14#include <linux/device.h>
15#include <linux/timer.h>
16#include <linux/rwsem.h>
17#include <linux/leds.h>
18#include <linux/slab.h>
19#include <linux/mm.h>
20#include "leds.h"
21
22/*
23 * Nests outside led_cdev->trigger_lock
24 */
25static DECLARE_RWSEM(triggers_list_lock);
26LIST_HEAD(trigger_list);
27
28 /* Used by LED Class */
29
30static inline bool
31trigger_relevant(struct led_classdev *led_cdev, struct led_trigger *trig)
32{
33 return !trig->trigger_type || trig->trigger_type == led_cdev->trigger_type;
34}
35
36ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
37 struct bin_attribute *bin_attr, char *buf,
38 loff_t pos, size_t count)
39{
40 struct device *dev = kobj_to_dev(kobj);
41 struct led_classdev *led_cdev = dev_get_drvdata(dev);
42 struct led_trigger *trig;
43 int ret = count;
44
45 mutex_lock(&led_cdev->led_access);
46
47 if (led_sysfs_is_disabled(led_cdev)) {
48 ret = -EBUSY;
49 goto unlock;
50 }
51
52 if (sysfs_streq(buf, "none")) {
53 led_trigger_remove(led_cdev);
54 goto unlock;
55 }
56
57 down_read(&triggers_list_lock);
58 list_for_each_entry(trig, &trigger_list, next_trig) {
59 if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {
60 down_write(&led_cdev->trigger_lock);
61 led_trigger_set(led_cdev, trig);
62 up_write(&led_cdev->trigger_lock);
63
64 up_read(&triggers_list_lock);
65 goto unlock;
66 }
67 }
68 /* we come here only if buf matches no trigger */
69 ret = -EINVAL;
70 up_read(&triggers_list_lock);
71
72unlock:
73 mutex_unlock(&led_cdev->led_access);
74 return ret;
75}
76EXPORT_SYMBOL_GPL(led_trigger_write);
77
78__printf(3, 4)
79static int led_trigger_snprintf(char *buf, ssize_t size, const char *fmt, ...)
80{
81 va_list args;
82 int i;
83
84 va_start(args, fmt);
85 if (size <= 0)
86 i = vsnprintf(NULL, 0, fmt, args);
87 else
88 i = vscnprintf(buf, size, fmt, args);
89 va_end(args);
90
91 return i;
92}
93
94static int led_trigger_format(char *buf, size_t size,
95 struct led_classdev *led_cdev)
96{
97 struct led_trigger *trig;
98 int len = led_trigger_snprintf(buf, size, "%s",
99 led_cdev->trigger ? "none" : "[none]");
100
101 list_for_each_entry(trig, &trigger_list, next_trig) {
102 bool hit;
103
104 if (!trigger_relevant(led_cdev, trig))
105 continue;
106
107 hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name);
108
109 len += led_trigger_snprintf(buf + len, size - len,
110 " %s%s%s", hit ? "[" : "",
111 trig->name, hit ? "]" : "");
112 }
113
114 len += led_trigger_snprintf(buf + len, size - len, "\n");
115
116 return len;
117}
118
119/*
120 * It was stupid to create 10000 cpu triggers, but we are stuck with it now.
121 * Don't make that mistake again. We work around it here by creating binary
122 * attribute, which is not limited by length. This is _not_ good design, do not
123 * copy it.
124 */
125ssize_t led_trigger_read(struct file *filp, struct kobject *kobj,
126 struct bin_attribute *attr, char *buf,
127 loff_t pos, size_t count)
128{
129 struct device *dev = kobj_to_dev(kobj);
130 struct led_classdev *led_cdev = dev_get_drvdata(dev);
131 void *data;
132 int len;
133
134 down_read(&triggers_list_lock);
135 down_read(&led_cdev->trigger_lock);
136
137 len = led_trigger_format(NULL, 0, led_cdev);
138 data = kvmalloc(len + 1, GFP_KERNEL);
139 if (!data) {
140 up_read(&led_cdev->trigger_lock);
141 up_read(&triggers_list_lock);
142 return -ENOMEM;
143 }
144 len = led_trigger_format(data, len + 1, led_cdev);
145
146 up_read(&led_cdev->trigger_lock);
147 up_read(&triggers_list_lock);
148
149 len = memory_read_from_buffer(buf, count, &pos, data, len);
150
151 kvfree(data);
152
153 return len;
154}
155EXPORT_SYMBOL_GPL(led_trigger_read);
156
157/* Caller must ensure led_cdev->trigger_lock held */
158int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
159{
160 char *event = NULL;
161 char *envp[2];
162 const char *name;
163 int ret;
164
165 if (!led_cdev->trigger && !trig)
166 return 0;
167
168 name = trig ? trig->name : "none";
169 event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
170
171 /* Remove any existing trigger */
172 if (led_cdev->trigger) {
173 spin_lock(&led_cdev->trigger->leddev_list_lock);
174 list_del_rcu(&led_cdev->trig_list);
175 spin_unlock(&led_cdev->trigger->leddev_list_lock);
176
177 /* ensure it's no longer visible on the led_cdevs list */
178 synchronize_rcu();
179
180 cancel_work_sync(&led_cdev->set_brightness_work);
181 led_stop_software_blink(led_cdev);
182 if (led_cdev->trigger->deactivate)
183 led_cdev->trigger->deactivate(led_cdev);
184 device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
185 led_cdev->trigger = NULL;
186 led_cdev->trigger_data = NULL;
187 led_cdev->activated = false;
188 led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
189 led_set_brightness(led_cdev, LED_OFF);
190 }
191 if (trig) {
192 spin_lock(&trig->leddev_list_lock);
193 list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs);
194 spin_unlock(&trig->leddev_list_lock);
195 led_cdev->trigger = trig;
196
197 if (trig->activate)
198 ret = trig->activate(led_cdev);
199 else
200 ret = 0;
201
202 if (ret)
203 goto err_activate;
204
205 ret = device_add_groups(led_cdev->dev, trig->groups);
206 if (ret) {
207 dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
208 goto err_add_groups;
209 }
210 }
211
212 if (event) {
213 envp[0] = event;
214 envp[1] = NULL;
215 if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
216 dev_err(led_cdev->dev,
217 "%s: Error sending uevent\n", __func__);
218 kfree(event);
219 }
220
221 return 0;
222
223err_add_groups:
224
225 if (trig->deactivate)
226 trig->deactivate(led_cdev);
227err_activate:
228
229 spin_lock(&led_cdev->trigger->leddev_list_lock);
230 list_del_rcu(&led_cdev->trig_list);
231 spin_unlock(&led_cdev->trigger->leddev_list_lock);
232 synchronize_rcu();
233 led_cdev->trigger = NULL;
234 led_cdev->trigger_data = NULL;
235 led_set_brightness(led_cdev, LED_OFF);
236 kfree(event);
237
238 return ret;
239}
240EXPORT_SYMBOL_GPL(led_trigger_set);
241
242void led_trigger_remove(struct led_classdev *led_cdev)
243{
244 down_write(&led_cdev->trigger_lock);
245 led_trigger_set(led_cdev, NULL);
246 up_write(&led_cdev->trigger_lock);
247}
248EXPORT_SYMBOL_GPL(led_trigger_remove);
249
250void led_trigger_set_default(struct led_classdev *led_cdev)
251{
252 struct led_trigger *trig;
253
254 if (!led_cdev->default_trigger)
255 return;
256
257 down_read(&triggers_list_lock);
258 down_write(&led_cdev->trigger_lock);
259 list_for_each_entry(trig, &trigger_list, next_trig) {
260 if (!strcmp(led_cdev->default_trigger, trig->name) &&
261 trigger_relevant(led_cdev, trig)) {
262 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
263 led_trigger_set(led_cdev, trig);
264 break;
265 }
266 }
267 up_write(&led_cdev->trigger_lock);
268 up_read(&triggers_list_lock);
269}
270EXPORT_SYMBOL_GPL(led_trigger_set_default);
271
272/* LED Trigger Interface */
273
274int led_trigger_register(struct led_trigger *trig)
275{
276 struct led_classdev *led_cdev;
277 struct led_trigger *_trig;
278
279 spin_lock_init(&trig->leddev_list_lock);
280 INIT_LIST_HEAD(&trig->led_cdevs);
281
282 down_write(&triggers_list_lock);
283 /* Make sure the trigger's name isn't already in use */
284 list_for_each_entry(_trig, &trigger_list, next_trig) {
285 if (!strcmp(_trig->name, trig->name) &&
286 (trig->trigger_type == _trig->trigger_type ||
287 !trig->trigger_type || !_trig->trigger_type)) {
288 up_write(&triggers_list_lock);
289 return -EEXIST;
290 }
291 }
292 /* Add to the list of led triggers */
293 list_add_tail(&trig->next_trig, &trigger_list);
294 up_write(&triggers_list_lock);
295
296 /* Register with any LEDs that have this as a default trigger */
297 down_read(&leds_list_lock);
298 list_for_each_entry(led_cdev, &leds_list, node) {
299 down_write(&led_cdev->trigger_lock);
300 if (!led_cdev->trigger && led_cdev->default_trigger &&
301 !strcmp(led_cdev->default_trigger, trig->name) &&
302 trigger_relevant(led_cdev, trig)) {
303 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
304 led_trigger_set(led_cdev, trig);
305 }
306 up_write(&led_cdev->trigger_lock);
307 }
308 up_read(&leds_list_lock);
309
310 return 0;
311}
312EXPORT_SYMBOL_GPL(led_trigger_register);
313
314void led_trigger_unregister(struct led_trigger *trig)
315{
316 struct led_classdev *led_cdev;
317
318 if (list_empty_careful(&trig->next_trig))
319 return;
320
321 /* Remove from the list of led triggers */
322 down_write(&triggers_list_lock);
323 list_del_init(&trig->next_trig);
324 up_write(&triggers_list_lock);
325
326 /* Remove anyone actively using this trigger */
327 down_read(&leds_list_lock);
328 list_for_each_entry(led_cdev, &leds_list, node) {
329 down_write(&led_cdev->trigger_lock);
330 if (led_cdev->trigger == trig)
331 led_trigger_set(led_cdev, NULL);
332 up_write(&led_cdev->trigger_lock);
333 }
334 up_read(&leds_list_lock);
335}
336EXPORT_SYMBOL_GPL(led_trigger_unregister);
337
338static void devm_led_trigger_release(struct device *dev, void *res)
339{
340 led_trigger_unregister(*(struct led_trigger **)res);
341}
342
343int devm_led_trigger_register(struct device *dev,
344 struct led_trigger *trig)
345{
346 struct led_trigger **dr;
347 int rc;
348
349 dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
350 GFP_KERNEL);
351 if (!dr)
352 return -ENOMEM;
353
354 *dr = trig;
355
356 rc = led_trigger_register(trig);
357 if (rc)
358 devres_free(dr);
359 else
360 devres_add(dev, dr);
361
362 return rc;
363}
364EXPORT_SYMBOL_GPL(devm_led_trigger_register);
365
366/* Simple LED Trigger Interface */
367
368void led_trigger_event(struct led_trigger *trig,
369 enum led_brightness brightness)
370{
371 struct led_classdev *led_cdev;
372
373 if (!trig)
374 return;
375
376 rcu_read_lock();
377 list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)
378 led_set_brightness(led_cdev, brightness);
379 rcu_read_unlock();
380}
381EXPORT_SYMBOL_GPL(led_trigger_event);
382
383static void led_trigger_blink_setup(struct led_trigger *trig,
384 unsigned long delay_on,
385 unsigned long delay_off,
386 int oneshot,
387 int invert)
388{
389 struct led_classdev *led_cdev;
390
391 if (!trig)
392 return;
393
394 rcu_read_lock();
395 list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
396 if (oneshot)
397 led_blink_set_oneshot(led_cdev, &delay_on, &delay_off,
398 invert);
399 else
400 led_blink_set_nosleep(led_cdev, delay_on, delay_off);
401 }
402 rcu_read_unlock();
403}
404
405void led_trigger_blink(struct led_trigger *trig,
406 unsigned long delay_on,
407 unsigned long delay_off)
408{
409 led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
410}
411EXPORT_SYMBOL_GPL(led_trigger_blink);
412
413void led_trigger_blink_oneshot(struct led_trigger *trig,
414 unsigned long delay_on,
415 unsigned long delay_off,
416 int invert)
417{
418 led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
419}
420EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
421
422void led_trigger_register_simple(const char *name, struct led_trigger **tp)
423{
424 struct led_trigger *trig;
425 int err;
426
427 trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
428
429 if (trig) {
430 trig->name = name;
431 err = led_trigger_register(trig);
432 if (err < 0) {
433 kfree(trig);
434 trig = NULL;
435 pr_warn("LED trigger %s failed to register (%d)\n",
436 name, err);
437 }
438 } else {
439 pr_warn("LED trigger %s failed to register (no memory)\n",
440 name);
441 }
442 *tp = trig;
443}
444EXPORT_SYMBOL_GPL(led_trigger_register_simple);
445
446void led_trigger_unregister_simple(struct led_trigger *trig)
447{
448 if (trig)
449 led_trigger_unregister(trig);
450 kfree(trig);
451}
452EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
1/*
2 * LED Triggers Core
3 *
4 * Copyright 2005-2007 Openedhand Ltd.
5 *
6 * Author: Richard Purdie <rpurdie@openedhand.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 */
13
14#include <linux/module.h>
15#include <linux/kernel.h>
16#include <linux/init.h>
17#include <linux/list.h>
18#include <linux/spinlock.h>
19#include <linux/device.h>
20#include <linux/sysdev.h>
21#include <linux/timer.h>
22#include <linux/rwsem.h>
23#include <linux/leds.h>
24#include <linux/slab.h>
25#include "leds.h"
26
27/*
28 * Nests outside led_cdev->trigger_lock
29 */
30static DECLARE_RWSEM(triggers_list_lock);
31static LIST_HEAD(trigger_list);
32
33 /* Used by LED Class */
34
35ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
36 const char *buf, size_t count)
37{
38 struct led_classdev *led_cdev = dev_get_drvdata(dev);
39 char trigger_name[TRIG_NAME_MAX];
40 struct led_trigger *trig;
41 size_t len;
42
43 trigger_name[sizeof(trigger_name) - 1] = '\0';
44 strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
45 len = strlen(trigger_name);
46
47 if (len && trigger_name[len - 1] == '\n')
48 trigger_name[len - 1] = '\0';
49
50 if (!strcmp(trigger_name, "none")) {
51 led_trigger_remove(led_cdev);
52 return count;
53 }
54
55 down_read(&triggers_list_lock);
56 list_for_each_entry(trig, &trigger_list, next_trig) {
57 if (!strcmp(trigger_name, trig->name)) {
58 down_write(&led_cdev->trigger_lock);
59 led_trigger_set(led_cdev, trig);
60 up_write(&led_cdev->trigger_lock);
61
62 up_read(&triggers_list_lock);
63 return count;
64 }
65 }
66 up_read(&triggers_list_lock);
67
68 return -EINVAL;
69}
70EXPORT_SYMBOL_GPL(led_trigger_store);
71
72ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
73 char *buf)
74{
75 struct led_classdev *led_cdev = dev_get_drvdata(dev);
76 struct led_trigger *trig;
77 int len = 0;
78
79 down_read(&triggers_list_lock);
80 down_read(&led_cdev->trigger_lock);
81
82 if (!led_cdev->trigger)
83 len += sprintf(buf+len, "[none] ");
84 else
85 len += sprintf(buf+len, "none ");
86
87 list_for_each_entry(trig, &trigger_list, next_trig) {
88 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
89 trig->name))
90 len += sprintf(buf+len, "[%s] ", trig->name);
91 else
92 len += sprintf(buf+len, "%s ", trig->name);
93 }
94 up_read(&led_cdev->trigger_lock);
95 up_read(&triggers_list_lock);
96
97 len += sprintf(len+buf, "\n");
98 return len;
99}
100EXPORT_SYMBOL_GPL(led_trigger_show);
101
102/* Caller must ensure led_cdev->trigger_lock held */
103void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger)
104{
105 unsigned long flags;
106
107 /* Remove any existing trigger */
108 if (led_cdev->trigger) {
109 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
110 list_del(&led_cdev->trig_list);
111 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
112 flags);
113 if (led_cdev->trigger->deactivate)
114 led_cdev->trigger->deactivate(led_cdev);
115 led_cdev->trigger = NULL;
116 led_brightness_set(led_cdev, LED_OFF);
117 }
118 if (trigger) {
119 write_lock_irqsave(&trigger->leddev_list_lock, flags);
120 list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs);
121 write_unlock_irqrestore(&trigger->leddev_list_lock, flags);
122 led_cdev->trigger = trigger;
123 if (trigger->activate)
124 trigger->activate(led_cdev);
125 }
126}
127EXPORT_SYMBOL_GPL(led_trigger_set);
128
129void led_trigger_remove(struct led_classdev *led_cdev)
130{
131 down_write(&led_cdev->trigger_lock);
132 led_trigger_set(led_cdev, NULL);
133 up_write(&led_cdev->trigger_lock);
134}
135EXPORT_SYMBOL_GPL(led_trigger_remove);
136
137void led_trigger_set_default(struct led_classdev *led_cdev)
138{
139 struct led_trigger *trig;
140
141 if (!led_cdev->default_trigger)
142 return;
143
144 down_read(&triggers_list_lock);
145 down_write(&led_cdev->trigger_lock);
146 list_for_each_entry(trig, &trigger_list, next_trig) {
147 if (!strcmp(led_cdev->default_trigger, trig->name))
148 led_trigger_set(led_cdev, trig);
149 }
150 up_write(&led_cdev->trigger_lock);
151 up_read(&triggers_list_lock);
152}
153EXPORT_SYMBOL_GPL(led_trigger_set_default);
154
155/* LED Trigger Interface */
156
157int led_trigger_register(struct led_trigger *trigger)
158{
159 struct led_classdev *led_cdev;
160 struct led_trigger *trig;
161
162 rwlock_init(&trigger->leddev_list_lock);
163 INIT_LIST_HEAD(&trigger->led_cdevs);
164
165 down_write(&triggers_list_lock);
166 /* Make sure the trigger's name isn't already in use */
167 list_for_each_entry(trig, &trigger_list, next_trig) {
168 if (!strcmp(trig->name, trigger->name)) {
169 up_write(&triggers_list_lock);
170 return -EEXIST;
171 }
172 }
173 /* Add to the list of led triggers */
174 list_add_tail(&trigger->next_trig, &trigger_list);
175 up_write(&triggers_list_lock);
176
177 /* Register with any LEDs that have this as a default trigger */
178 down_read(&leds_list_lock);
179 list_for_each_entry(led_cdev, &leds_list, node) {
180 down_write(&led_cdev->trigger_lock);
181 if (!led_cdev->trigger && led_cdev->default_trigger &&
182 !strcmp(led_cdev->default_trigger, trigger->name))
183 led_trigger_set(led_cdev, trigger);
184 up_write(&led_cdev->trigger_lock);
185 }
186 up_read(&leds_list_lock);
187
188 return 0;
189}
190EXPORT_SYMBOL_GPL(led_trigger_register);
191
192void led_trigger_unregister(struct led_trigger *trigger)
193{
194 struct led_classdev *led_cdev;
195
196 /* Remove from the list of led triggers */
197 down_write(&triggers_list_lock);
198 list_del(&trigger->next_trig);
199 up_write(&triggers_list_lock);
200
201 /* Remove anyone actively using this trigger */
202 down_read(&leds_list_lock);
203 list_for_each_entry(led_cdev, &leds_list, node) {
204 down_write(&led_cdev->trigger_lock);
205 if (led_cdev->trigger == trigger)
206 led_trigger_set(led_cdev, NULL);
207 up_write(&led_cdev->trigger_lock);
208 }
209 up_read(&leds_list_lock);
210}
211EXPORT_SYMBOL_GPL(led_trigger_unregister);
212
213/* Simple LED Tigger Interface */
214
215void led_trigger_event(struct led_trigger *trigger,
216 enum led_brightness brightness)
217{
218 struct list_head *entry;
219
220 if (!trigger)
221 return;
222
223 read_lock(&trigger->leddev_list_lock);
224 list_for_each(entry, &trigger->led_cdevs) {
225 struct led_classdev *led_cdev;
226
227 led_cdev = list_entry(entry, struct led_classdev, trig_list);
228 led_set_brightness(led_cdev, brightness);
229 }
230 read_unlock(&trigger->leddev_list_lock);
231}
232EXPORT_SYMBOL_GPL(led_trigger_event);
233
234void led_trigger_blink(struct led_trigger *trigger,
235 unsigned long *delay_on,
236 unsigned long *delay_off)
237{
238 struct list_head *entry;
239
240 if (!trigger)
241 return;
242
243 read_lock(&trigger->leddev_list_lock);
244 list_for_each(entry, &trigger->led_cdevs) {
245 struct led_classdev *led_cdev;
246
247 led_cdev = list_entry(entry, struct led_classdev, trig_list);
248 led_blink_set(led_cdev, delay_on, delay_off);
249 }
250 read_unlock(&trigger->leddev_list_lock);
251}
252EXPORT_SYMBOL_GPL(led_trigger_blink);
253
254void led_trigger_register_simple(const char *name, struct led_trigger **tp)
255{
256 struct led_trigger *trigger;
257 int err;
258
259 trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
260
261 if (trigger) {
262 trigger->name = name;
263 err = led_trigger_register(trigger);
264 if (err < 0)
265 printk(KERN_WARNING "LED trigger %s failed to register"
266 " (%d)\n", name, err);
267 } else
268 printk(KERN_WARNING "LED trigger %s failed to register"
269 " (no memory)\n", name);
270
271 *tp = trigger;
272}
273EXPORT_SYMBOL_GPL(led_trigger_register_simple);
274
275void led_trigger_unregister_simple(struct led_trigger *trigger)
276{
277 if (trigger)
278 led_trigger_unregister(trigger);
279 kfree(trigger);
280}
281EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
282
283MODULE_AUTHOR("Richard Purdie");
284MODULE_LICENSE("GPL");
285MODULE_DESCRIPTION("LED Triggers Core");