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[mirror_ubuntu-artful-kernel.git] / drivers / leds / led-triggers.c
CommitLineData
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1/*
2 * LED Triggers Core
3 *
f8a7c6fe 4 * Copyright 2005-2007 Openedhand Ltd.
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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
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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>
c3bc9956 20#include <linux/timer.h>
dc47206e 21#include <linux/rwsem.h>
c3bc9956 22#include <linux/leds.h>
5a0e3ad6 23#include <linux/slab.h>
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24#include "leds.h"
25
26/*
27 * Nests outside led_cdev->trigger_lock
28 */
dc47206e 29static DECLARE_RWSEM(triggers_list_lock);
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30static LIST_HEAD(trigger_list);
31
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32 /* Used by LED Class */
33
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34ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
35 const char *buf, size_t count)
c3bc9956 36{
f8a7c6fe 37 struct led_classdev *led_cdev = dev_get_drvdata(dev);
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38 char trigger_name[TRIG_NAME_MAX];
39 struct led_trigger *trig;
40 size_t len;
41
42 trigger_name[sizeof(trigger_name) - 1] = '\0';
43 strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
44 len = strlen(trigger_name);
45
46 if (len && trigger_name[len - 1] == '\n')
47 trigger_name[len - 1] = '\0';
48
49 if (!strcmp(trigger_name, "none")) {
0013b23d 50 led_trigger_remove(led_cdev);
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51 return count;
52 }
53
dc47206e 54 down_read(&triggers_list_lock);
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55 list_for_each_entry(trig, &trigger_list, next_trig) {
56 if (!strcmp(trigger_name, trig->name)) {
dc47206e 57 down_write(&led_cdev->trigger_lock);
c3bc9956 58 led_trigger_set(led_cdev, trig);
dc47206e 59 up_write(&led_cdev->trigger_lock);
c3bc9956 60
dc47206e 61 up_read(&triggers_list_lock);
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62 return count;
63 }
64 }
dc47206e 65 up_read(&triggers_list_lock);
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66
67 return -EINVAL;
68}
4d404fd5 69EXPORT_SYMBOL_GPL(led_trigger_store);
c3bc9956 70
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71ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
72 char *buf)
c3bc9956 73{
f8a7c6fe 74 struct led_classdev *led_cdev = dev_get_drvdata(dev);
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75 struct led_trigger *trig;
76 int len = 0;
77
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78 down_read(&triggers_list_lock);
79 down_read(&led_cdev->trigger_lock);
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80
81 if (!led_cdev->trigger)
82 len += sprintf(buf+len, "[none] ");
83 else
84 len += sprintf(buf+len, "none ");
85
86 list_for_each_entry(trig, &trigger_list, next_trig) {
87 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
88 trig->name))
89 len += sprintf(buf+len, "[%s] ", trig->name);
90 else
91 len += sprintf(buf+len, "%s ", trig->name);
92 }
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93 up_read(&led_cdev->trigger_lock);
94 up_read(&triggers_list_lock);
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95
96 len += sprintf(len+buf, "\n");
97 return len;
98}
4d404fd5 99EXPORT_SYMBOL_GPL(led_trigger_show);
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100
101/* Caller must ensure led_cdev->trigger_lock held */
eb202621 102void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
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103{
104 unsigned long flags;
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105 char *event = NULL;
106 char *envp[2];
107 const char *name;
108
109 name = trig ? trig->name : "none";
110 event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
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111
112 /* Remove any existing trigger */
113 if (led_cdev->trigger) {
114 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
115 list_del(&led_cdev->trig_list);
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116 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
117 flags);
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118 cancel_work_sync(&led_cdev->set_brightness_work);
119 led_stop_software_blink(led_cdev);
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120 if (led_cdev->trigger->deactivate)
121 led_cdev->trigger->deactivate(led_cdev);
fe3025b5 122 led_cdev->trigger = NULL;
19cd67e2 123 led_set_brightness(led_cdev, LED_OFF);
c3bc9956 124 }
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125 if (trig) {
126 write_lock_irqsave(&trig->leddev_list_lock, flags);
127 list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
128 write_unlock_irqrestore(&trig->leddev_list_lock, flags);
129 led_cdev->trigger = trig;
130 if (trig->activate)
131 trig->activate(led_cdev);
c3bc9956 132 }
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133
134 if (event) {
135 envp[0] = event;
136 envp[1] = NULL;
137 kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp);
138 kfree(event);
139 }
c3bc9956 140}
4d404fd5 141EXPORT_SYMBOL_GPL(led_trigger_set);
c3bc9956 142
0013b23d
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143void led_trigger_remove(struct led_classdev *led_cdev)
144{
145 down_write(&led_cdev->trigger_lock);
146 led_trigger_set(led_cdev, NULL);
147 up_write(&led_cdev->trigger_lock);
148}
4d404fd5 149EXPORT_SYMBOL_GPL(led_trigger_remove);
0013b23d 150
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151void led_trigger_set_default(struct led_classdev *led_cdev)
152{
153 struct led_trigger *trig;
154
155 if (!led_cdev->default_trigger)
156 return;
157
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158 down_read(&triggers_list_lock);
159 down_write(&led_cdev->trigger_lock);
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160 list_for_each_entry(trig, &trigger_list, next_trig) {
161 if (!strcmp(led_cdev->default_trigger, trig->name))
162 led_trigger_set(led_cdev, trig);
163 }
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164 up_write(&led_cdev->trigger_lock);
165 up_read(&triggers_list_lock);
c3bc9956 166}
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167EXPORT_SYMBOL_GPL(led_trigger_set_default);
168
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169void led_trigger_rename_static(const char *name, struct led_trigger *trig)
170{
171 /* new name must be on a temporary string to prevent races */
172 BUG_ON(name == trig->name);
173
174 down_write(&triggers_list_lock);
175 /* this assumes that trig->name was originaly allocated to
176 * non constant storage */
177 strcpy((char *)trig->name, name);
178 up_write(&triggers_list_lock);
179}
180EXPORT_SYMBOL_GPL(led_trigger_rename_static);
181
4d404fd5 182/* LED Trigger Interface */
c3bc9956 183
eb202621 184int led_trigger_register(struct led_trigger *trig)
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185{
186 struct led_classdev *led_cdev;
eb202621 187 struct led_trigger *_trig;
c3bc9956 188
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189 rwlock_init(&trig->leddev_list_lock);
190 INIT_LIST_HEAD(&trig->led_cdevs);
c3bc9956 191
dc47206e 192 down_write(&triggers_list_lock);
700c6ea2 193 /* Make sure the trigger's name isn't already in use */
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194 list_for_each_entry(_trig, &trigger_list, next_trig) {
195 if (!strcmp(_trig->name, trig->name)) {
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196 up_write(&triggers_list_lock);
197 return -EEXIST;
198 }
199 }
200 /* Add to the list of led triggers */
eb202621 201 list_add_tail(&trig->next_trig, &trigger_list);
dc47206e 202 up_write(&triggers_list_lock);
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203
204 /* Register with any LEDs that have this as a default trigger */
72f8da32 205 down_read(&leds_list_lock);
c3bc9956 206 list_for_each_entry(led_cdev, &leds_list, node) {
dc47206e 207 down_write(&led_cdev->trigger_lock);
c3bc9956 208 if (!led_cdev->trigger && led_cdev->default_trigger &&
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209 !strcmp(led_cdev->default_trigger, trig->name))
210 led_trigger_set(led_cdev, trig);
dc47206e 211 up_write(&led_cdev->trigger_lock);
c3bc9956 212 }
72f8da32 213 up_read(&leds_list_lock);
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214
215 return 0;
216}
4d404fd5 217EXPORT_SYMBOL_GPL(led_trigger_register);
c3bc9956 218
eb202621 219void led_trigger_unregister(struct led_trigger *trig)
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220{
221 struct led_classdev *led_cdev;
222
223 /* Remove from the list of led triggers */
dc47206e 224 down_write(&triggers_list_lock);
eb202621 225 list_del(&trig->next_trig);
dc47206e 226 up_write(&triggers_list_lock);
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227
228 /* Remove anyone actively using this trigger */
72f8da32 229 down_read(&leds_list_lock);
c3bc9956 230 list_for_each_entry(led_cdev, &leds_list, node) {
dc47206e 231 down_write(&led_cdev->trigger_lock);
eb202621 232 if (led_cdev->trigger == trig)
c3bc9956 233 led_trigger_set(led_cdev, NULL);
dc47206e 234 up_write(&led_cdev->trigger_lock);
c3bc9956 235 }
72f8da32 236 up_read(&leds_list_lock);
c3bc9956 237}
4d404fd5 238EXPORT_SYMBOL_GPL(led_trigger_unregister);
c3bc9956 239
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240/* Simple LED Tigger Interface */
241
eb202621 242void led_trigger_event(struct led_trigger *trig,
4d404fd5 243 enum led_brightness brightness)
c3bc9956 244{
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245 struct list_head *entry;
246
eb202621 247 if (!trig)
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248 return;
249
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250 read_lock(&trig->leddev_list_lock);
251 list_for_each(entry, &trig->led_cdevs) {
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252 struct led_classdev *led_cdev;
253
254 led_cdev = list_entry(entry, struct led_classdev, trig_list);
d23a22a7 255 led_set_brightness(led_cdev, brightness);
4d404fd5 256 }
eb202621 257 read_unlock(&trig->leddev_list_lock);
c3bc9956 258}
4d404fd5 259EXPORT_SYMBOL_GPL(led_trigger_event);
c3bc9956 260
20c0e6b8 261static void led_trigger_blink_setup(struct led_trigger *trig,
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262 unsigned long *delay_on,
263 unsigned long *delay_off,
264 int oneshot,
265 int invert)
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266{
267 struct list_head *entry;
268
eb202621 269 if (!trig)
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270 return;
271
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272 read_lock(&trig->leddev_list_lock);
273 list_for_each(entry, &trig->led_cdevs) {
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274 struct led_classdev *led_cdev;
275
276 led_cdev = list_entry(entry, struct led_classdev, trig_list);
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277 if (oneshot)
278 led_blink_set_oneshot(led_cdev, delay_on, delay_off,
279 invert);
280 else
281 led_blink_set(led_cdev, delay_on, delay_off);
0b9536c9 282 }
eb202621 283 read_unlock(&trig->leddev_list_lock);
0b9536c9 284}
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285
286void led_trigger_blink(struct led_trigger *trig,
287 unsigned long *delay_on,
288 unsigned long *delay_off)
289{
290 led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
291}
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292EXPORT_SYMBOL_GPL(led_trigger_blink);
293
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294void led_trigger_blink_oneshot(struct led_trigger *trig,
295 unsigned long *delay_on,
296 unsigned long *delay_off,
297 int invert)
298{
299 led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
300}
301EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
302
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303void led_trigger_register_simple(const char *name, struct led_trigger **tp)
304{
eb202621 305 struct led_trigger *trig;
4d404fd5 306 int err;
c3bc9956 307
eb202621 308 trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
c3bc9956 309
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310 if (trig) {
311 trig->name = name;
312 err = led_trigger_register(trig);
cba4c2ac 313 if (err < 0) {
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314 kfree(trig);
315 trig = NULL;
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316 pr_warn("LED trigger %s failed to register (%d)\n",
317 name, err);
cba4c2ac 318 }
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319 } else {
320 pr_warn("LED trigger %s failed to register (no memory)\n",
321 name);
322 }
eb202621 323 *tp = trig;
4d404fd5 324}
c3bc9956 325EXPORT_SYMBOL_GPL(led_trigger_register_simple);
4d404fd5 326
eb202621 327void led_trigger_unregister_simple(struct led_trigger *trig)
4d404fd5 328{
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329 if (trig)
330 led_trigger_unregister(trig);
331 kfree(trig);
4d404fd5 332}
c3bc9956 333EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
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334
335MODULE_AUTHOR("Richard Purdie");
336MODULE_LICENSE("GPL");
337MODULE_DESCRIPTION("LED Triggers Core");