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/export.h>
15 #include <linux/kernel.h>
16 #include <linux/list.h>
17 #include <linux/spinlock.h>
18 #include <linux/device.h>
19 #include <linux/timer.h>
20 #include <linux/rwsem.h>
21 #include <linux/leds.h>
22 #include <linux/slab.h>
23 #include "leds.h"
24
25 /*
26 * Nests outside led_cdev->trigger_lock
27 */
28 static DECLARE_RWSEM(triggers_list_lock);
29 LIST_HEAD(trigger_list);
30
31 /* Used by LED Class */
32
led_trigger_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)33 ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
34 const char *buf, size_t count)
35 {
36 struct led_classdev *led_cdev = dev_get_drvdata(dev);
37 struct led_trigger *trig;
38 int ret = count;
39
40 mutex_lock(&led_cdev->led_access);
41
42 if (led_sysfs_is_disabled(led_cdev)) {
43 ret = -EBUSY;
44 goto unlock;
45 }
46
47 if (sysfs_streq(buf, "none")) {
48 led_trigger_remove(led_cdev);
49 goto unlock;
50 }
51
52 down_read(&triggers_list_lock);
53 list_for_each_entry(trig, &trigger_list, next_trig) {
54 if (sysfs_streq(buf, trig->name)) {
55 down_write(&led_cdev->trigger_lock);
56 led_trigger_set(led_cdev, trig);
57 up_write(&led_cdev->trigger_lock);
58
59 up_read(&triggers_list_lock);
60 goto unlock;
61 }
62 }
63 /* we come here only if buf matches no trigger */
64 ret = -EINVAL;
65 up_read(&triggers_list_lock);
66
67 unlock:
68 mutex_unlock(&led_cdev->led_access);
69 return ret;
70 }
71 EXPORT_SYMBOL_GPL(led_trigger_store);
72
led_trigger_show(struct device * dev,struct device_attribute * attr,char * buf)73 ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
74 char *buf)
75 {
76 struct led_classdev *led_cdev = dev_get_drvdata(dev);
77 struct led_trigger *trig;
78 int len = 0;
79
80 down_read(&triggers_list_lock);
81 down_read(&led_cdev->trigger_lock);
82
83 if (!led_cdev->trigger)
84 len += scnprintf(buf+len, PAGE_SIZE - len, "[none] ");
85 else
86 len += scnprintf(buf+len, PAGE_SIZE - len, "none ");
87
88 list_for_each_entry(trig, &trigger_list, next_trig) {
89 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
90 trig->name))
91 len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ",
92 trig->name);
93 else
94 len += scnprintf(buf+len, PAGE_SIZE - len, "%s ",
95 trig->name);
96 }
97 up_read(&led_cdev->trigger_lock);
98 up_read(&triggers_list_lock);
99
100 len += scnprintf(len+buf, PAGE_SIZE - len, "\n");
101 return len;
102 }
103 EXPORT_SYMBOL_GPL(led_trigger_show);
104
105 /* Caller must ensure led_cdev->trigger_lock held */
led_trigger_set(struct led_classdev * led_cdev,struct led_trigger * trig)106 void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
107 {
108 unsigned long flags;
109 char *event = NULL;
110 char *envp[2];
111 const char *name;
112
113 if (!led_cdev->trigger && !trig)
114 return;
115
116 name = trig ? trig->name : "none";
117 event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
118
119 /* Remove any existing trigger */
120 if (led_cdev->trigger) {
121 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
122 list_del(&led_cdev->trig_list);
123 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
124 flags);
125 cancel_work_sync(&led_cdev->set_brightness_work);
126 led_stop_software_blink(led_cdev);
127 if (led_cdev->trigger->deactivate)
128 led_cdev->trigger->deactivate(led_cdev);
129 led_cdev->trigger = NULL;
130 led_set_brightness(led_cdev, LED_OFF);
131 }
132 if (trig) {
133 write_lock_irqsave(&trig->leddev_list_lock, flags);
134 list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
135 write_unlock_irqrestore(&trig->leddev_list_lock, flags);
136 led_cdev->trigger = trig;
137 if (trig->activate)
138 trig->activate(led_cdev);
139 }
140
141 if (event) {
142 envp[0] = event;
143 envp[1] = NULL;
144 if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
145 dev_err(led_cdev->dev,
146 "%s: Error sending uevent\n", __func__);
147 kfree(event);
148 }
149 }
150 EXPORT_SYMBOL_GPL(led_trigger_set);
151
led_trigger_remove(struct led_classdev * led_cdev)152 void led_trigger_remove(struct led_classdev *led_cdev)
153 {
154 down_write(&led_cdev->trigger_lock);
155 led_trigger_set(led_cdev, NULL);
156 up_write(&led_cdev->trigger_lock);
157 }
158 EXPORT_SYMBOL_GPL(led_trigger_remove);
159
led_trigger_set_default(struct led_classdev * led_cdev)160 void led_trigger_set_default(struct led_classdev *led_cdev)
161 {
162 struct led_trigger *trig;
163
164 if (!led_cdev->default_trigger)
165 return;
166
167 down_read(&triggers_list_lock);
168 down_write(&led_cdev->trigger_lock);
169 list_for_each_entry(trig, &trigger_list, next_trig) {
170 if (!strcmp(led_cdev->default_trigger, trig->name))
171 led_trigger_set(led_cdev, trig);
172 }
173 up_write(&led_cdev->trigger_lock);
174 up_read(&triggers_list_lock);
175 }
176 EXPORT_SYMBOL_GPL(led_trigger_set_default);
177
led_trigger_rename_static(const char * name,struct led_trigger * trig)178 void led_trigger_rename_static(const char *name, struct led_trigger *trig)
179 {
180 /* new name must be on a temporary string to prevent races */
181 BUG_ON(name == trig->name);
182
183 down_write(&triggers_list_lock);
184 /* this assumes that trig->name was originaly allocated to
185 * non constant storage */
186 strcpy((char *)trig->name, name);
187 up_write(&triggers_list_lock);
188 }
189 EXPORT_SYMBOL_GPL(led_trigger_rename_static);
190
191 /* LED Trigger Interface */
192
led_trigger_register(struct led_trigger * trig)193 int led_trigger_register(struct led_trigger *trig)
194 {
195 struct led_classdev *led_cdev;
196 struct led_trigger *_trig;
197
198 rwlock_init(&trig->leddev_list_lock);
199 INIT_LIST_HEAD(&trig->led_cdevs);
200
201 down_write(&triggers_list_lock);
202 /* Make sure the trigger's name isn't already in use */
203 list_for_each_entry(_trig, &trigger_list, next_trig) {
204 if (!strcmp(_trig->name, trig->name)) {
205 up_write(&triggers_list_lock);
206 return -EEXIST;
207 }
208 }
209 /* Add to the list of led triggers */
210 list_add_tail(&trig->next_trig, &trigger_list);
211 up_write(&triggers_list_lock);
212
213 /* Register with any LEDs that have this as a default trigger */
214 down_read(&leds_list_lock);
215 list_for_each_entry(led_cdev, &leds_list, node) {
216 down_write(&led_cdev->trigger_lock);
217 if (!led_cdev->trigger && led_cdev->default_trigger &&
218 !strcmp(led_cdev->default_trigger, trig->name))
219 led_trigger_set(led_cdev, trig);
220 up_write(&led_cdev->trigger_lock);
221 }
222 up_read(&leds_list_lock);
223
224 return 0;
225 }
226 EXPORT_SYMBOL_GPL(led_trigger_register);
227
led_trigger_unregister(struct led_trigger * trig)228 void led_trigger_unregister(struct led_trigger *trig)
229 {
230 struct led_classdev *led_cdev;
231
232 if (list_empty_careful(&trig->next_trig))
233 return;
234
235 /* Remove from the list of led triggers */
236 down_write(&triggers_list_lock);
237 list_del_init(&trig->next_trig);
238 up_write(&triggers_list_lock);
239
240 /* Remove anyone actively using this trigger */
241 down_read(&leds_list_lock);
242 list_for_each_entry(led_cdev, &leds_list, node) {
243 down_write(&led_cdev->trigger_lock);
244 if (led_cdev->trigger == trig)
245 led_trigger_set(led_cdev, NULL);
246 up_write(&led_cdev->trigger_lock);
247 }
248 up_read(&leds_list_lock);
249 }
250 EXPORT_SYMBOL_GPL(led_trigger_unregister);
251
devm_led_trigger_release(struct device * dev,void * res)252 static void devm_led_trigger_release(struct device *dev, void *res)
253 {
254 led_trigger_unregister(*(struct led_trigger **)res);
255 }
256
devm_led_trigger_register(struct device * dev,struct led_trigger * trig)257 int devm_led_trigger_register(struct device *dev,
258 struct led_trigger *trig)
259 {
260 struct led_trigger **dr;
261 int rc;
262
263 dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
264 GFP_KERNEL);
265 if (!dr)
266 return -ENOMEM;
267
268 *dr = trig;
269
270 rc = led_trigger_register(trig);
271 if (rc)
272 devres_free(dr);
273 else
274 devres_add(dev, dr);
275
276 return rc;
277 }
278 EXPORT_SYMBOL_GPL(devm_led_trigger_register);
279
280 /* Simple LED Tigger Interface */
281
led_trigger_event(struct led_trigger * trig,enum led_brightness brightness)282 void led_trigger_event(struct led_trigger *trig,
283 enum led_brightness brightness)
284 {
285 struct led_classdev *led_cdev;
286
287 if (!trig)
288 return;
289
290 read_lock(&trig->leddev_list_lock);
291 list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
292 led_set_brightness(led_cdev, brightness);
293 read_unlock(&trig->leddev_list_lock);
294 }
295 EXPORT_SYMBOL_GPL(led_trigger_event);
296
led_trigger_blink_setup(struct led_trigger * trig,unsigned long * delay_on,unsigned long * delay_off,int oneshot,int invert)297 static void led_trigger_blink_setup(struct led_trigger *trig,
298 unsigned long *delay_on,
299 unsigned long *delay_off,
300 int oneshot,
301 int invert)
302 {
303 struct led_classdev *led_cdev;
304
305 if (!trig)
306 return;
307
308 read_lock(&trig->leddev_list_lock);
309 list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
310 if (oneshot)
311 led_blink_set_oneshot(led_cdev, delay_on, delay_off,
312 invert);
313 else
314 led_blink_set(led_cdev, delay_on, delay_off);
315 }
316 read_unlock(&trig->leddev_list_lock);
317 }
318
led_trigger_blink(struct led_trigger * trig,unsigned long * delay_on,unsigned long * delay_off)319 void led_trigger_blink(struct led_trigger *trig,
320 unsigned long *delay_on,
321 unsigned long *delay_off)
322 {
323 led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
324 }
325 EXPORT_SYMBOL_GPL(led_trigger_blink);
326
led_trigger_blink_oneshot(struct led_trigger * trig,unsigned long * delay_on,unsigned long * delay_off,int invert)327 void led_trigger_blink_oneshot(struct led_trigger *trig,
328 unsigned long *delay_on,
329 unsigned long *delay_off,
330 int invert)
331 {
332 led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
333 }
334 EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
335
led_trigger_register_simple(const char * name,struct led_trigger ** tp)336 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
337 {
338 struct led_trigger *trig;
339 int err;
340
341 trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
342
343 if (trig) {
344 trig->name = name;
345 err = led_trigger_register(trig);
346 if (err < 0) {
347 kfree(trig);
348 trig = NULL;
349 pr_warn("LED trigger %s failed to register (%d)\n",
350 name, err);
351 }
352 } else {
353 pr_warn("LED trigger %s failed to register (no memory)\n",
354 name);
355 }
356 *tp = trig;
357 }
358 EXPORT_SYMBOL_GPL(led_trigger_register_simple);
359
led_trigger_unregister_simple(struct led_trigger * trig)360 void led_trigger_unregister_simple(struct led_trigger *trig)
361 {
362 if (trig)
363 led_trigger_unregister(trig);
364 kfree(trig);
365 }
366 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
367