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 "leds.h"
20
21 /*
22 * Nests outside led_cdev->trigger_lock
23 */
24 static DECLARE_RWSEM(triggers_list_lock);
25 LIST_HEAD(trigger_list);
26
27 /* Used by LED Class */
28
led_trigger_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)29 ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
30 const char *buf, size_t count)
31 {
32 struct led_classdev *led_cdev = dev_get_drvdata(dev);
33 struct led_trigger *trig;
34 int ret = count;
35
36 mutex_lock(&led_cdev->led_access);
37
38 if (led_sysfs_is_disabled(led_cdev)) {
39 ret = -EBUSY;
40 goto unlock;
41 }
42
43 if (sysfs_streq(buf, "none")) {
44 led_trigger_remove(led_cdev);
45 goto unlock;
46 }
47
48 down_read(&triggers_list_lock);
49 list_for_each_entry(trig, &trigger_list, next_trig) {
50 if (sysfs_streq(buf, trig->name)) {
51 down_write(&led_cdev->trigger_lock);
52 led_trigger_set(led_cdev, trig);
53 up_write(&led_cdev->trigger_lock);
54
55 up_read(&triggers_list_lock);
56 goto unlock;
57 }
58 }
59 /* we come here only if buf matches no trigger */
60 ret = -EINVAL;
61 up_read(&triggers_list_lock);
62
63 unlock:
64 mutex_unlock(&led_cdev->led_access);
65 return ret;
66 }
67 EXPORT_SYMBOL_GPL(led_trigger_store);
68
led_trigger_show(struct device * dev,struct device_attribute * attr,char * buf)69 ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
70 char *buf)
71 {
72 struct led_classdev *led_cdev = dev_get_drvdata(dev);
73 struct led_trigger *trig;
74 int len = 0;
75
76 down_read(&triggers_list_lock);
77 down_read(&led_cdev->trigger_lock);
78
79 if (!led_cdev->trigger)
80 len += scnprintf(buf+len, PAGE_SIZE - len, "[none] ");
81 else
82 len += scnprintf(buf+len, PAGE_SIZE - len, "none ");
83
84 list_for_each_entry(trig, &trigger_list, next_trig) {
85 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
86 trig->name))
87 len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ",
88 trig->name);
89 else
90 len += scnprintf(buf+len, PAGE_SIZE - len, "%s ",
91 trig->name);
92 }
93 up_read(&led_cdev->trigger_lock);
94 up_read(&triggers_list_lock);
95
96 len += scnprintf(len+buf, PAGE_SIZE - len, "\n");
97 return len;
98 }
99 EXPORT_SYMBOL_GPL(led_trigger_show);
100
101 /* Caller must ensure led_cdev->trigger_lock held */
led_trigger_set(struct led_classdev * led_cdev,struct led_trigger * trig)102 int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
103 {
104 unsigned long flags;
105 char *event = NULL;
106 char *envp[2];
107 const char *name;
108 int ret;
109
110 if (!led_cdev->trigger && !trig)
111 return 0;
112
113 name = trig ? trig->name : "none";
114 event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
115
116 /* Remove any existing trigger */
117 if (led_cdev->trigger) {
118 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
119 list_del(&led_cdev->trig_list);
120 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
121 flags);
122 cancel_work_sync(&led_cdev->set_brightness_work);
123 led_stop_software_blink(led_cdev);
124 if (led_cdev->trigger->deactivate)
125 led_cdev->trigger->deactivate(led_cdev);
126 device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
127 led_cdev->trigger = NULL;
128 led_cdev->trigger_data = NULL;
129 led_cdev->activated = false;
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
138 if (trig->activate)
139 ret = trig->activate(led_cdev);
140 else
141 ret = 0;
142
143 if (ret)
144 goto err_activate;
145
146 ret = device_add_groups(led_cdev->dev, trig->groups);
147 if (ret) {
148 dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
149 goto err_add_groups;
150 }
151 }
152
153 if (event) {
154 envp[0] = event;
155 envp[1] = NULL;
156 if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
157 dev_err(led_cdev->dev,
158 "%s: Error sending uevent\n", __func__);
159 kfree(event);
160 }
161
162 return 0;
163
164 err_add_groups:
165
166 if (trig->deactivate)
167 trig->deactivate(led_cdev);
168 err_activate:
169
170 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
171 list_del(&led_cdev->trig_list);
172 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
173 led_cdev->trigger = NULL;
174 led_cdev->trigger_data = NULL;
175 led_set_brightness(led_cdev, LED_OFF);
176 kfree(event);
177
178 return ret;
179 }
180 EXPORT_SYMBOL_GPL(led_trigger_set);
181
led_trigger_remove(struct led_classdev * led_cdev)182 void led_trigger_remove(struct led_classdev *led_cdev)
183 {
184 down_write(&led_cdev->trigger_lock);
185 led_trigger_set(led_cdev, NULL);
186 up_write(&led_cdev->trigger_lock);
187 }
188 EXPORT_SYMBOL_GPL(led_trigger_remove);
189
led_trigger_set_default(struct led_classdev * led_cdev)190 void led_trigger_set_default(struct led_classdev *led_cdev)
191 {
192 struct led_trigger *trig;
193
194 if (!led_cdev->default_trigger)
195 return;
196
197 down_read(&triggers_list_lock);
198 down_write(&led_cdev->trigger_lock);
199 list_for_each_entry(trig, &trigger_list, next_trig) {
200 if (!strcmp(led_cdev->default_trigger, trig->name)) {
201 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
202 led_trigger_set(led_cdev, trig);
203 break;
204 }
205 }
206 up_write(&led_cdev->trigger_lock);
207 up_read(&triggers_list_lock);
208 }
209 EXPORT_SYMBOL_GPL(led_trigger_set_default);
210
led_trigger_rename_static(const char * name,struct led_trigger * trig)211 void led_trigger_rename_static(const char *name, struct led_trigger *trig)
212 {
213 /* new name must be on a temporary string to prevent races */
214 BUG_ON(name == trig->name);
215
216 down_write(&triggers_list_lock);
217 /* this assumes that trig->name was originaly allocated to
218 * non constant storage */
219 strcpy((char *)trig->name, name);
220 up_write(&triggers_list_lock);
221 }
222 EXPORT_SYMBOL_GPL(led_trigger_rename_static);
223
224 /* LED Trigger Interface */
225
led_trigger_register(struct led_trigger * trig)226 int led_trigger_register(struct led_trigger *trig)
227 {
228 struct led_classdev *led_cdev;
229 struct led_trigger *_trig;
230
231 rwlock_init(&trig->leddev_list_lock);
232 INIT_LIST_HEAD(&trig->led_cdevs);
233
234 down_write(&triggers_list_lock);
235 /* Make sure the trigger's name isn't already in use */
236 list_for_each_entry(_trig, &trigger_list, next_trig) {
237 if (!strcmp(_trig->name, trig->name)) {
238 up_write(&triggers_list_lock);
239 return -EEXIST;
240 }
241 }
242 /* Add to the list of led triggers */
243 list_add_tail(&trig->next_trig, &trigger_list);
244 up_write(&triggers_list_lock);
245
246 /* Register with any LEDs that have this as a default trigger */
247 down_read(&leds_list_lock);
248 list_for_each_entry(led_cdev, &leds_list, node) {
249 down_write(&led_cdev->trigger_lock);
250 if (!led_cdev->trigger && led_cdev->default_trigger &&
251 !strcmp(led_cdev->default_trigger, trig->name)) {
252 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
253 led_trigger_set(led_cdev, trig);
254 }
255 up_write(&led_cdev->trigger_lock);
256 }
257 up_read(&leds_list_lock);
258
259 return 0;
260 }
261 EXPORT_SYMBOL_GPL(led_trigger_register);
262
led_trigger_unregister(struct led_trigger * trig)263 void led_trigger_unregister(struct led_trigger *trig)
264 {
265 struct led_classdev *led_cdev;
266
267 if (list_empty_careful(&trig->next_trig))
268 return;
269
270 /* Remove from the list of led triggers */
271 down_write(&triggers_list_lock);
272 list_del_init(&trig->next_trig);
273 up_write(&triggers_list_lock);
274
275 /* Remove anyone actively using this trigger */
276 down_read(&leds_list_lock);
277 list_for_each_entry(led_cdev, &leds_list, node) {
278 down_write(&led_cdev->trigger_lock);
279 if (led_cdev->trigger == trig)
280 led_trigger_set(led_cdev, NULL);
281 up_write(&led_cdev->trigger_lock);
282 }
283 up_read(&leds_list_lock);
284 }
285 EXPORT_SYMBOL_GPL(led_trigger_unregister);
286
devm_led_trigger_release(struct device * dev,void * res)287 static void devm_led_trigger_release(struct device *dev, void *res)
288 {
289 led_trigger_unregister(*(struct led_trigger **)res);
290 }
291
devm_led_trigger_register(struct device * dev,struct led_trigger * trig)292 int devm_led_trigger_register(struct device *dev,
293 struct led_trigger *trig)
294 {
295 struct led_trigger **dr;
296 int rc;
297
298 dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
299 GFP_KERNEL);
300 if (!dr)
301 return -ENOMEM;
302
303 *dr = trig;
304
305 rc = led_trigger_register(trig);
306 if (rc)
307 devres_free(dr);
308 else
309 devres_add(dev, dr);
310
311 return rc;
312 }
313 EXPORT_SYMBOL_GPL(devm_led_trigger_register);
314
315 /* Simple LED Tigger Interface */
316
led_trigger_event(struct led_trigger * trig,enum led_brightness brightness)317 void led_trigger_event(struct led_trigger *trig,
318 enum led_brightness brightness)
319 {
320 struct led_classdev *led_cdev;
321
322 if (!trig)
323 return;
324
325 read_lock(&trig->leddev_list_lock);
326 list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
327 led_set_brightness(led_cdev, brightness);
328 read_unlock(&trig->leddev_list_lock);
329 }
330 EXPORT_SYMBOL_GPL(led_trigger_event);
331
led_trigger_blink_setup(struct led_trigger * trig,unsigned long * delay_on,unsigned long * delay_off,int oneshot,int invert)332 static void led_trigger_blink_setup(struct led_trigger *trig,
333 unsigned long *delay_on,
334 unsigned long *delay_off,
335 int oneshot,
336 int invert)
337 {
338 struct led_classdev *led_cdev;
339
340 if (!trig)
341 return;
342
343 read_lock(&trig->leddev_list_lock);
344 list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
345 if (oneshot)
346 led_blink_set_oneshot(led_cdev, delay_on, delay_off,
347 invert);
348 else
349 led_blink_set(led_cdev, delay_on, delay_off);
350 }
351 read_unlock(&trig->leddev_list_lock);
352 }
353
led_trigger_blink(struct led_trigger * trig,unsigned long * delay_on,unsigned long * delay_off)354 void led_trigger_blink(struct led_trigger *trig,
355 unsigned long *delay_on,
356 unsigned long *delay_off)
357 {
358 led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
359 }
360 EXPORT_SYMBOL_GPL(led_trigger_blink);
361
led_trigger_blink_oneshot(struct led_trigger * trig,unsigned long * delay_on,unsigned long * delay_off,int invert)362 void led_trigger_blink_oneshot(struct led_trigger *trig,
363 unsigned long *delay_on,
364 unsigned long *delay_off,
365 int invert)
366 {
367 led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
368 }
369 EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
370
led_trigger_register_simple(const char * name,struct led_trigger ** tp)371 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
372 {
373 struct led_trigger *trig;
374 int err;
375
376 trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
377
378 if (trig) {
379 trig->name = name;
380 err = led_trigger_register(trig);
381 if (err < 0) {
382 kfree(trig);
383 trig = NULL;
384 pr_warn("LED trigger %s failed to register (%d)\n",
385 name, err);
386 }
387 } else {
388 pr_warn("LED trigger %s failed to register (no memory)\n",
389 name);
390 }
391 *tp = trig;
392 }
393 EXPORT_SYMBOL_GPL(led_trigger_register_simple);
394
led_trigger_unregister_simple(struct led_trigger * trig)395 void led_trigger_unregister_simple(struct led_trigger *trig)
396 {
397 if (trig)
398 led_trigger_unregister(trig);
399 kfree(trig);
400 }
401 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
402