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 | */ |
25 | static DECLARE_RWSEM(triggers_list_lock); |
26 | LIST_HEAD(trigger_list); |
27 | |
28 | /* Used by LED Class */ |
29 | |
30 | static inline bool |
31 | trigger_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 | |
36 | ssize_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(s1: buf, s2: "none" )) { |
53 | led_trigger_remove(led_cdev); |
54 | goto unlock; |
55 | } |
56 | |
57 | down_read(sem: &triggers_list_lock); |
58 | list_for_each_entry(trig, &trigger_list, next_trig) { |
59 | if (sysfs_streq(s1: buf, s2: trig->name) && trigger_relevant(led_cdev, trig)) { |
60 | down_write(sem: &led_cdev->trigger_lock); |
61 | led_trigger_set(led_cdev, trigger: trig); |
62 | up_write(sem: &led_cdev->trigger_lock); |
63 | |
64 | up_read(sem: &triggers_list_lock); |
65 | goto unlock; |
66 | } |
67 | } |
68 | /* we come here only if buf matches no trigger */ |
69 | ret = -EINVAL; |
70 | up_read(sem: &triggers_list_lock); |
71 | |
72 | unlock: |
73 | mutex_unlock(lock: &led_cdev->led_access); |
74 | return ret; |
75 | } |
76 | EXPORT_SYMBOL_GPL(led_trigger_write); |
77 | |
78 | __printf(3, 4) |
79 | static 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, size: 0, fmt, args); |
87 | else |
88 | i = vscnprintf(buf, size, fmt, args); |
89 | va_end(args); |
90 | |
91 | return i; |
92 | } |
93 | |
94 | static 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, fmt: "%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: buf + len, size: size - len, |
110 | fmt: " %s%s%s" , hit ? "[" : "" , |
111 | trig->name, hit ? "]" : "" ); |
112 | } |
113 | |
114 | len += led_trigger_snprintf(buf: buf + len, size: size - len, fmt: "\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 | */ |
125 | ssize_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(sem: &triggers_list_lock); |
135 | down_read(sem: &led_cdev->trigger_lock); |
136 | |
137 | len = led_trigger_format(NULL, size: 0, led_cdev); |
138 | data = kvmalloc(size: len + 1, GFP_KERNEL); |
139 | if (!data) { |
140 | up_read(sem: &led_cdev->trigger_lock); |
141 | up_read(sem: &triggers_list_lock); |
142 | return -ENOMEM; |
143 | } |
144 | len = led_trigger_format(buf: data, size: len + 1, led_cdev); |
145 | |
146 | up_read(sem: &led_cdev->trigger_lock); |
147 | up_read(sem: &triggers_list_lock); |
148 | |
149 | len = memory_read_from_buffer(to: buf, count, ppos: &pos, from: data, available: len); |
150 | |
151 | kvfree(addr: data); |
152 | |
153 | return len; |
154 | } |
155 | EXPORT_SYMBOL_GPL(led_trigger_read); |
156 | |
157 | /* Caller must ensure led_cdev->trigger_lock held */ |
158 | int 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, fmt: "TRIGGER=%s" , name); |
170 | |
171 | /* Remove any existing trigger */ |
172 | if (led_cdev->trigger) { |
173 | spin_lock(lock: &led_cdev->trigger->leddev_list_lock); |
174 | list_del_rcu(entry: &led_cdev->trig_list); |
175 | spin_unlock(lock: &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(work: &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(dev: led_cdev->dev, groups: 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, brightness: LED_OFF); |
190 | } |
191 | if (trig) { |
192 | spin_lock(lock: &trig->leddev_list_lock); |
193 | list_add_tail_rcu(new: &led_cdev->trig_list, head: &trig->led_cdevs); |
194 | spin_unlock(lock: &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(dev: led_cdev->dev, groups: 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(kobj: &led_cdev->dev->kobj, action: KOBJ_CHANGE, envp)) |
216 | dev_err(led_cdev->dev, |
217 | "%s: Error sending uevent\n" , __func__); |
218 | kfree(objp: event); |
219 | } |
220 | |
221 | return 0; |
222 | |
223 | err_add_groups: |
224 | |
225 | if (trig->deactivate) |
226 | trig->deactivate(led_cdev); |
227 | err_activate: |
228 | |
229 | spin_lock(lock: &led_cdev->trigger->leddev_list_lock); |
230 | list_del_rcu(entry: &led_cdev->trig_list); |
231 | spin_unlock(lock: &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, brightness: LED_OFF); |
236 | kfree(objp: event); |
237 | |
238 | return ret; |
239 | } |
240 | EXPORT_SYMBOL_GPL(led_trigger_set); |
241 | |
242 | void led_trigger_remove(struct led_classdev *led_cdev) |
243 | { |
244 | down_write(sem: &led_cdev->trigger_lock); |
245 | led_trigger_set(led_cdev, NULL); |
246 | up_write(sem: &led_cdev->trigger_lock); |
247 | } |
248 | EXPORT_SYMBOL_GPL(led_trigger_remove); |
249 | |
250 | void 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(sem: &triggers_list_lock); |
258 | down_write(sem: &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(sem: &led_cdev->trigger_lock); |
268 | up_read(sem: &triggers_list_lock); |
269 | } |
270 | EXPORT_SYMBOL_GPL(led_trigger_set_default); |
271 | |
272 | void led_trigger_rename_static(const char *name, struct led_trigger *trig) |
273 | { |
274 | /* new name must be on a temporary string to prevent races */ |
275 | BUG_ON(name == trig->name); |
276 | |
277 | down_write(sem: &triggers_list_lock); |
278 | /* this assumes that trig->name was originaly allocated to |
279 | * non constant storage */ |
280 | strcpy(p: (char *)trig->name, q: name); |
281 | up_write(sem: &triggers_list_lock); |
282 | } |
283 | EXPORT_SYMBOL_GPL(led_trigger_rename_static); |
284 | |
285 | /* LED Trigger Interface */ |
286 | |
287 | int led_trigger_register(struct led_trigger *trig) |
288 | { |
289 | struct led_classdev *led_cdev; |
290 | struct led_trigger *_trig; |
291 | |
292 | spin_lock_init(&trig->leddev_list_lock); |
293 | INIT_LIST_HEAD(list: &trig->led_cdevs); |
294 | |
295 | down_write(sem: &triggers_list_lock); |
296 | /* Make sure the trigger's name isn't already in use */ |
297 | list_for_each_entry(_trig, &trigger_list, next_trig) { |
298 | if (!strcmp(_trig->name, trig->name) && |
299 | (trig->trigger_type == _trig->trigger_type || |
300 | !trig->trigger_type || !_trig->trigger_type)) { |
301 | up_write(sem: &triggers_list_lock); |
302 | return -EEXIST; |
303 | } |
304 | } |
305 | /* Add to the list of led triggers */ |
306 | list_add_tail(new: &trig->next_trig, head: &trigger_list); |
307 | up_write(sem: &triggers_list_lock); |
308 | |
309 | /* Register with any LEDs that have this as a default trigger */ |
310 | down_read(sem: &leds_list_lock); |
311 | list_for_each_entry(led_cdev, &leds_list, node) { |
312 | down_write(sem: &led_cdev->trigger_lock); |
313 | if (!led_cdev->trigger && led_cdev->default_trigger && |
314 | !strcmp(led_cdev->default_trigger, trig->name) && |
315 | trigger_relevant(led_cdev, trig)) { |
316 | led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER; |
317 | led_trigger_set(led_cdev, trig); |
318 | } |
319 | up_write(sem: &led_cdev->trigger_lock); |
320 | } |
321 | up_read(sem: &leds_list_lock); |
322 | |
323 | return 0; |
324 | } |
325 | EXPORT_SYMBOL_GPL(led_trigger_register); |
326 | |
327 | void led_trigger_unregister(struct led_trigger *trig) |
328 | { |
329 | struct led_classdev *led_cdev; |
330 | |
331 | if (list_empty_careful(head: &trig->next_trig)) |
332 | return; |
333 | |
334 | /* Remove from the list of led triggers */ |
335 | down_write(sem: &triggers_list_lock); |
336 | list_del_init(entry: &trig->next_trig); |
337 | up_write(sem: &triggers_list_lock); |
338 | |
339 | /* Remove anyone actively using this trigger */ |
340 | down_read(sem: &leds_list_lock); |
341 | list_for_each_entry(led_cdev, &leds_list, node) { |
342 | down_write(sem: &led_cdev->trigger_lock); |
343 | if (led_cdev->trigger == trig) |
344 | led_trigger_set(led_cdev, NULL); |
345 | up_write(sem: &led_cdev->trigger_lock); |
346 | } |
347 | up_read(sem: &leds_list_lock); |
348 | } |
349 | EXPORT_SYMBOL_GPL(led_trigger_unregister); |
350 | |
351 | static void devm_led_trigger_release(struct device *dev, void *res) |
352 | { |
353 | led_trigger_unregister(*(struct led_trigger **)res); |
354 | } |
355 | |
356 | int devm_led_trigger_register(struct device *dev, |
357 | struct led_trigger *trig) |
358 | { |
359 | struct led_trigger **dr; |
360 | int rc; |
361 | |
362 | dr = devres_alloc(devm_led_trigger_release, sizeof(*dr), |
363 | GFP_KERNEL); |
364 | if (!dr) |
365 | return -ENOMEM; |
366 | |
367 | *dr = trig; |
368 | |
369 | rc = led_trigger_register(trig); |
370 | if (rc) |
371 | devres_free(res: dr); |
372 | else |
373 | devres_add(dev, res: dr); |
374 | |
375 | return rc; |
376 | } |
377 | EXPORT_SYMBOL_GPL(devm_led_trigger_register); |
378 | |
379 | /* Simple LED Trigger Interface */ |
380 | |
381 | void led_trigger_event(struct led_trigger *trig, |
382 | enum led_brightness brightness) |
383 | { |
384 | struct led_classdev *led_cdev; |
385 | |
386 | if (!trig) |
387 | return; |
388 | |
389 | rcu_read_lock(); |
390 | list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) |
391 | led_set_brightness(led_cdev, brightness); |
392 | rcu_read_unlock(); |
393 | } |
394 | EXPORT_SYMBOL_GPL(led_trigger_event); |
395 | |
396 | static void led_trigger_blink_setup(struct led_trigger *trig, |
397 | unsigned long delay_on, |
398 | unsigned long delay_off, |
399 | int oneshot, |
400 | int invert) |
401 | { |
402 | struct led_classdev *led_cdev; |
403 | |
404 | if (!trig) |
405 | return; |
406 | |
407 | rcu_read_lock(); |
408 | list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) { |
409 | if (oneshot) |
410 | led_blink_set_oneshot(led_cdev, delay_on: &delay_on, delay_off: &delay_off, |
411 | invert); |
412 | else |
413 | led_blink_set_nosleep(led_cdev, delay_on, delay_off); |
414 | } |
415 | rcu_read_unlock(); |
416 | } |
417 | |
418 | void led_trigger_blink(struct led_trigger *trig, |
419 | unsigned long delay_on, |
420 | unsigned long delay_off) |
421 | { |
422 | led_trigger_blink_setup(trig, delay_on, delay_off, oneshot: 0, invert: 0); |
423 | } |
424 | EXPORT_SYMBOL_GPL(led_trigger_blink); |
425 | |
426 | void led_trigger_blink_oneshot(struct led_trigger *trig, |
427 | unsigned long delay_on, |
428 | unsigned long delay_off, |
429 | int invert) |
430 | { |
431 | led_trigger_blink_setup(trig, delay_on, delay_off, oneshot: 1, invert); |
432 | } |
433 | EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot); |
434 | |
435 | void led_trigger_register_simple(const char *name, struct led_trigger **tp) |
436 | { |
437 | struct led_trigger *trig; |
438 | int err; |
439 | |
440 | trig = kzalloc(size: sizeof(struct led_trigger), GFP_KERNEL); |
441 | |
442 | if (trig) { |
443 | trig->name = name; |
444 | err = led_trigger_register(trig); |
445 | if (err < 0) { |
446 | kfree(objp: trig); |
447 | trig = NULL; |
448 | pr_warn("LED trigger %s failed to register (%d)\n" , |
449 | name, err); |
450 | } |
451 | } else { |
452 | pr_warn("LED trigger %s failed to register (no memory)\n" , |
453 | name); |
454 | } |
455 | *tp = trig; |
456 | } |
457 | EXPORT_SYMBOL_GPL(led_trigger_register_simple); |
458 | |
459 | void led_trigger_unregister_simple(struct led_trigger *trig) |
460 | { |
461 | if (trig) |
462 | led_trigger_unregister(trig); |
463 | kfree(objp: trig); |
464 | } |
465 | EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); |
466 | |