1 // SPDX-License-Identifier: GPL-2.0-only
5 * Copyright 2005-2007 Openedhand Ltd.
7 * Author: Richard Purdie <rpurdie@openedhand.com>
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>
23 * Nests outside led_cdev->trigger_lock
25 static DECLARE_RWSEM(triggers_list_lock);
26 LIST_HEAD(trigger_list);
28 /* Used by LED Class */
31 trigger_relevant(struct led_classdev *led_cdev, struct led_trigger *trig)
33 return !trig->trigger_type || trig->trigger_type == led_cdev->trigger_type;
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)
40 struct device *dev = kobj_to_dev(kobj);
41 struct led_classdev *led_cdev = dev_get_drvdata(dev);
42 struct led_trigger *trig;
45 mutex_lock(&led_cdev->led_access);
47 if (led_sysfs_is_disabled(led_cdev)) {
52 if (sysfs_streq(buf, "none")) {
53 led_trigger_remove(led_cdev);
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);
64 up_read(&triggers_list_lock);
68 /* we come here only if buf matches no trigger */
70 up_read(&triggers_list_lock);
73 mutex_unlock(&led_cdev->led_access);
76 EXPORT_SYMBOL_GPL(led_trigger_write);
79 static int led_trigger_snprintf(char *buf, ssize_t size, const char *fmt, ...)
86 i = vsnprintf(NULL, 0, fmt, args);
88 i = vscnprintf(buf, size, fmt, args);
94 static int led_trigger_format(char *buf, size_t size,
95 struct led_classdev *led_cdev)
97 struct led_trigger *trig;
98 int len = led_trigger_snprintf(buf, size, "%s",
99 led_cdev->trigger ? "none" : "[none]");
101 list_for_each_entry(trig, &trigger_list, next_trig) {
104 if (!trigger_relevant(led_cdev, trig))
107 hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name);
109 len += led_trigger_snprintf(buf + len, size - len,
110 " %s%s%s", hit ? "[" : "",
111 trig->name, hit ? "]" : "");
114 len += led_trigger_snprintf(buf + len, size - len, "\n");
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
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)
129 struct device *dev = kobj_to_dev(kobj);
130 struct led_classdev *led_cdev = dev_get_drvdata(dev);
134 down_read(&triggers_list_lock);
135 down_read(&led_cdev->trigger_lock);
137 len = led_trigger_format(NULL, 0, led_cdev);
138 data = kvmalloc(len + 1, GFP_KERNEL);
140 up_read(&led_cdev->trigger_lock);
141 up_read(&triggers_list_lock);
144 len = led_trigger_format(data, len + 1, led_cdev);
146 up_read(&led_cdev->trigger_lock);
147 up_read(&triggers_list_lock);
149 len = memory_read_from_buffer(buf, count, &pos, data, len);
155 EXPORT_SYMBOL_GPL(led_trigger_read);
157 /* Caller must ensure led_cdev->trigger_lock held */
158 int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
166 if (!led_cdev->trigger && !trig)
169 name = trig ? trig->name : "none";
170 event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
172 /* Remove any existing trigger */
173 if (led_cdev->trigger) {
174 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
175 list_del(&led_cdev->trig_list);
176 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
178 cancel_work_sync(&led_cdev->set_brightness_work);
179 led_stop_software_blink(led_cdev);
180 if (led_cdev->trigger->deactivate)
181 led_cdev->trigger->deactivate(led_cdev);
182 device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
183 led_cdev->trigger = NULL;
184 led_cdev->trigger_data = NULL;
185 led_cdev->activated = false;
186 led_set_brightness(led_cdev, LED_OFF);
189 write_lock_irqsave(&trig->leddev_list_lock, flags);
190 list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
191 write_unlock_irqrestore(&trig->leddev_list_lock, flags);
192 led_cdev->trigger = trig;
195 ret = trig->activate(led_cdev);
202 ret = device_add_groups(led_cdev->dev, trig->groups);
204 dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
212 if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
213 dev_err(led_cdev->dev,
214 "%s: Error sending uevent\n", __func__);
222 if (trig->deactivate)
223 trig->deactivate(led_cdev);
226 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
227 list_del(&led_cdev->trig_list);
228 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
229 led_cdev->trigger = NULL;
230 led_cdev->trigger_data = NULL;
231 led_set_brightness(led_cdev, LED_OFF);
236 EXPORT_SYMBOL_GPL(led_trigger_set);
238 void led_trigger_remove(struct led_classdev *led_cdev)
240 down_write(&led_cdev->trigger_lock);
241 led_trigger_set(led_cdev, NULL);
242 up_write(&led_cdev->trigger_lock);
244 EXPORT_SYMBOL_GPL(led_trigger_remove);
246 void led_trigger_set_default(struct led_classdev *led_cdev)
248 struct led_trigger *trig;
250 if (!led_cdev->default_trigger)
253 down_read(&triggers_list_lock);
254 down_write(&led_cdev->trigger_lock);
255 list_for_each_entry(trig, &trigger_list, next_trig) {
256 if (!strcmp(led_cdev->default_trigger, trig->name) &&
257 trigger_relevant(led_cdev, trig)) {
258 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
259 led_trigger_set(led_cdev, trig);
263 up_write(&led_cdev->trigger_lock);
264 up_read(&triggers_list_lock);
266 EXPORT_SYMBOL_GPL(led_trigger_set_default);
268 void led_trigger_rename_static(const char *name, struct led_trigger *trig)
270 /* new name must be on a temporary string to prevent races */
271 BUG_ON(name == trig->name);
273 down_write(&triggers_list_lock);
274 /* this assumes that trig->name was originaly allocated to
275 * non constant storage */
276 strcpy((char *)trig->name, name);
277 up_write(&triggers_list_lock);
279 EXPORT_SYMBOL_GPL(led_trigger_rename_static);
281 /* LED Trigger Interface */
283 int led_trigger_register(struct led_trigger *trig)
285 struct led_classdev *led_cdev;
286 struct led_trigger *_trig;
288 rwlock_init(&trig->leddev_list_lock);
289 INIT_LIST_HEAD(&trig->led_cdevs);
291 down_write(&triggers_list_lock);
292 /* Make sure the trigger's name isn't already in use */
293 list_for_each_entry(_trig, &trigger_list, next_trig) {
294 if (!strcmp(_trig->name, trig->name) &&
295 (trig->trigger_type == _trig->trigger_type ||
296 !trig->trigger_type || !_trig->trigger_type)) {
297 up_write(&triggers_list_lock);
301 /* Add to the list of led triggers */
302 list_add_tail(&trig->next_trig, &trigger_list);
303 up_write(&triggers_list_lock);
305 /* Register with any LEDs that have this as a default trigger */
306 down_read(&leds_list_lock);
307 list_for_each_entry(led_cdev, &leds_list, node) {
308 down_write(&led_cdev->trigger_lock);
309 if (!led_cdev->trigger && led_cdev->default_trigger &&
310 !strcmp(led_cdev->default_trigger, trig->name) &&
311 trigger_relevant(led_cdev, trig)) {
312 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
313 led_trigger_set(led_cdev, trig);
315 up_write(&led_cdev->trigger_lock);
317 up_read(&leds_list_lock);
321 EXPORT_SYMBOL_GPL(led_trigger_register);
323 void led_trigger_unregister(struct led_trigger *trig)
325 struct led_classdev *led_cdev;
327 if (list_empty_careful(&trig->next_trig))
330 /* Remove from the list of led triggers */
331 down_write(&triggers_list_lock);
332 list_del_init(&trig->next_trig);
333 up_write(&triggers_list_lock);
335 /* Remove anyone actively using this trigger */
336 down_read(&leds_list_lock);
337 list_for_each_entry(led_cdev, &leds_list, node) {
338 down_write(&led_cdev->trigger_lock);
339 if (led_cdev->trigger == trig)
340 led_trigger_set(led_cdev, NULL);
341 up_write(&led_cdev->trigger_lock);
343 up_read(&leds_list_lock);
345 EXPORT_SYMBOL_GPL(led_trigger_unregister);
347 static void devm_led_trigger_release(struct device *dev, void *res)
349 led_trigger_unregister(*(struct led_trigger **)res);
352 int devm_led_trigger_register(struct device *dev,
353 struct led_trigger *trig)
355 struct led_trigger **dr;
358 dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
365 rc = led_trigger_register(trig);
373 EXPORT_SYMBOL_GPL(devm_led_trigger_register);
375 /* Simple LED Trigger Interface */
377 void led_trigger_event(struct led_trigger *trig,
378 enum led_brightness brightness)
380 struct led_classdev *led_cdev;
386 read_lock_irqsave(&trig->leddev_list_lock, flags);
387 list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
388 led_set_brightness(led_cdev, brightness);
389 read_unlock_irqrestore(&trig->leddev_list_lock, flags);
391 EXPORT_SYMBOL_GPL(led_trigger_event);
393 static void led_trigger_blink_setup(struct led_trigger *trig,
394 unsigned long *delay_on,
395 unsigned long *delay_off,
399 struct led_classdev *led_cdev;
405 read_lock_irqsave(&trig->leddev_list_lock, flags);
406 list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
408 led_blink_set_oneshot(led_cdev, delay_on, delay_off,
411 led_blink_set(led_cdev, delay_on, delay_off);
413 read_unlock_irqrestore(&trig->leddev_list_lock, flags);
416 void led_trigger_blink(struct led_trigger *trig,
417 unsigned long *delay_on,
418 unsigned long *delay_off)
420 led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
422 EXPORT_SYMBOL_GPL(led_trigger_blink);
424 void led_trigger_blink_oneshot(struct led_trigger *trig,
425 unsigned long *delay_on,
426 unsigned long *delay_off,
429 led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
431 EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
433 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
435 struct led_trigger *trig;
438 trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
442 err = led_trigger_register(trig);
446 pr_warn("LED trigger %s failed to register (%d)\n",
450 pr_warn("LED trigger %s failed to register (no memory)\n",
455 EXPORT_SYMBOL_GPL(led_trigger_register_simple);
457 void led_trigger_unregister_simple(struct led_trigger *trig)
460 led_trigger_unregister(trig);
463 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);