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>
22 * Nests outside led_cdev->trigger_lock
24 static DECLARE_RWSEM(triggers_list_lock);
25 LIST_HEAD(trigger_list);
27 /* Used by LED Class */
29 ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
30 const char *buf, size_t count)
32 struct led_classdev *led_cdev = dev_get_drvdata(dev);
33 struct led_trigger *trig;
36 mutex_lock(&led_cdev->led_access);
38 if (led_sysfs_is_disabled(led_cdev)) {
43 if (sysfs_streq(buf, "none")) {
44 led_trigger_remove(led_cdev);
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);
55 up_read(&triggers_list_lock);
59 /* we come here only if buf matches no trigger */
61 up_read(&triggers_list_lock);
64 mutex_unlock(&led_cdev->led_access);
67 EXPORT_SYMBOL_GPL(led_trigger_store);
69 ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
72 struct led_classdev *led_cdev = dev_get_drvdata(dev);
73 struct led_trigger *trig;
76 down_read(&triggers_list_lock);
77 down_read(&led_cdev->trigger_lock);
79 if (!led_cdev->trigger)
80 len += scnprintf(buf+len, PAGE_SIZE - len, "[none] ");
82 len += scnprintf(buf+len, PAGE_SIZE - len, "none ");
84 list_for_each_entry(trig, &trigger_list, next_trig) {
85 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
87 len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ",
90 len += scnprintf(buf+len, PAGE_SIZE - len, "%s ",
93 up_read(&led_cdev->trigger_lock);
94 up_read(&triggers_list_lock);
96 len += scnprintf(len+buf, PAGE_SIZE - len, "\n");
99 EXPORT_SYMBOL_GPL(led_trigger_show);
101 /* Caller must ensure led_cdev->trigger_lock held */
102 int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
110 if (!led_cdev->trigger && !trig)
113 name = trig ? trig->name : "none";
114 event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
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,
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);
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;
139 ret = trig->activate(led_cdev);
146 ret = device_add_groups(led_cdev->dev, trig->groups);
148 dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
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__);
166 if (trig->deactivate)
167 trig->deactivate(led_cdev);
170 led_cdev->trigger = NULL;
171 led_cdev->trigger_data = NULL;
172 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
173 list_del(&led_cdev->trig_list);
174 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
175 led_set_brightness(led_cdev, LED_OFF);
179 EXPORT_SYMBOL_GPL(led_trigger_set);
181 void led_trigger_remove(struct led_classdev *led_cdev)
183 down_write(&led_cdev->trigger_lock);
184 led_trigger_set(led_cdev, NULL);
185 up_write(&led_cdev->trigger_lock);
187 EXPORT_SYMBOL_GPL(led_trigger_remove);
189 void led_trigger_set_default(struct led_classdev *led_cdev)
191 struct led_trigger *trig;
193 if (!led_cdev->default_trigger)
196 down_read(&triggers_list_lock);
197 down_write(&led_cdev->trigger_lock);
198 list_for_each_entry(trig, &trigger_list, next_trig) {
199 if (!strcmp(led_cdev->default_trigger, trig->name)) {
200 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
201 led_trigger_set(led_cdev, trig);
205 up_write(&led_cdev->trigger_lock);
206 up_read(&triggers_list_lock);
208 EXPORT_SYMBOL_GPL(led_trigger_set_default);
210 void led_trigger_rename_static(const char *name, struct led_trigger *trig)
212 /* new name must be on a temporary string to prevent races */
213 BUG_ON(name == trig->name);
215 down_write(&triggers_list_lock);
216 /* this assumes that trig->name was originaly allocated to
217 * non constant storage */
218 strcpy((char *)trig->name, name);
219 up_write(&triggers_list_lock);
221 EXPORT_SYMBOL_GPL(led_trigger_rename_static);
223 /* LED Trigger Interface */
225 int led_trigger_register(struct led_trigger *trig)
227 struct led_classdev *led_cdev;
228 struct led_trigger *_trig;
230 rwlock_init(&trig->leddev_list_lock);
231 INIT_LIST_HEAD(&trig->led_cdevs);
233 down_write(&triggers_list_lock);
234 /* Make sure the trigger's name isn't already in use */
235 list_for_each_entry(_trig, &trigger_list, next_trig) {
236 if (!strcmp(_trig->name, trig->name)) {
237 up_write(&triggers_list_lock);
241 /* Add to the list of led triggers */
242 list_add_tail(&trig->next_trig, &trigger_list);
243 up_write(&triggers_list_lock);
245 /* Register with any LEDs that have this as a default trigger */
246 down_read(&leds_list_lock);
247 list_for_each_entry(led_cdev, &leds_list, node) {
248 down_write(&led_cdev->trigger_lock);
249 if (!led_cdev->trigger && led_cdev->default_trigger &&
250 !strcmp(led_cdev->default_trigger, trig->name)) {
251 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
252 led_trigger_set(led_cdev, trig);
254 up_write(&led_cdev->trigger_lock);
256 up_read(&leds_list_lock);
260 EXPORT_SYMBOL_GPL(led_trigger_register);
262 void led_trigger_unregister(struct led_trigger *trig)
264 struct led_classdev *led_cdev;
266 if (list_empty_careful(&trig->next_trig))
269 /* Remove from the list of led triggers */
270 down_write(&triggers_list_lock);
271 list_del_init(&trig->next_trig);
272 up_write(&triggers_list_lock);
274 /* Remove anyone actively using this trigger */
275 down_read(&leds_list_lock);
276 list_for_each_entry(led_cdev, &leds_list, node) {
277 down_write(&led_cdev->trigger_lock);
278 if (led_cdev->trigger == trig)
279 led_trigger_set(led_cdev, NULL);
280 up_write(&led_cdev->trigger_lock);
282 up_read(&leds_list_lock);
284 EXPORT_SYMBOL_GPL(led_trigger_unregister);
286 static void devm_led_trigger_release(struct device *dev, void *res)
288 led_trigger_unregister(*(struct led_trigger **)res);
291 int devm_led_trigger_register(struct device *dev,
292 struct led_trigger *trig)
294 struct led_trigger **dr;
297 dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
304 rc = led_trigger_register(trig);
312 EXPORT_SYMBOL_GPL(devm_led_trigger_register);
314 /* Simple LED Tigger Interface */
316 void led_trigger_event(struct led_trigger *trig,
317 enum led_brightness brightness)
319 struct led_classdev *led_cdev;
324 read_lock(&trig->leddev_list_lock);
325 list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
326 led_set_brightness(led_cdev, brightness);
327 read_unlock(&trig->leddev_list_lock);
329 EXPORT_SYMBOL_GPL(led_trigger_event);
331 static void led_trigger_blink_setup(struct led_trigger *trig,
332 unsigned long *delay_on,
333 unsigned long *delay_off,
337 struct led_classdev *led_cdev;
342 read_lock(&trig->leddev_list_lock);
343 list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
345 led_blink_set_oneshot(led_cdev, delay_on, delay_off,
348 led_blink_set(led_cdev, delay_on, delay_off);
350 read_unlock(&trig->leddev_list_lock);
353 void led_trigger_blink(struct led_trigger *trig,
354 unsigned long *delay_on,
355 unsigned long *delay_off)
357 led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
359 EXPORT_SYMBOL_GPL(led_trigger_blink);
361 void led_trigger_blink_oneshot(struct led_trigger *trig,
362 unsigned long *delay_on,
363 unsigned long *delay_off,
366 led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
368 EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
370 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
372 struct led_trigger *trig;
375 trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
379 err = led_trigger_register(trig);
383 pr_warn("LED trigger %s failed to register (%d)\n",
387 pr_warn("LED trigger %s failed to register (no memory)\n",
392 EXPORT_SYMBOL_GPL(led_trigger_register_simple);
394 void led_trigger_unregister_simple(struct led_trigger *trig)
397 led_trigger_unregister(trig);
400 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);