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 static 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)
165 if (!led_cdev->trigger && !trig)
168 name = trig ? trig->name : "none";
169 event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
171 /* Remove any existing trigger */
172 if (led_cdev->trigger) {
173 spin_lock(&led_cdev->trigger->leddev_list_lock);
174 list_del_rcu(&led_cdev->trig_list);
175 spin_unlock(&led_cdev->trigger->leddev_list_lock);
177 /* ensure it's no longer visible on the led_cdevs list */
180 cancel_work_sync(&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(led_cdev->dev, 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, LED_OFF);
192 spin_lock(&trig->leddev_list_lock);
193 list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs);
194 spin_unlock(&trig->leddev_list_lock);
195 led_cdev->trigger = trig;
199 ret = trig->activate(led_cdev);
201 led_set_brightness(led_cdev, trig->brightness);
205 ret = device_add_groups(led_cdev->dev, trig->groups);
207 dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
215 if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
216 dev_err(led_cdev->dev,
217 "%s: Error sending uevent\n", __func__);
225 if (trig->deactivate)
226 trig->deactivate(led_cdev);
229 spin_lock(&led_cdev->trigger->leddev_list_lock);
230 list_del_rcu(&led_cdev->trig_list);
231 spin_unlock(&led_cdev->trigger->leddev_list_lock);
233 led_cdev->trigger = NULL;
234 led_cdev->trigger_data = NULL;
235 led_set_brightness(led_cdev, LED_OFF);
240 EXPORT_SYMBOL_GPL(led_trigger_set);
242 void led_trigger_remove(struct led_classdev *led_cdev)
244 down_write(&led_cdev->trigger_lock);
245 led_trigger_set(led_cdev, NULL);
246 up_write(&led_cdev->trigger_lock);
248 EXPORT_SYMBOL_GPL(led_trigger_remove);
250 static bool led_match_default_trigger(struct led_classdev *led_cdev,
251 struct led_trigger *trig)
253 if (!strcmp(led_cdev->default_trigger, trig->name) &&
254 trigger_relevant(led_cdev, trig)) {
255 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
256 led_trigger_set(led_cdev, trig);
263 void led_trigger_set_default(struct led_classdev *led_cdev)
265 struct led_trigger *trig;
268 if (!led_cdev->default_trigger)
271 down_read(&triggers_list_lock);
272 down_write(&led_cdev->trigger_lock);
273 list_for_each_entry(trig, &trigger_list, next_trig) {
274 found = led_match_default_trigger(led_cdev, trig);
278 up_write(&led_cdev->trigger_lock);
279 up_read(&triggers_list_lock);
282 * If default trigger wasn't found, maybe trigger module isn't loaded yet.
283 * Once loaded it will re-probe with all led_cdev's.
286 request_module_nowait("ledtrig:%s", led_cdev->default_trigger);
288 EXPORT_SYMBOL_GPL(led_trigger_set_default);
290 /* LED Trigger Interface */
292 int led_trigger_register(struct led_trigger *trig)
294 struct led_classdev *led_cdev;
295 struct led_trigger *_trig;
297 spin_lock_init(&trig->leddev_list_lock);
298 INIT_LIST_HEAD(&trig->led_cdevs);
300 down_write(&triggers_list_lock);
301 /* Make sure the trigger's name isn't already in use */
302 list_for_each_entry(_trig, &trigger_list, next_trig) {
303 if (!strcmp(_trig->name, trig->name) &&
304 (trig->trigger_type == _trig->trigger_type ||
305 !trig->trigger_type || !_trig->trigger_type)) {
306 up_write(&triggers_list_lock);
310 /* Add to the list of led triggers */
311 list_add_tail(&trig->next_trig, &trigger_list);
312 up_write(&triggers_list_lock);
314 /* Register with any LEDs that have this as a default trigger */
315 down_read(&leds_list_lock);
316 list_for_each_entry(led_cdev, &leds_list, node) {
317 down_write(&led_cdev->trigger_lock);
318 if (!led_cdev->trigger && led_cdev->default_trigger)
319 led_match_default_trigger(led_cdev, trig);
320 up_write(&led_cdev->trigger_lock);
322 up_read(&leds_list_lock);
326 EXPORT_SYMBOL_GPL(led_trigger_register);
328 void led_trigger_unregister(struct led_trigger *trig)
330 struct led_classdev *led_cdev;
332 if (list_empty_careful(&trig->next_trig))
335 /* Remove from the list of led triggers */
336 down_write(&triggers_list_lock);
337 list_del_init(&trig->next_trig);
338 up_write(&triggers_list_lock);
340 /* Remove anyone actively using this trigger */
341 down_read(&leds_list_lock);
342 list_for_each_entry(led_cdev, &leds_list, node) {
343 down_write(&led_cdev->trigger_lock);
344 if (led_cdev->trigger == trig)
345 led_trigger_set(led_cdev, NULL);
346 up_write(&led_cdev->trigger_lock);
348 up_read(&leds_list_lock);
350 EXPORT_SYMBOL_GPL(led_trigger_unregister);
352 static void devm_led_trigger_release(struct device *dev, void *res)
354 led_trigger_unregister(*(struct led_trigger **)res);
357 int devm_led_trigger_register(struct device *dev,
358 struct led_trigger *trig)
360 struct led_trigger **dr;
363 dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
370 rc = led_trigger_register(trig);
378 EXPORT_SYMBOL_GPL(devm_led_trigger_register);
380 /* Simple LED Trigger Interface */
382 void led_trigger_event(struct led_trigger *trig,
383 enum led_brightness brightness)
385 struct led_classdev *led_cdev;
390 trig->brightness = brightness;
393 list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)
394 led_set_brightness(led_cdev, brightness);
397 EXPORT_SYMBOL_GPL(led_trigger_event);
399 static void led_trigger_blink_setup(struct led_trigger *trig,
400 unsigned long delay_on,
401 unsigned long delay_off,
405 struct led_classdev *led_cdev;
411 list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
413 led_blink_set_oneshot(led_cdev, &delay_on, &delay_off,
416 led_blink_set_nosleep(led_cdev, delay_on, delay_off);
421 void led_trigger_blink(struct led_trigger *trig,
422 unsigned long delay_on,
423 unsigned long delay_off)
425 led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
427 EXPORT_SYMBOL_GPL(led_trigger_blink);
429 void led_trigger_blink_oneshot(struct led_trigger *trig,
430 unsigned long delay_on,
431 unsigned long delay_off,
434 led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
436 EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
438 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
440 struct led_trigger *trig;
443 trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
447 err = led_trigger_register(trig);
451 pr_warn("LED trigger %s failed to register (%d)\n",
455 pr_warn("LED trigger %s failed to register (no memory)\n",
460 EXPORT_SYMBOL_GPL(led_trigger_register_simple);
462 void led_trigger_unregister_simple(struct led_trigger *trig)
465 led_trigger_unregister(trig);
468 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);