1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * LED Class Core
4 *
5 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
6 * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
7 */
8
9#include <linux/ctype.h>
10#include <linux/device.h>
11#include <linux/err.h>
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/leds.h>
15#include <linux/list.h>
16#include <linux/module.h>
17#include <linux/property.h>
18#include <linux/slab.h>
19#include <linux/spinlock.h>
20#include <linux/timer.h>
21#include <uapi/linux/uleds.h>
22#include <linux/of.h>
23#include "leds.h"
24
25static DEFINE_MUTEX(leds_lookup_lock);
26static LIST_HEAD(leds_lookup_list);
27
28static ssize_t brightness_show(struct device *dev,
29 struct device_attribute *attr, char *buf)
30{
31 struct led_classdev *led_cdev = dev_get_drvdata(dev);
32
33 /* no lock needed for this */
34 led_update_brightness(led_cdev);
35
36 return sprintf(buf, fmt: "%u\n", led_cdev->brightness);
37}
38
39static ssize_t brightness_store(struct device *dev,
40 struct device_attribute *attr, const char *buf, size_t size)
41{
42 struct led_classdev *led_cdev = dev_get_drvdata(dev);
43 unsigned long state;
44 ssize_t ret;
45
46 mutex_lock(&led_cdev->led_access);
47
48 if (led_sysfs_is_disabled(led_cdev)) {
49 ret = -EBUSY;
50 goto unlock;
51 }
52
53 ret = kstrtoul(s: buf, base: 10, res: &state);
54 if (ret)
55 goto unlock;
56
57 if (state == LED_OFF)
58 led_trigger_remove(led_cdev);
59 led_set_brightness(led_cdev, brightness: state);
60 flush_work(work: &led_cdev->set_brightness_work);
61
62 ret = size;
63unlock:
64 mutex_unlock(lock: &led_cdev->led_access);
65 return ret;
66}
67static DEVICE_ATTR_RW(brightness);
68
69static ssize_t max_brightness_show(struct device *dev,
70 struct device_attribute *attr, char *buf)
71{
72 struct led_classdev *led_cdev = dev_get_drvdata(dev);
73
74 return sprintf(buf, fmt: "%u\n", led_cdev->max_brightness);
75}
76static DEVICE_ATTR_RO(max_brightness);
77
78#ifdef CONFIG_LEDS_TRIGGERS
79static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
80static struct bin_attribute *led_trigger_bin_attrs[] = {
81 &bin_attr_trigger,
82 NULL,
83};
84static const struct attribute_group led_trigger_group = {
85 .bin_attrs = led_trigger_bin_attrs,
86};
87#endif
88
89static struct attribute *led_class_attrs[] = {
90 &dev_attr_brightness.attr,
91 &dev_attr_max_brightness.attr,
92 NULL,
93};
94
95static const struct attribute_group led_group = {
96 .attrs = led_class_attrs,
97};
98
99static const struct attribute_group *led_groups[] = {
100 &led_group,
101#ifdef CONFIG_LEDS_TRIGGERS
102 &led_trigger_group,
103#endif
104 NULL,
105};
106
107#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
108static ssize_t brightness_hw_changed_show(struct device *dev,
109 struct device_attribute *attr, char *buf)
110{
111 struct led_classdev *led_cdev = dev_get_drvdata(dev);
112
113 if (led_cdev->brightness_hw_changed == -1)
114 return -ENODATA;
115
116 return sprintf(buf, fmt: "%u\n", led_cdev->brightness_hw_changed);
117}
118
119static DEVICE_ATTR_RO(brightness_hw_changed);
120
121static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
122{
123 struct device *dev = led_cdev->dev;
124 int ret;
125
126 ret = device_create_file(device: dev, entry: &dev_attr_brightness_hw_changed);
127 if (ret) {
128 dev_err(dev, "Error creating brightness_hw_changed\n");
129 return ret;
130 }
131
132 led_cdev->brightness_hw_changed_kn =
133 sysfs_get_dirent(parent: dev->kobj.sd, name: "brightness_hw_changed");
134 if (!led_cdev->brightness_hw_changed_kn) {
135 dev_err(dev, "Error getting brightness_hw_changed kn\n");
136 device_remove_file(dev, attr: &dev_attr_brightness_hw_changed);
137 return -ENXIO;
138 }
139
140 return 0;
141}
142
143static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
144{
145 sysfs_put(kn: led_cdev->brightness_hw_changed_kn);
146 device_remove_file(dev: led_cdev->dev, attr: &dev_attr_brightness_hw_changed);
147}
148
149void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int brightness)
150{
151 if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
152 return;
153
154 led_cdev->brightness_hw_changed = brightness;
155 sysfs_notify_dirent(kn: led_cdev->brightness_hw_changed_kn);
156}
157EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
158#else
159static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
160{
161 return 0;
162}
163static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
164{
165}
166#endif
167
168/**
169 * led_classdev_suspend - suspend an led_classdev.
170 * @led_cdev: the led_classdev to suspend.
171 */
172void led_classdev_suspend(struct led_classdev *led_cdev)
173{
174 led_cdev->flags |= LED_SUSPENDED;
175 led_set_brightness_nopm(led_cdev, value: 0);
176 flush_work(work: &led_cdev->set_brightness_work);
177}
178EXPORT_SYMBOL_GPL(led_classdev_suspend);
179
180/**
181 * led_classdev_resume - resume an led_classdev.
182 * @led_cdev: the led_classdev to resume.
183 */
184void led_classdev_resume(struct led_classdev *led_cdev)
185{
186 led_set_brightness_nopm(led_cdev, value: led_cdev->brightness);
187
188 if (led_cdev->flash_resume)
189 led_cdev->flash_resume(led_cdev);
190
191 led_cdev->flags &= ~LED_SUSPENDED;
192}
193EXPORT_SYMBOL_GPL(led_classdev_resume);
194
195#ifdef CONFIG_PM_SLEEP
196static int led_suspend(struct device *dev)
197{
198 struct led_classdev *led_cdev = dev_get_drvdata(dev);
199
200 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
201 led_classdev_suspend(led_cdev);
202
203 return 0;
204}
205
206static int led_resume(struct device *dev)
207{
208 struct led_classdev *led_cdev = dev_get_drvdata(dev);
209
210 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
211 led_classdev_resume(led_cdev);
212
213 return 0;
214}
215#endif
216
217static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
218
219static struct led_classdev *led_module_get(struct device *led_dev)
220{
221 struct led_classdev *led_cdev;
222
223 if (!led_dev)
224 return ERR_PTR(error: -EPROBE_DEFER);
225
226 led_cdev = dev_get_drvdata(dev: led_dev);
227
228 if (!try_module_get(module: led_cdev->dev->parent->driver->owner)) {
229 put_device(dev: led_cdev->dev);
230 return ERR_PTR(error: -ENODEV);
231 }
232
233 return led_cdev;
234}
235
236static const struct class leds_class = {
237 .name = "leds",
238 .dev_groups = led_groups,
239 .pm = &leds_class_dev_pm_ops,
240};
241
242/**
243 * of_led_get() - request a LED device via the LED framework
244 * @np: device node to get the LED device from
245 * @index: the index of the LED
246 *
247 * Returns the LED device parsed from the phandle specified in the "leds"
248 * property of a device tree node or a negative error-code on failure.
249 */
250struct led_classdev *of_led_get(struct device_node *np, int index)
251{
252 struct device *led_dev;
253 struct device_node *led_node;
254
255 led_node = of_parse_phandle(np, phandle_name: "leds", index);
256 if (!led_node)
257 return ERR_PTR(error: -ENOENT);
258
259 led_dev = class_find_device_by_of_node(class: &leds_class, np: led_node);
260 of_node_put(node: led_node);
261 put_device(dev: led_dev);
262
263 return led_module_get(led_dev);
264}
265EXPORT_SYMBOL_GPL(of_led_get);
266
267/**
268 * led_put() - release a LED device
269 * @led_cdev: LED device
270 */
271void led_put(struct led_classdev *led_cdev)
272{
273 module_put(module: led_cdev->dev->parent->driver->owner);
274 put_device(dev: led_cdev->dev);
275}
276EXPORT_SYMBOL_GPL(led_put);
277
278static void devm_led_release(struct device *dev, void *res)
279{
280 struct led_classdev **p = res;
281
282 led_put(*p);
283}
284
285static struct led_classdev *__devm_led_get(struct device *dev, struct led_classdev *led)
286{
287 struct led_classdev **dr;
288
289 dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), GFP_KERNEL);
290 if (!dr) {
291 led_put(led);
292 return ERR_PTR(error: -ENOMEM);
293 }
294
295 *dr = led;
296 devres_add(dev, res: dr);
297
298 return led;
299}
300
301/**
302 * devm_of_led_get - Resource-managed request of a LED device
303 * @dev: LED consumer
304 * @index: index of the LED to obtain in the consumer
305 *
306 * The device node of the device is parse to find the request LED device.
307 * The LED device returned from this function is automatically released
308 * on driver detach.
309 *
310 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
311 */
312struct led_classdev *__must_check devm_of_led_get(struct device *dev,
313 int index)
314{
315 struct led_classdev *led;
316
317 if (!dev)
318 return ERR_PTR(error: -EINVAL);
319
320 led = of_led_get(dev->of_node, index);
321 if (IS_ERR(ptr: led))
322 return led;
323
324 return __devm_led_get(dev, led);
325}
326EXPORT_SYMBOL_GPL(devm_of_led_get);
327
328/**
329 * led_get() - request a LED device via the LED framework
330 * @dev: device for which to get the LED device
331 * @con_id: name of the LED from the device's point of view
332 *
333 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
334 */
335struct led_classdev *led_get(struct device *dev, char *con_id)
336{
337 struct led_lookup_data *lookup;
338 const char *provider = NULL;
339 struct device *led_dev;
340
341 mutex_lock(&leds_lookup_lock);
342 list_for_each_entry(lookup, &leds_lookup_list, list) {
343 if (!strcmp(lookup->dev_id, dev_name(dev)) &&
344 !strcmp(lookup->con_id, con_id)) {
345 provider = kstrdup_const(s: lookup->provider, GFP_KERNEL);
346 break;
347 }
348 }
349 mutex_unlock(lock: &leds_lookup_lock);
350
351 if (!provider)
352 return ERR_PTR(error: -ENOENT);
353
354 led_dev = class_find_device_by_name(class: &leds_class, name: provider);
355 kfree_const(x: provider);
356
357 return led_module_get(led_dev);
358}
359EXPORT_SYMBOL_GPL(led_get);
360
361/**
362 * devm_led_get() - request a LED device via the LED framework
363 * @dev: device for which to get the LED device
364 * @con_id: name of the LED from the device's point of view
365 *
366 * The LED device returned from this function is automatically released
367 * on driver detach.
368 *
369 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
370 */
371struct led_classdev *devm_led_get(struct device *dev, char *con_id)
372{
373 struct led_classdev *led;
374
375 led = led_get(dev, con_id);
376 if (IS_ERR(ptr: led))
377 return led;
378
379 return __devm_led_get(dev, led);
380}
381EXPORT_SYMBOL_GPL(devm_led_get);
382
383/**
384 * led_add_lookup() - Add a LED lookup table entry
385 * @led_lookup: the lookup table entry to add
386 *
387 * Add a LED lookup table entry. On systems without devicetree the lookup table
388 * is used by led_get() to find LEDs.
389 */
390void led_add_lookup(struct led_lookup_data *led_lookup)
391{
392 mutex_lock(&leds_lookup_lock);
393 list_add_tail(new: &led_lookup->list, head: &leds_lookup_list);
394 mutex_unlock(lock: &leds_lookup_lock);
395}
396EXPORT_SYMBOL_GPL(led_add_lookup);
397
398/**
399 * led_remove_lookup() - Remove a LED lookup table entry
400 * @led_lookup: the lookup table entry to remove
401 */
402void led_remove_lookup(struct led_lookup_data *led_lookup)
403{
404 mutex_lock(&leds_lookup_lock);
405 list_del(entry: &led_lookup->list);
406 mutex_unlock(lock: &leds_lookup_lock);
407}
408EXPORT_SYMBOL_GPL(led_remove_lookup);
409
410/**
411 * devm_of_led_get_optional - Resource-managed request of an optional LED device
412 * @dev: LED consumer
413 * @index: index of the LED to obtain in the consumer
414 *
415 * The device node of the device is parsed to find the requested LED device.
416 * The LED device returned from this function is automatically released
417 * on driver detach.
418 *
419 * @return a pointer to a LED device, ERR_PTR(errno) on failure and NULL if the
420 * led was not found.
421 */
422struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
423 int index)
424{
425 struct led_classdev *led;
426
427 led = devm_of_led_get(dev, index);
428 if (IS_ERR(ptr: led) && PTR_ERR(ptr: led) == -ENOENT)
429 return NULL;
430
431 return led;
432}
433EXPORT_SYMBOL_GPL(devm_of_led_get_optional);
434
435static int led_classdev_next_name(const char *init_name, char *name,
436 size_t len)
437{
438 unsigned int i = 0;
439 int ret = 0;
440 struct device *dev;
441
442 strscpy(name, init_name, len);
443
444 while ((ret < len) &&
445 (dev = class_find_device_by_name(class: &leds_class, name))) {
446 put_device(dev);
447 ret = snprintf(buf: name, size: len, fmt: "%s_%u", init_name, ++i);
448 }
449
450 if (ret >= len)
451 return -ENOMEM;
452
453 return i;
454}
455
456/**
457 * led_classdev_register_ext - register a new object of led_classdev class
458 * with init data.
459 *
460 * @parent: parent of LED device
461 * @led_cdev: the led_classdev structure for this device.
462 * @init_data: LED class device initialization data
463 */
464int led_classdev_register_ext(struct device *parent,
465 struct led_classdev *led_cdev,
466 struct led_init_data *init_data)
467{
468 char composed_name[LED_MAX_NAME_SIZE];
469 char final_name[LED_MAX_NAME_SIZE];
470 const char *proposed_name = composed_name;
471 int ret;
472
473 if (init_data) {
474 if (init_data->devname_mandatory && !init_data->devicename) {
475 dev_err(parent, "Mandatory device name is missing");
476 return -EINVAL;
477 }
478 ret = led_compose_name(dev: parent, init_data, led_classdev_name: composed_name);
479 if (ret < 0)
480 return ret;
481
482 if (init_data->fwnode) {
483 fwnode_property_read_string(fwnode: init_data->fwnode,
484 propname: "linux,default-trigger",
485 val: &led_cdev->default_trigger);
486
487 if (fwnode_property_present(fwnode: init_data->fwnode,
488 propname: "retain-state-shutdown"))
489 led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
490
491 fwnode_property_read_u32(fwnode: init_data->fwnode,
492 propname: "max-brightness",
493 val: &led_cdev->max_brightness);
494
495 if (fwnode_property_present(fwnode: init_data->fwnode, propname: "color"))
496 fwnode_property_read_u32(fwnode: init_data->fwnode, propname: "color",
497 val: &led_cdev->color);
498 }
499 } else {
500 proposed_name = led_cdev->name;
501 }
502
503 ret = led_classdev_next_name(init_name: proposed_name, name: final_name, len: sizeof(final_name));
504 if (ret < 0)
505 return ret;
506
507 if (led_cdev->color >= LED_COLOR_ID_MAX)
508 dev_warn(parent, "LED %s color identifier out of range\n", final_name);
509
510 mutex_init(&led_cdev->led_access);
511 mutex_lock(&led_cdev->led_access);
512 led_cdev->dev = device_create_with_groups(cls: &leds_class, parent, devt: 0,
513 drvdata: led_cdev, groups: led_cdev->groups, fmt: "%s", final_name);
514 if (IS_ERR(ptr: led_cdev->dev)) {
515 mutex_unlock(lock: &led_cdev->led_access);
516 return PTR_ERR(ptr: led_cdev->dev);
517 }
518 if (init_data && init_data->fwnode)
519 device_set_node(dev: led_cdev->dev, fwnode: init_data->fwnode);
520
521 if (ret)
522 dev_warn(parent, "Led %s renamed to %s due to name collision",
523 proposed_name, dev_name(led_cdev->dev));
524
525 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
526 ret = led_add_brightness_hw_changed(led_cdev);
527 if (ret) {
528 device_unregister(dev: led_cdev->dev);
529 led_cdev->dev = NULL;
530 mutex_unlock(lock: &led_cdev->led_access);
531 return ret;
532 }
533 }
534
535 led_cdev->work_flags = 0;
536#ifdef CONFIG_LEDS_TRIGGERS
537 init_rwsem(&led_cdev->trigger_lock);
538#endif
539#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
540 led_cdev->brightness_hw_changed = -1;
541#endif
542 /* add to the list of leds */
543 down_write(sem: &leds_list_lock);
544 list_add_tail(new: &led_cdev->node, head: &leds_list);
545 up_write(sem: &leds_list_lock);
546
547 if (!led_cdev->max_brightness)
548 led_cdev->max_brightness = LED_FULL;
549
550 led_update_brightness(led_cdev);
551
552 led_init_core(led_cdev);
553
554#ifdef CONFIG_LEDS_TRIGGERS
555 /*
556 * If no default trigger was given and hw_control_trigger is set,
557 * make it the default trigger.
558 */
559 if (!led_cdev->default_trigger && led_cdev->hw_control_trigger)
560 led_cdev->default_trigger = led_cdev->hw_control_trigger;
561 led_trigger_set_default(led_cdev);
562#endif
563
564 mutex_unlock(lock: &led_cdev->led_access);
565
566 dev_dbg(parent, "Registered led device: %s\n",
567 led_cdev->name);
568
569 return 0;
570}
571EXPORT_SYMBOL_GPL(led_classdev_register_ext);
572
573/**
574 * led_classdev_unregister - unregisters a object of led_properties class.
575 * @led_cdev: the led device to unregister
576 *
577 * Unregisters a previously registered via led_classdev_register object.
578 */
579void led_classdev_unregister(struct led_classdev *led_cdev)
580{
581 if (IS_ERR_OR_NULL(ptr: led_cdev->dev))
582 return;
583
584#ifdef CONFIG_LEDS_TRIGGERS
585 down_write(sem: &led_cdev->trigger_lock);
586 if (led_cdev->trigger)
587 led_trigger_set(led_cdev, NULL);
588 up_write(sem: &led_cdev->trigger_lock);
589#endif
590
591 led_cdev->flags |= LED_UNREGISTERING;
592
593 /* Stop blinking */
594 led_stop_software_blink(led_cdev);
595
596 if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
597 led_set_brightness(led_cdev, brightness: LED_OFF);
598
599 flush_work(work: &led_cdev->set_brightness_work);
600
601 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
602 led_remove_brightness_hw_changed(led_cdev);
603
604 device_unregister(dev: led_cdev->dev);
605
606 down_write(sem: &leds_list_lock);
607 list_del(entry: &led_cdev->node);
608 up_write(sem: &leds_list_lock);
609
610 mutex_destroy(lock: &led_cdev->led_access);
611}
612EXPORT_SYMBOL_GPL(led_classdev_unregister);
613
614static void devm_led_classdev_release(struct device *dev, void *res)
615{
616 led_classdev_unregister(*(struct led_classdev **)res);
617}
618
619/**
620 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
621 *
622 * @parent: parent of LED device
623 * @led_cdev: the led_classdev structure for this device.
624 * @init_data: LED class device initialization data
625 */
626int devm_led_classdev_register_ext(struct device *parent,
627 struct led_classdev *led_cdev,
628 struct led_init_data *init_data)
629{
630 struct led_classdev **dr;
631 int rc;
632
633 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
634 if (!dr)
635 return -ENOMEM;
636
637 rc = led_classdev_register_ext(parent, led_cdev, init_data);
638 if (rc) {
639 devres_free(res: dr);
640 return rc;
641 }
642
643 *dr = led_cdev;
644 devres_add(dev: parent, res: dr);
645
646 return 0;
647}
648EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
649
650static int devm_led_classdev_match(struct device *dev, void *res, void *data)
651{
652 struct led_classdev **p = res;
653
654 if (WARN_ON(!p || !*p))
655 return 0;
656
657 return *p == data;
658}
659
660/**
661 * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
662 * @dev: The device to unregister.
663 * @led_cdev: the led_classdev structure for this device.
664 */
665void devm_led_classdev_unregister(struct device *dev,
666 struct led_classdev *led_cdev)
667{
668 WARN_ON(devres_release(dev,
669 devm_led_classdev_release,
670 devm_led_classdev_match, led_cdev));
671}
672EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
673
674static int __init leds_init(void)
675{
676 return class_register(class: &leds_class);
677}
678
679static void __exit leds_exit(void)
680{
681 class_unregister(class: &leds_class);
682}
683
684subsys_initcall(leds_init);
685module_exit(leds_exit);
686
687MODULE_AUTHOR("John Lenz, Richard Purdie");
688MODULE_LICENSE("GPL");
689MODULE_DESCRIPTION("LED Class Interface");
690

source code of linux/drivers/leds/led-class.c