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
78static ssize_t color_show(struct device *dev,
79 struct device_attribute *attr, char *buf)
80{
81 const char *color_text = "invalid";
82 struct led_classdev *led_cdev = dev_get_drvdata(dev);
83
84 if (led_cdev->color < LED_COLOR_ID_MAX)
85 color_text = led_colors[led_cdev->color];
86
87 return sysfs_emit(buf, fmt: "%s\n", color_text);
88}
89static DEVICE_ATTR_RO(color);
90
91#ifdef CONFIG_LEDS_TRIGGERS
92static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
93static struct bin_attribute *led_trigger_bin_attrs[] = {
94 &bin_attr_trigger,
95 NULL,
96};
97static const struct attribute_group led_trigger_group = {
98 .bin_attrs = led_trigger_bin_attrs,
99};
100#endif
101
102static struct attribute *led_class_attrs[] = {
103 &dev_attr_brightness.attr,
104 &dev_attr_max_brightness.attr,
105 &dev_attr_color.attr,
106 NULL,
107};
108
109static const struct attribute_group led_group = {
110 .attrs = led_class_attrs,
111};
112
113static const struct attribute_group *led_groups[] = {
114 &led_group,
115#ifdef CONFIG_LEDS_TRIGGERS
116 &led_trigger_group,
117#endif
118 NULL,
119};
120
121#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
122static ssize_t brightness_hw_changed_show(struct device *dev,
123 struct device_attribute *attr, char *buf)
124{
125 struct led_classdev *led_cdev = dev_get_drvdata(dev);
126
127 if (led_cdev->brightness_hw_changed == -1)
128 return -ENODATA;
129
130 return sprintf(buf, fmt: "%u\n", led_cdev->brightness_hw_changed);
131}
132
133static DEVICE_ATTR_RO(brightness_hw_changed);
134
135static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
136{
137 struct device *dev = led_cdev->dev;
138 int ret;
139
140 ret = device_create_file(device: dev, entry: &dev_attr_brightness_hw_changed);
141 if (ret) {
142 dev_err(dev, "Error creating brightness_hw_changed\n");
143 return ret;
144 }
145
146 led_cdev->brightness_hw_changed_kn =
147 sysfs_get_dirent(parent: dev->kobj.sd, name: "brightness_hw_changed");
148 if (!led_cdev->brightness_hw_changed_kn) {
149 dev_err(dev, "Error getting brightness_hw_changed kn\n");
150 device_remove_file(dev, attr: &dev_attr_brightness_hw_changed);
151 return -ENXIO;
152 }
153
154 return 0;
155}
156
157static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
158{
159 sysfs_put(kn: led_cdev->brightness_hw_changed_kn);
160 device_remove_file(dev: led_cdev->dev, attr: &dev_attr_brightness_hw_changed);
161}
162
163void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int brightness)
164{
165 if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
166 return;
167
168 led_cdev->brightness_hw_changed = brightness;
169 sysfs_notify_dirent(kn: led_cdev->brightness_hw_changed_kn);
170}
171EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
172#else
173static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
174{
175 return 0;
176}
177static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
178{
179}
180#endif
181
182/**
183 * led_classdev_suspend - suspend an led_classdev.
184 * @led_cdev: the led_classdev to suspend.
185 */
186void led_classdev_suspend(struct led_classdev *led_cdev)
187{
188 led_cdev->flags |= LED_SUSPENDED;
189 led_set_brightness_nopm(led_cdev, value: 0);
190 flush_work(work: &led_cdev->set_brightness_work);
191}
192EXPORT_SYMBOL_GPL(led_classdev_suspend);
193
194/**
195 * led_classdev_resume - resume an led_classdev.
196 * @led_cdev: the led_classdev to resume.
197 */
198void led_classdev_resume(struct led_classdev *led_cdev)
199{
200 led_set_brightness_nopm(led_cdev, value: led_cdev->brightness);
201
202 if (led_cdev->flash_resume)
203 led_cdev->flash_resume(led_cdev);
204
205 led_cdev->flags &= ~LED_SUSPENDED;
206}
207EXPORT_SYMBOL_GPL(led_classdev_resume);
208
209#ifdef CONFIG_PM_SLEEP
210static int led_suspend(struct device *dev)
211{
212 struct led_classdev *led_cdev = dev_get_drvdata(dev);
213
214 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
215 led_classdev_suspend(led_cdev);
216
217 return 0;
218}
219
220static int led_resume(struct device *dev)
221{
222 struct led_classdev *led_cdev = dev_get_drvdata(dev);
223
224 if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
225 led_classdev_resume(led_cdev);
226
227 return 0;
228}
229#endif
230
231static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
232
233static struct led_classdev *led_module_get(struct device *led_dev)
234{
235 struct led_classdev *led_cdev;
236
237 if (!led_dev)
238 return ERR_PTR(error: -EPROBE_DEFER);
239
240 led_cdev = dev_get_drvdata(dev: led_dev);
241
242 if (!try_module_get(module: led_cdev->dev->parent->driver->owner)) {
243 put_device(dev: led_cdev->dev);
244 return ERR_PTR(error: -ENODEV);
245 }
246
247 return led_cdev;
248}
249
250static const struct class leds_class = {
251 .name = "leds",
252 .dev_groups = led_groups,
253 .pm = &leds_class_dev_pm_ops,
254};
255
256/**
257 * of_led_get() - request a LED device via the LED framework
258 * @np: device node to get the LED device from
259 * @index: the index of the LED
260 *
261 * Returns the LED device parsed from the phandle specified in the "leds"
262 * property of a device tree node or a negative error-code on failure.
263 */
264struct led_classdev *of_led_get(struct device_node *np, int index)
265{
266 struct device *led_dev;
267 struct device_node *led_node;
268
269 led_node = of_parse_phandle(np, phandle_name: "leds", index);
270 if (!led_node)
271 return ERR_PTR(error: -ENOENT);
272
273 led_dev = class_find_device_by_of_node(class: &leds_class, np: led_node);
274 of_node_put(node: led_node);
275 put_device(dev: led_dev);
276
277 return led_module_get(led_dev);
278}
279EXPORT_SYMBOL_GPL(of_led_get);
280
281/**
282 * led_put() - release a LED device
283 * @led_cdev: LED device
284 */
285void led_put(struct led_classdev *led_cdev)
286{
287 module_put(module: led_cdev->dev->parent->driver->owner);
288 put_device(dev: led_cdev->dev);
289}
290EXPORT_SYMBOL_GPL(led_put);
291
292static void devm_led_release(struct device *dev, void *res)
293{
294 struct led_classdev **p = res;
295
296 led_put(*p);
297}
298
299static struct led_classdev *__devm_led_get(struct device *dev, struct led_classdev *led)
300{
301 struct led_classdev **dr;
302
303 dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), GFP_KERNEL);
304 if (!dr) {
305 led_put(led);
306 return ERR_PTR(error: -ENOMEM);
307 }
308
309 *dr = led;
310 devres_add(dev, res: dr);
311
312 return led;
313}
314
315/**
316 * devm_of_led_get - Resource-managed request of a LED device
317 * @dev: LED consumer
318 * @index: index of the LED to obtain in the consumer
319 *
320 * The device node of the device is parse to find the request LED device.
321 * The LED device returned from this function is automatically released
322 * on driver detach.
323 *
324 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
325 */
326struct led_classdev *__must_check devm_of_led_get(struct device *dev,
327 int index)
328{
329 struct led_classdev *led;
330
331 if (!dev)
332 return ERR_PTR(error: -EINVAL);
333
334 led = of_led_get(dev->of_node, index);
335 if (IS_ERR(ptr: led))
336 return led;
337
338 return __devm_led_get(dev, led);
339}
340EXPORT_SYMBOL_GPL(devm_of_led_get);
341
342/**
343 * led_get() - request a LED device via the LED framework
344 * @dev: device for which to get the LED device
345 * @con_id: name of the LED from the device's point of view
346 *
347 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
348 */
349struct led_classdev *led_get(struct device *dev, char *con_id)
350{
351 struct led_lookup_data *lookup;
352 const char *provider = NULL;
353 struct device *led_dev;
354
355 mutex_lock(&leds_lookup_lock);
356 list_for_each_entry(lookup, &leds_lookup_list, list) {
357 if (!strcmp(lookup->dev_id, dev_name(dev)) &&
358 !strcmp(lookup->con_id, con_id)) {
359 provider = kstrdup_const(s: lookup->provider, GFP_KERNEL);
360 break;
361 }
362 }
363 mutex_unlock(lock: &leds_lookup_lock);
364
365 if (!provider)
366 return ERR_PTR(error: -ENOENT);
367
368 led_dev = class_find_device_by_name(class: &leds_class, name: provider);
369 kfree_const(x: provider);
370
371 return led_module_get(led_dev);
372}
373EXPORT_SYMBOL_GPL(led_get);
374
375/**
376 * devm_led_get() - request a LED device via the LED framework
377 * @dev: device for which to get the LED device
378 * @con_id: name of the LED from the device's point of view
379 *
380 * The LED device returned from this function is automatically released
381 * on driver detach.
382 *
383 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
384 */
385struct led_classdev *devm_led_get(struct device *dev, char *con_id)
386{
387 struct led_classdev *led;
388
389 led = led_get(dev, con_id);
390 if (IS_ERR(ptr: led))
391 return led;
392
393 return __devm_led_get(dev, led);
394}
395EXPORT_SYMBOL_GPL(devm_led_get);
396
397/**
398 * led_add_lookup() - Add a LED lookup table entry
399 * @led_lookup: the lookup table entry to add
400 *
401 * Add a LED lookup table entry. On systems without devicetree the lookup table
402 * is used by led_get() to find LEDs.
403 */
404void led_add_lookup(struct led_lookup_data *led_lookup)
405{
406 mutex_lock(&leds_lookup_lock);
407 list_add_tail(new: &led_lookup->list, head: &leds_lookup_list);
408 mutex_unlock(lock: &leds_lookup_lock);
409}
410EXPORT_SYMBOL_GPL(led_add_lookup);
411
412/**
413 * led_remove_lookup() - Remove a LED lookup table entry
414 * @led_lookup: the lookup table entry to remove
415 */
416void led_remove_lookup(struct led_lookup_data *led_lookup)
417{
418 mutex_lock(&leds_lookup_lock);
419 list_del(entry: &led_lookup->list);
420 mutex_unlock(lock: &leds_lookup_lock);
421}
422EXPORT_SYMBOL_GPL(led_remove_lookup);
423
424/**
425 * devm_of_led_get_optional - Resource-managed request of an optional LED device
426 * @dev: LED consumer
427 * @index: index of the LED to obtain in the consumer
428 *
429 * The device node of the device is parsed to find the requested LED device.
430 * The LED device returned from this function is automatically released
431 * on driver detach.
432 *
433 * @return a pointer to a LED device, ERR_PTR(errno) on failure and NULL if the
434 * led was not found.
435 */
436struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
437 int index)
438{
439 struct led_classdev *led;
440
441 led = devm_of_led_get(dev, index);
442 if (IS_ERR(ptr: led) && PTR_ERR(ptr: led) == -ENOENT)
443 return NULL;
444
445 return led;
446}
447EXPORT_SYMBOL_GPL(devm_of_led_get_optional);
448
449static int led_classdev_next_name(const char *init_name, char *name,
450 size_t len)
451{
452 unsigned int i = 0;
453 int ret = 0;
454 struct device *dev;
455
456 strscpy(p: name, q: init_name, size: len);
457
458 while ((ret < len) &&
459 (dev = class_find_device_by_name(class: &leds_class, name))) {
460 put_device(dev);
461 ret = snprintf(buf: name, size: len, fmt: "%s_%u", init_name, ++i);
462 }
463
464 if (ret >= len)
465 return -ENOMEM;
466
467 return i;
468}
469
470/**
471 * led_classdev_register_ext - register a new object of led_classdev class
472 * with init data.
473 *
474 * @parent: parent of LED device
475 * @led_cdev: the led_classdev structure for this device.
476 * @init_data: LED class device initialization data
477 */
478int led_classdev_register_ext(struct device *parent,
479 struct led_classdev *led_cdev,
480 struct led_init_data *init_data)
481{
482 char composed_name[LED_MAX_NAME_SIZE];
483 char final_name[LED_MAX_NAME_SIZE];
484 const char *proposed_name = composed_name;
485 int ret;
486
487 if (init_data) {
488 if (init_data->devname_mandatory && !init_data->devicename) {
489 dev_err(parent, "Mandatory device name is missing");
490 return -EINVAL;
491 }
492 ret = led_compose_name(dev: parent, init_data, led_classdev_name: composed_name);
493 if (ret < 0)
494 return ret;
495
496 if (init_data->fwnode) {
497 fwnode_property_read_string(fwnode: init_data->fwnode,
498 propname: "linux,default-trigger",
499 val: &led_cdev->default_trigger);
500
501 if (fwnode_property_present(fwnode: init_data->fwnode,
502 propname: "retain-state-shutdown"))
503 led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
504
505 fwnode_property_read_u32(fwnode: init_data->fwnode,
506 propname: "max-brightness",
507 val: &led_cdev->max_brightness);
508
509 if (fwnode_property_present(fwnode: init_data->fwnode, propname: "color"))
510 fwnode_property_read_u32(fwnode: init_data->fwnode, propname: "color",
511 val: &led_cdev->color);
512 }
513 } else {
514 proposed_name = led_cdev->name;
515 }
516
517 ret = led_classdev_next_name(init_name: proposed_name, name: final_name, len: sizeof(final_name));
518 if (ret < 0)
519 return ret;
520
521 if (led_cdev->color >= LED_COLOR_ID_MAX)
522 dev_warn(parent, "LED %s color identifier out of range\n", final_name);
523
524 mutex_init(&led_cdev->led_access);
525 mutex_lock(&led_cdev->led_access);
526 led_cdev->dev = device_create_with_groups(cls: &leds_class, parent, devt: 0,
527 drvdata: led_cdev, groups: led_cdev->groups, fmt: "%s", final_name);
528 if (IS_ERR(ptr: led_cdev->dev)) {
529 mutex_unlock(lock: &led_cdev->led_access);
530 return PTR_ERR(ptr: led_cdev->dev);
531 }
532 if (init_data && init_data->fwnode)
533 device_set_node(dev: led_cdev->dev, fwnode: init_data->fwnode);
534
535 if (ret)
536 dev_warn(parent, "Led %s renamed to %s due to name collision",
537 proposed_name, dev_name(led_cdev->dev));
538
539 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
540 ret = led_add_brightness_hw_changed(led_cdev);
541 if (ret) {
542 device_unregister(dev: led_cdev->dev);
543 led_cdev->dev = NULL;
544 mutex_unlock(lock: &led_cdev->led_access);
545 return ret;
546 }
547 }
548
549 led_cdev->work_flags = 0;
550#ifdef CONFIG_LEDS_TRIGGERS
551 init_rwsem(&led_cdev->trigger_lock);
552#endif
553#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
554 led_cdev->brightness_hw_changed = -1;
555#endif
556 /* add to the list of leds */
557 down_write(sem: &leds_list_lock);
558 list_add_tail(new: &led_cdev->node, head: &leds_list);
559 up_write(sem: &leds_list_lock);
560
561 if (!led_cdev->max_brightness)
562 led_cdev->max_brightness = LED_FULL;
563
564 led_update_brightness(led_cdev);
565
566 led_init_core(led_cdev);
567
568#ifdef CONFIG_LEDS_TRIGGERS
569 led_trigger_set_default(led_cdev);
570#endif
571
572 mutex_unlock(lock: &led_cdev->led_access);
573
574 dev_dbg(parent, "Registered led device: %s\n",
575 led_cdev->name);
576
577 return 0;
578}
579EXPORT_SYMBOL_GPL(led_classdev_register_ext);
580
581/**
582 * led_classdev_unregister - unregisters a object of led_properties class.
583 * @led_cdev: the led device to unregister
584 *
585 * Unregisters a previously registered via led_classdev_register object.
586 */
587void led_classdev_unregister(struct led_classdev *led_cdev)
588{
589 if (IS_ERR_OR_NULL(ptr: led_cdev->dev))
590 return;
591
592#ifdef CONFIG_LEDS_TRIGGERS
593 down_write(sem: &led_cdev->trigger_lock);
594 if (led_cdev->trigger)
595 led_trigger_set(led_cdev, NULL);
596 up_write(sem: &led_cdev->trigger_lock);
597#endif
598
599 led_cdev->flags |= LED_UNREGISTERING;
600
601 /* Stop blinking */
602 led_stop_software_blink(led_cdev);
603
604 if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
605 led_set_brightness(led_cdev, brightness: LED_OFF);
606
607 flush_work(work: &led_cdev->set_brightness_work);
608
609 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
610 led_remove_brightness_hw_changed(led_cdev);
611
612 device_unregister(dev: led_cdev->dev);
613
614 down_write(sem: &leds_list_lock);
615 list_del(entry: &led_cdev->node);
616 up_write(sem: &leds_list_lock);
617
618 mutex_destroy(lock: &led_cdev->led_access);
619}
620EXPORT_SYMBOL_GPL(led_classdev_unregister);
621
622static void devm_led_classdev_release(struct device *dev, void *res)
623{
624 led_classdev_unregister(*(struct led_classdev **)res);
625}
626
627/**
628 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
629 *
630 * @parent: parent of LED device
631 * @led_cdev: the led_classdev structure for this device.
632 * @init_data: LED class device initialization data
633 */
634int devm_led_classdev_register_ext(struct device *parent,
635 struct led_classdev *led_cdev,
636 struct led_init_data *init_data)
637{
638 struct led_classdev **dr;
639 int rc;
640
641 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
642 if (!dr)
643 return -ENOMEM;
644
645 rc = led_classdev_register_ext(parent, led_cdev, init_data);
646 if (rc) {
647 devres_free(res: dr);
648 return rc;
649 }
650
651 *dr = led_cdev;
652 devres_add(dev: parent, res: dr);
653
654 return 0;
655}
656EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
657
658static int devm_led_classdev_match(struct device *dev, void *res, void *data)
659{
660 struct led_classdev **p = res;
661
662 if (WARN_ON(!p || !*p))
663 return 0;
664
665 return *p == data;
666}
667
668/**
669 * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
670 * @dev: The device to unregister.
671 * @led_cdev: the led_classdev structure for this device.
672 */
673void devm_led_classdev_unregister(struct device *dev,
674 struct led_classdev *led_cdev)
675{
676 WARN_ON(devres_release(dev,
677 devm_led_classdev_release,
678 devm_led_classdev_match, led_cdev));
679}
680EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
681
682static int __init leds_init(void)
683{
684 return class_register(class: &leds_class);
685}
686
687static void __exit leds_exit(void)
688{
689 class_unregister(class: &leds_class);
690}
691
692subsys_initcall(leds_init);
693module_exit(leds_exit);
694
695MODULE_AUTHOR("John Lenz, Richard Purdie");
696MODULE_LICENSE("GPL");
697MODULE_DESCRIPTION("LED Class Interface");
698

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