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 struct class *leds_class;
26
27static ssize_t brightness_show(struct device *dev,
28		struct device_attribute *attr, char *buf)
29{
30	struct led_classdev *led_cdev = dev_get_drvdata(dev);
31
32	/* no lock needed for this */
33	led_update_brightness(led_cdev);
34
35	return sprintf(buf, "%u\n", led_cdev->brightness);
36}
37
38static ssize_t brightness_store(struct device *dev,
39		struct device_attribute *attr, const char *buf, size_t size)
40{
41	struct led_classdev *led_cdev = dev_get_drvdata(dev);
42	unsigned long state;
43	ssize_t ret;
44
45	mutex_lock(&led_cdev->led_access);
46
47	if (led_sysfs_is_disabled(led_cdev)) {
48		ret = -EBUSY;
49		goto unlock;
50	}
51
52	ret = kstrtoul(buf, 10, &state);
53	if (ret)
54		goto unlock;
55
56	if (state == LED_OFF)
57		led_trigger_remove(led_cdev);
58	led_set_brightness(led_cdev, state);
59	flush_work(&led_cdev->set_brightness_work);
60
61	ret = size;
62unlock:
63	mutex_unlock(&led_cdev->led_access);
64	return ret;
65}
66static DEVICE_ATTR_RW(brightness);
67
68static ssize_t max_brightness_show(struct device *dev,
69		struct device_attribute *attr, char *buf)
70{
71	struct led_classdev *led_cdev = dev_get_drvdata(dev);
72
73	return sprintf(buf, "%u\n", led_cdev->max_brightness);
74}
75static DEVICE_ATTR_RO(max_brightness);
76
77#ifdef CONFIG_LEDS_TRIGGERS
78static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
79static struct bin_attribute *led_trigger_bin_attrs[] = {
80	&bin_attr_trigger,
81	NULL,
82};
83static const struct attribute_group led_trigger_group = {
84	.bin_attrs = led_trigger_bin_attrs,
85};
86#endif
87
88static struct attribute *led_class_attrs[] = {
89	&dev_attr_brightness.attr,
90	&dev_attr_max_brightness.attr,
91	NULL,
92};
93
94static const struct attribute_group led_group = {
95	.attrs = led_class_attrs,
96};
97
98static const struct attribute_group *led_groups[] = {
99	&led_group,
100#ifdef CONFIG_LEDS_TRIGGERS
101	&led_trigger_group,
102#endif
103	NULL,
104};
105
106#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
107static ssize_t brightness_hw_changed_show(struct device *dev,
108		struct device_attribute *attr, char *buf)
109{
110	struct led_classdev *led_cdev = dev_get_drvdata(dev);
111
112	if (led_cdev->brightness_hw_changed == -1)
113		return -ENODATA;
114
115	return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
116}
117
118static DEVICE_ATTR_RO(brightness_hw_changed);
119
120static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
121{
122	struct device *dev = led_cdev->dev;
123	int ret;
124
125	ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
126	if (ret) {
127		dev_err(dev, "Error creating brightness_hw_changed\n");
128		return ret;
129	}
130
131	led_cdev->brightness_hw_changed_kn =
132		sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
133	if (!led_cdev->brightness_hw_changed_kn) {
134		dev_err(dev, "Error getting brightness_hw_changed kn\n");
135		device_remove_file(dev, &dev_attr_brightness_hw_changed);
136		return -ENXIO;
137	}
138
139	return 0;
140}
141
142static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
143{
144	sysfs_put(led_cdev->brightness_hw_changed_kn);
145	device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
146}
147
148void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev,
149					       enum led_brightness 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(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, 0);
176	flush_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, 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
219/**
220 * of_led_get() - request a LED device via the LED framework
221 * @np: device node to get the LED device from
222 * @index: the index of the LED
223 *
224 * Returns the LED device parsed from the phandle specified in the "leds"
225 * property of a device tree node or a negative error-code on failure.
226 */
227struct led_classdev *of_led_get(struct device_node *np, int index)
228{
229	struct device *led_dev;
230	struct led_classdev *led_cdev;
231	struct device_node *led_node;
232
233	led_node = of_parse_phandle(np, "leds", index);
234	if (!led_node)
235		return ERR_PTR(-ENOENT);
236
237	led_dev = class_find_device_by_of_node(leds_class, led_node);
238	of_node_put(led_node);
239	put_device(led_dev);
240
241	if (!led_dev)
242		return ERR_PTR(-EPROBE_DEFER);
243
244	led_cdev = dev_get_drvdata(led_dev);
245
246	if (!try_module_get(led_cdev->dev->parent->driver->owner)) {
247		put_device(led_cdev->dev);
248		return ERR_PTR(-ENODEV);
249	}
250
251	return led_cdev;
252}
253EXPORT_SYMBOL_GPL(of_led_get);
254
255/**
256 * led_put() - release a LED device
257 * @led_cdev: LED device
258 */
259void led_put(struct led_classdev *led_cdev)
260{
261	module_put(led_cdev->dev->parent->driver->owner);
262	put_device(led_cdev->dev);
263}
264EXPORT_SYMBOL_GPL(led_put);
265
266static void devm_led_release(struct device *dev, void *res)
267{
268	struct led_classdev **p = res;
269
270	led_put(*p);
271}
272
273/**
274 * devm_of_led_get - Resource-managed request of a LED device
275 * @dev:	LED consumer
276 * @index:	index of the LED to obtain in the consumer
277 *
278 * The device node of the device is parse to find the request LED device.
279 * The LED device returned from this function is automatically released
280 * on driver detach.
281 *
282 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
283 */
284struct led_classdev *__must_check devm_of_led_get(struct device *dev,
285						  int index)
286{
287	struct led_classdev *led;
288	struct led_classdev **dr;
289
290	if (!dev)
291		return ERR_PTR(-EINVAL);
292
293	led = of_led_get(dev->of_node, index);
294	if (IS_ERR(led))
295		return led;
296
297	dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
298			  GFP_KERNEL);
299	if (!dr) {
300		led_put(led);
301		return ERR_PTR(-ENOMEM);
302	}
303
304	*dr = led;
305	devres_add(dev, dr);
306
307	return led;
308}
309EXPORT_SYMBOL_GPL(devm_of_led_get);
310
311static int led_classdev_next_name(const char *init_name, char *name,
312				  size_t len)
313{
314	unsigned int i = 0;
315	int ret = 0;
316	struct device *dev;
317
318	strlcpy(name, init_name, len);
319
320	while ((ret < len) &&
321	       (dev = class_find_device_by_name(leds_class, name))) {
322		put_device(dev);
323		ret = snprintf(name, len, "%s_%u", init_name, ++i);
324	}
325
326	if (ret >= len)
327		return -ENOMEM;
328
329	return i;
330}
331
332/**
333 * led_classdev_register_ext - register a new object of led_classdev class
334 *			       with init data.
335 *
336 * @parent: parent of LED device
337 * @led_cdev: the led_classdev structure for this device.
338 * @init_data: LED class device initialization data
339 */
340int led_classdev_register_ext(struct device *parent,
341			      struct led_classdev *led_cdev,
342			      struct led_init_data *init_data)
343{
344	char composed_name[LED_MAX_NAME_SIZE];
345	char final_name[LED_MAX_NAME_SIZE];
346	const char *proposed_name = composed_name;
347	int ret;
348
349	if (init_data) {
350		if (init_data->devname_mandatory && !init_data->devicename) {
351			dev_err(parent, "Mandatory device name is missing");
352			return -EINVAL;
353		}
354		ret = led_compose_name(parent, init_data, composed_name);
355		if (ret < 0)
356			return ret;
357
358		if (init_data->fwnode)
359			fwnode_property_read_string(init_data->fwnode,
360				"linux,default-trigger",
361				&led_cdev->default_trigger);
362	} else {
363		proposed_name = led_cdev->name;
364	}
365
366	ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
367	if (ret < 0)
368		return ret;
369
370	mutex_init(&led_cdev->led_access);
371	mutex_lock(&led_cdev->led_access);
372	led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
373				led_cdev, led_cdev->groups, "%s", final_name);
374	if (IS_ERR(led_cdev->dev)) {
375		mutex_unlock(&led_cdev->led_access);
376		return PTR_ERR(led_cdev->dev);
377	}
378	if (init_data && init_data->fwnode) {
379		led_cdev->dev->fwnode = init_data->fwnode;
380		led_cdev->dev->of_node = to_of_node(init_data->fwnode);
381	}
382
383	if (ret)
384		dev_warn(parent, "Led %s renamed to %s due to name collision",
385				proposed_name, dev_name(led_cdev->dev));
386
387	if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
388		ret = led_add_brightness_hw_changed(led_cdev);
389		if (ret) {
390			device_unregister(led_cdev->dev);
391			led_cdev->dev = NULL;
392			mutex_unlock(&led_cdev->led_access);
393			return ret;
394		}
395	}
396
397	led_cdev->work_flags = 0;
398#ifdef CONFIG_LEDS_TRIGGERS
399	init_rwsem(&led_cdev->trigger_lock);
400#endif
401#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
402	led_cdev->brightness_hw_changed = -1;
403#endif
404	/* add to the list of leds */
405	down_write(&leds_list_lock);
406	list_add_tail(&led_cdev->node, &leds_list);
407	up_write(&leds_list_lock);
408
409	if (!led_cdev->max_brightness)
410		led_cdev->max_brightness = LED_FULL;
411
412	led_update_brightness(led_cdev);
413
414	led_init_core(led_cdev);
415
416#ifdef CONFIG_LEDS_TRIGGERS
417	led_trigger_set_default(led_cdev);
418#endif
419
420	mutex_unlock(&led_cdev->led_access);
421
422	dev_dbg(parent, "Registered led device: %s\n",
423			led_cdev->name);
424
425	return 0;
426}
427EXPORT_SYMBOL_GPL(led_classdev_register_ext);
428
429/**
430 * led_classdev_unregister - unregisters a object of led_properties class.
431 * @led_cdev: the led device to unregister
432 *
433 * Unregisters a previously registered via led_classdev_register object.
434 */
435void led_classdev_unregister(struct led_classdev *led_cdev)
436{
437	if (IS_ERR_OR_NULL(led_cdev->dev))
438		return;
439
440#ifdef CONFIG_LEDS_TRIGGERS
441	down_write(&led_cdev->trigger_lock);
442	if (led_cdev->trigger)
443		led_trigger_set(led_cdev, NULL);
444	up_write(&led_cdev->trigger_lock);
445#endif
446
447	led_cdev->flags |= LED_UNREGISTERING;
448
449	/* Stop blinking */
450	led_stop_software_blink(led_cdev);
451
452	led_set_brightness(led_cdev, LED_OFF);
453
454	flush_work(&led_cdev->set_brightness_work);
455
456	if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
457		led_remove_brightness_hw_changed(led_cdev);
458
459	device_unregister(led_cdev->dev);
460
461	down_write(&leds_list_lock);
462	list_del(&led_cdev->node);
463	up_write(&leds_list_lock);
464
465	mutex_destroy(&led_cdev->led_access);
466}
467EXPORT_SYMBOL_GPL(led_classdev_unregister);
468
469static void devm_led_classdev_release(struct device *dev, void *res)
470{
471	led_classdev_unregister(*(struct led_classdev **)res);
472}
473
474/**
475 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
476 *
477 * @parent: parent of LED device
478 * @led_cdev: the led_classdev structure for this device.
479 * @init_data: LED class device initialization data
480 */
481int devm_led_classdev_register_ext(struct device *parent,
482				   struct led_classdev *led_cdev,
483				   struct led_init_data *init_data)
484{
485	struct led_classdev **dr;
486	int rc;
487
488	dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
489	if (!dr)
490		return -ENOMEM;
491
492	rc = led_classdev_register_ext(parent, led_cdev, init_data);
493	if (rc) {
494		devres_free(dr);
495		return rc;
496	}
497
498	*dr = led_cdev;
499	devres_add(parent, dr);
500
501	return 0;
502}
503EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
504
505static int devm_led_classdev_match(struct device *dev, void *res, void *data)
506{
507	struct led_classdev **p = res;
508
509	if (WARN_ON(!p || !*p))
510		return 0;
511
512	return *p == data;
513}
514
515/**
516 * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
517 * @parent: The device to unregister.
518 * @led_cdev: the led_classdev structure for this device.
519 */
520void devm_led_classdev_unregister(struct device *dev,
521				  struct led_classdev *led_cdev)
522{
523	WARN_ON(devres_release(dev,
524			       devm_led_classdev_release,
525			       devm_led_classdev_match, led_cdev));
526}
527EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
528
529static int __init leds_init(void)
530{
531	leds_class = class_create(THIS_MODULE, "leds");
532	if (IS_ERR(leds_class))
533		return PTR_ERR(leds_class);
534	leds_class->pm = &leds_class_dev_pm_ops;
535	leds_class->dev_groups = led_groups;
536	return 0;
537}
538
539static void __exit leds_exit(void)
540{
541	class_destroy(leds_class);
542}
543
544subsys_initcall(leds_init);
545module_exit(leds_exit);
546
547MODULE_AUTHOR("John Lenz, Richard Purdie");
548MODULE_LICENSE("GPL");
549MODULE_DESCRIPTION("LED Class Interface");
550