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 
25 static struct class *leds_class;
26 
brightness_show(struct device * dev,struct device_attribute * attr,char * buf)27 static 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 
brightness_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)38 static 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;
62 unlock:
63 	mutex_unlock(&led_cdev->led_access);
64 	return ret;
65 }
66 static DEVICE_ATTR_RW(brightness);
67 
max_brightness_show(struct device * dev,struct device_attribute * attr,char * buf)68 static 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 }
75 static DEVICE_ATTR_RO(max_brightness);
76 
77 #ifdef CONFIG_LEDS_TRIGGERS
78 static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
79 static struct bin_attribute *led_trigger_bin_attrs[] = {
80 	&bin_attr_trigger,
81 	NULL,
82 };
83 static const struct attribute_group led_trigger_group = {
84 	.bin_attrs = led_trigger_bin_attrs,
85 };
86 #endif
87 
88 static struct attribute *led_class_attrs[] = {
89 	&dev_attr_brightness.attr,
90 	&dev_attr_max_brightness.attr,
91 	NULL,
92 };
93 
94 static const struct attribute_group led_group = {
95 	.attrs = led_class_attrs,
96 };
97 
98 static 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
brightness_hw_changed_show(struct device * dev,struct device_attribute * attr,char * buf)107 static 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 
118 static DEVICE_ATTR_RO(brightness_hw_changed);
119 
led_add_brightness_hw_changed(struct led_classdev * led_cdev)120 static 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 
led_remove_brightness_hw_changed(struct led_classdev * led_cdev)142 static 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 
led_classdev_notify_brightness_hw_changed(struct led_classdev * led_cdev,unsigned int brightness)148 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int brightness)
149 {
150 	if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
151 		return;
152 
153 	led_cdev->brightness_hw_changed = brightness;
154 	sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
155 }
156 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
157 #else
led_add_brightness_hw_changed(struct led_classdev * led_cdev)158 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
159 {
160 	return 0;
161 }
led_remove_brightness_hw_changed(struct led_classdev * led_cdev)162 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
163 {
164 }
165 #endif
166 
167 /**
168  * led_classdev_suspend - suspend an led_classdev.
169  * @led_cdev: the led_classdev to suspend.
170  */
led_classdev_suspend(struct led_classdev * led_cdev)171 void led_classdev_suspend(struct led_classdev *led_cdev)
172 {
173 	led_cdev->flags |= LED_SUSPENDED;
174 	led_set_brightness_nopm(led_cdev, 0);
175 	flush_work(&led_cdev->set_brightness_work);
176 }
177 EXPORT_SYMBOL_GPL(led_classdev_suspend);
178 
179 /**
180  * led_classdev_resume - resume an led_classdev.
181  * @led_cdev: the led_classdev to resume.
182  */
led_classdev_resume(struct led_classdev * led_cdev)183 void led_classdev_resume(struct led_classdev *led_cdev)
184 {
185 	led_set_brightness_nopm(led_cdev, led_cdev->brightness);
186 
187 	if (led_cdev->flash_resume)
188 		led_cdev->flash_resume(led_cdev);
189 
190 	led_cdev->flags &= ~LED_SUSPENDED;
191 }
192 EXPORT_SYMBOL_GPL(led_classdev_resume);
193 
194 #ifdef CONFIG_PM_SLEEP
led_suspend(struct device * dev)195 static int led_suspend(struct device *dev)
196 {
197 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
198 
199 	if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
200 		led_classdev_suspend(led_cdev);
201 
202 	return 0;
203 }
204 
led_resume(struct device * dev)205 static int led_resume(struct device *dev)
206 {
207 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
208 
209 	if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
210 		led_classdev_resume(led_cdev);
211 
212 	return 0;
213 }
214 #endif
215 
216 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
217 
218 /**
219  * of_led_get() - request a LED device via the LED framework
220  * @np: device node to get the LED device from
221  * @index: the index of the LED
222  *
223  * Returns the LED device parsed from the phandle specified in the "leds"
224  * property of a device tree node or a negative error-code on failure.
225  */
of_led_get(struct device_node * np,int index)226 struct led_classdev *of_led_get(struct device_node *np, int index)
227 {
228 	struct device *led_dev;
229 	struct led_classdev *led_cdev;
230 	struct device_node *led_node;
231 
232 	led_node = of_parse_phandle(np, "leds", index);
233 	if (!led_node)
234 		return ERR_PTR(-ENOENT);
235 
236 	led_dev = class_find_device_by_of_node(leds_class, led_node);
237 	of_node_put(led_node);
238 
239 	if (!led_dev)
240 		return ERR_PTR(-EPROBE_DEFER);
241 
242 	led_cdev = dev_get_drvdata(led_dev);
243 
244 	if (!try_module_get(led_cdev->dev->parent->driver->owner))
245 		return ERR_PTR(-ENODEV);
246 
247 	return led_cdev;
248 }
249 EXPORT_SYMBOL_GPL(of_led_get);
250 
251 /**
252  * led_put() - release a LED device
253  * @led_cdev: LED device
254  */
led_put(struct led_classdev * led_cdev)255 void led_put(struct led_classdev *led_cdev)
256 {
257 	module_put(led_cdev->dev->parent->driver->owner);
258 }
259 EXPORT_SYMBOL_GPL(led_put);
260 
devm_led_release(struct device * dev,void * res)261 static void devm_led_release(struct device *dev, void *res)
262 {
263 	struct led_classdev **p = res;
264 
265 	led_put(*p);
266 }
267 
268 /**
269  * devm_of_led_get - Resource-managed request of a LED device
270  * @dev:	LED consumer
271  * @index:	index of the LED to obtain in the consumer
272  *
273  * The device node of the device is parse to find the request LED device.
274  * The LED device returned from this function is automatically released
275  * on driver detach.
276  *
277  * @return a pointer to a LED device or ERR_PTR(errno) on failure.
278  */
devm_of_led_get(struct device * dev,int index)279 struct led_classdev *__must_check devm_of_led_get(struct device *dev,
280 						  int index)
281 {
282 	struct led_classdev *led;
283 	struct led_classdev **dr;
284 
285 	if (!dev)
286 		return ERR_PTR(-EINVAL);
287 
288 	led = of_led_get(dev->of_node, index);
289 	if (IS_ERR(led))
290 		return led;
291 
292 	dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
293 			  GFP_KERNEL);
294 	if (!dr) {
295 		led_put(led);
296 		return ERR_PTR(-ENOMEM);
297 	}
298 
299 	*dr = led;
300 	devres_add(dev, dr);
301 
302 	return led;
303 }
304 EXPORT_SYMBOL_GPL(devm_of_led_get);
305 
led_classdev_next_name(const char * init_name,char * name,size_t len)306 static int led_classdev_next_name(const char *init_name, char *name,
307 				  size_t len)
308 {
309 	unsigned int i = 0;
310 	int ret = 0;
311 	struct device *dev;
312 
313 	strlcpy(name, init_name, len);
314 
315 	while ((ret < len) &&
316 	       (dev = class_find_device_by_name(leds_class, name))) {
317 		put_device(dev);
318 		ret = snprintf(name, len, "%s_%u", init_name, ++i);
319 	}
320 
321 	if (ret >= len)
322 		return -ENOMEM;
323 
324 	return i;
325 }
326 
327 /**
328  * led_classdev_register_ext - register a new object of led_classdev class
329  *			       with init data.
330  *
331  * @parent: parent of LED device
332  * @led_cdev: the led_classdev structure for this device.
333  * @init_data: LED class device initialization data
334  */
led_classdev_register_ext(struct device * parent,struct led_classdev * led_cdev,struct led_init_data * init_data)335 int led_classdev_register_ext(struct device *parent,
336 			      struct led_classdev *led_cdev,
337 			      struct led_init_data *init_data)
338 {
339 	char composed_name[LED_MAX_NAME_SIZE];
340 	char final_name[LED_MAX_NAME_SIZE];
341 	const char *proposed_name = composed_name;
342 	int ret;
343 
344 	if (init_data) {
345 		if (init_data->devname_mandatory && !init_data->devicename) {
346 			dev_err(parent, "Mandatory device name is missing");
347 			return -EINVAL;
348 		}
349 		ret = led_compose_name(parent, init_data, composed_name);
350 		if (ret < 0)
351 			return ret;
352 
353 		if (init_data->fwnode) {
354 			fwnode_property_read_string(init_data->fwnode,
355 				"linux,default-trigger",
356 				&led_cdev->default_trigger);
357 
358 			if (fwnode_property_present(init_data->fwnode,
359 						    "retain-state-shutdown"))
360 				led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
361 		}
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 		device_set_node(led_cdev->dev, init_data->fwnode);
380 
381 	if (ret)
382 		dev_warn(parent, "Led %s renamed to %s due to name collision",
383 				proposed_name, dev_name(led_cdev->dev));
384 
385 	if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
386 		ret = led_add_brightness_hw_changed(led_cdev);
387 		if (ret) {
388 			device_unregister(led_cdev->dev);
389 			led_cdev->dev = NULL;
390 			mutex_unlock(&led_cdev->led_access);
391 			return ret;
392 		}
393 	}
394 
395 	led_cdev->work_flags = 0;
396 #ifdef CONFIG_LEDS_TRIGGERS
397 	init_rwsem(&led_cdev->trigger_lock);
398 #endif
399 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
400 	led_cdev->brightness_hw_changed = -1;
401 #endif
402 	/* add to the list of leds */
403 	down_write(&leds_list_lock);
404 	list_add_tail(&led_cdev->node, &leds_list);
405 	up_write(&leds_list_lock);
406 
407 	if (!led_cdev->max_brightness)
408 		led_cdev->max_brightness = LED_FULL;
409 
410 	led_update_brightness(led_cdev);
411 
412 	led_init_core(led_cdev);
413 
414 #ifdef CONFIG_LEDS_TRIGGERS
415 	led_trigger_set_default(led_cdev);
416 #endif
417 
418 	mutex_unlock(&led_cdev->led_access);
419 
420 	dev_dbg(parent, "Registered led device: %s\n",
421 			led_cdev->name);
422 
423 	return 0;
424 }
425 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
426 
427 /**
428  * led_classdev_unregister - unregisters a object of led_properties class.
429  * @led_cdev: the led device to unregister
430  *
431  * Unregisters a previously registered via led_classdev_register object.
432  */
led_classdev_unregister(struct led_classdev * led_cdev)433 void led_classdev_unregister(struct led_classdev *led_cdev)
434 {
435 	if (IS_ERR_OR_NULL(led_cdev->dev))
436 		return;
437 
438 #ifdef CONFIG_LEDS_TRIGGERS
439 	down_write(&led_cdev->trigger_lock);
440 	if (led_cdev->trigger)
441 		led_trigger_set(led_cdev, NULL);
442 	up_write(&led_cdev->trigger_lock);
443 #endif
444 
445 	led_cdev->flags |= LED_UNREGISTERING;
446 
447 	/* Stop blinking */
448 	led_stop_software_blink(led_cdev);
449 
450 	if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
451 		led_set_brightness(led_cdev, LED_OFF);
452 
453 	flush_work(&led_cdev->set_brightness_work);
454 
455 	if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
456 		led_remove_brightness_hw_changed(led_cdev);
457 
458 	device_unregister(led_cdev->dev);
459 
460 	down_write(&leds_list_lock);
461 	list_del(&led_cdev->node);
462 	up_write(&leds_list_lock);
463 
464 	mutex_destroy(&led_cdev->led_access);
465 }
466 EXPORT_SYMBOL_GPL(led_classdev_unregister);
467 
devm_led_classdev_release(struct device * dev,void * res)468 static void devm_led_classdev_release(struct device *dev, void *res)
469 {
470 	led_classdev_unregister(*(struct led_classdev **)res);
471 }
472 
473 /**
474  * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
475  *
476  * @parent: parent of LED device
477  * @led_cdev: the led_classdev structure for this device.
478  * @init_data: LED class device initialization data
479  */
devm_led_classdev_register_ext(struct device * parent,struct led_classdev * led_cdev,struct led_init_data * init_data)480 int devm_led_classdev_register_ext(struct device *parent,
481 				   struct led_classdev *led_cdev,
482 				   struct led_init_data *init_data)
483 {
484 	struct led_classdev **dr;
485 	int rc;
486 
487 	dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
488 	if (!dr)
489 		return -ENOMEM;
490 
491 	rc = led_classdev_register_ext(parent, led_cdev, init_data);
492 	if (rc) {
493 		devres_free(dr);
494 		return rc;
495 	}
496 
497 	*dr = led_cdev;
498 	devres_add(parent, dr);
499 
500 	return 0;
501 }
502 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
503 
devm_led_classdev_match(struct device * dev,void * res,void * data)504 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
505 {
506 	struct led_classdev **p = res;
507 
508 	if (WARN_ON(!p || !*p))
509 		return 0;
510 
511 	return *p == data;
512 }
513 
514 /**
515  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
516  * @dev: The device to unregister.
517  * @led_cdev: the led_classdev structure for this device.
518  */
devm_led_classdev_unregister(struct device * dev,struct led_classdev * led_cdev)519 void devm_led_classdev_unregister(struct device *dev,
520 				  struct led_classdev *led_cdev)
521 {
522 	WARN_ON(devres_release(dev,
523 			       devm_led_classdev_release,
524 			       devm_led_classdev_match, led_cdev));
525 }
526 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
527 
leds_init(void)528 static int __init leds_init(void)
529 {
530 	leds_class = class_create(THIS_MODULE, "leds");
531 	if (IS_ERR(leds_class))
532 		return PTR_ERR(leds_class);
533 	leds_class->pm = &leds_class_dev_pm_ops;
534 	leds_class->dev_groups = led_groups;
535 	return 0;
536 }
537 
leds_exit(void)538 static void __exit leds_exit(void)
539 {
540 	class_destroy(leds_class);
541 }
542 
543 subsys_initcall(leds_init);
544 module_exit(leds_exit);
545 
546 MODULE_AUTHOR("John Lenz, Richard Purdie");
547 MODULE_LICENSE("GPL");
548 MODULE_DESCRIPTION("LED Class Interface");
549