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,enum led_brightness brightness)148 void 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 }
157 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
158 #else
led_add_brightness_hw_changed(struct led_classdev * led_cdev)159 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
160 {
161 return 0;
162 }
led_remove_brightness_hw_changed(struct led_classdev * led_cdev)163 static 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 */
led_classdev_suspend(struct led_classdev * led_cdev)172 void 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 }
178 EXPORT_SYMBOL_GPL(led_classdev_suspend);
179
180 /**
181 * led_classdev_resume - resume an led_classdev.
182 * @led_cdev: the led_classdev to resume.
183 */
led_classdev_resume(struct led_classdev * led_cdev)184 void 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 }
193 EXPORT_SYMBOL_GPL(led_classdev_resume);
194
195 #ifdef CONFIG_PM_SLEEP
led_suspend(struct device * dev)196 static 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
led_resume(struct device * dev)206 static 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
217 static 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 */
of_led_get(struct device_node * np,int index)227 struct 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
240 if (!led_dev)
241 return ERR_PTR(-EPROBE_DEFER);
242
243 led_cdev = dev_get_drvdata(led_dev);
244
245 if (!try_module_get(led_cdev->dev->parent->driver->owner))
246 return ERR_PTR(-ENODEV);
247
248 return led_cdev;
249 }
250 EXPORT_SYMBOL_GPL(of_led_get);
251
252 /**
253 * led_put() - release a LED device
254 * @led_cdev: LED device
255 */
led_put(struct led_classdev * led_cdev)256 void led_put(struct led_classdev *led_cdev)
257 {
258 module_put(led_cdev->dev->parent->driver->owner);
259 }
260 EXPORT_SYMBOL_GPL(led_put);
261
devm_led_release(struct device * dev,void * res)262 static void devm_led_release(struct device *dev, void *res)
263 {
264 struct led_classdev **p = res;
265
266 led_put(*p);
267 }
268
269 /**
270 * devm_of_led_get - Resource-managed request of a LED device
271 * @dev: LED consumer
272 * @index: index of the LED to obtain in the consumer
273 *
274 * The device node of the device is parse to find the request LED device.
275 * The LED device returned from this function is automatically released
276 * on driver detach.
277 *
278 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
279 */
devm_of_led_get(struct device * dev,int index)280 struct led_classdev *__must_check devm_of_led_get(struct device *dev,
281 int index)
282 {
283 struct led_classdev *led;
284 struct led_classdev **dr;
285
286 if (!dev)
287 return ERR_PTR(-EINVAL);
288
289 led = of_led_get(dev->of_node, index);
290 if (IS_ERR(led))
291 return led;
292
293 dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
294 GFP_KERNEL);
295 if (!dr) {
296 led_put(led);
297 return ERR_PTR(-ENOMEM);
298 }
299
300 *dr = led;
301 devres_add(dev, dr);
302
303 return led;
304 }
305 EXPORT_SYMBOL_GPL(devm_of_led_get);
306
led_classdev_next_name(const char * init_name,char * name,size_t len)307 static int led_classdev_next_name(const char *init_name, char *name,
308 size_t len)
309 {
310 unsigned int i = 0;
311 int ret = 0;
312 struct device *dev;
313
314 strlcpy(name, init_name, len);
315
316 while ((ret < len) &&
317 (dev = class_find_device_by_name(leds_class, name))) {
318 put_device(dev);
319 ret = snprintf(name, len, "%s_%u", init_name, ++i);
320 }
321
322 if (ret >= len)
323 return -ENOMEM;
324
325 return i;
326 }
327
328 /**
329 * led_classdev_register_ext - register a new object of led_classdev class
330 * with init data.
331 *
332 * @parent: parent of LED device
333 * @led_cdev: the led_classdev structure for this device.
334 * @init_data: LED class device initialization data
335 */
led_classdev_register_ext(struct device * parent,struct led_classdev * led_cdev,struct led_init_data * init_data)336 int led_classdev_register_ext(struct device *parent,
337 struct led_classdev *led_cdev,
338 struct led_init_data *init_data)
339 {
340 char composed_name[LED_MAX_NAME_SIZE];
341 char final_name[LED_MAX_NAME_SIZE];
342 const char *proposed_name = composed_name;
343 int ret;
344
345 if (init_data) {
346 if (init_data->devname_mandatory && !init_data->devicename) {
347 dev_err(parent, "Mandatory device name is missing");
348 return -EINVAL;
349 }
350 ret = led_compose_name(parent, init_data, composed_name);
351 if (ret < 0)
352 return ret;
353
354 if (init_data->fwnode)
355 fwnode_property_read_string(init_data->fwnode,
356 "linux,default-trigger",
357 &led_cdev->default_trigger);
358 } else {
359 proposed_name = led_cdev->name;
360 }
361
362 ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
363 if (ret < 0)
364 return ret;
365
366 mutex_init(&led_cdev->led_access);
367 mutex_lock(&led_cdev->led_access);
368 led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
369 led_cdev, led_cdev->groups, "%s", final_name);
370 if (IS_ERR(led_cdev->dev)) {
371 mutex_unlock(&led_cdev->led_access);
372 return PTR_ERR(led_cdev->dev);
373 }
374 if (init_data && init_data->fwnode) {
375 led_cdev->dev->fwnode = init_data->fwnode;
376 led_cdev->dev->of_node = to_of_node(init_data->fwnode);
377 }
378
379 if (ret)
380 dev_warn(parent, "Led %s renamed to %s due to name collision",
381 proposed_name, dev_name(led_cdev->dev));
382
383 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
384 ret = led_add_brightness_hw_changed(led_cdev);
385 if (ret) {
386 device_unregister(led_cdev->dev);
387 led_cdev->dev = NULL;
388 mutex_unlock(&led_cdev->led_access);
389 return ret;
390 }
391 }
392
393 led_cdev->work_flags = 0;
394 #ifdef CONFIG_LEDS_TRIGGERS
395 init_rwsem(&led_cdev->trigger_lock);
396 #endif
397 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
398 led_cdev->brightness_hw_changed = -1;
399 #endif
400 /* add to the list of leds */
401 down_write(&leds_list_lock);
402 list_add_tail(&led_cdev->node, &leds_list);
403 up_write(&leds_list_lock);
404
405 if (!led_cdev->max_brightness)
406 led_cdev->max_brightness = LED_FULL;
407
408 led_update_brightness(led_cdev);
409
410 led_init_core(led_cdev);
411
412 #ifdef CONFIG_LEDS_TRIGGERS
413 led_trigger_set_default(led_cdev);
414 #endif
415
416 mutex_unlock(&led_cdev->led_access);
417
418 dev_dbg(parent, "Registered led device: %s\n",
419 led_cdev->name);
420
421 return 0;
422 }
423 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
424
425 /**
426 * led_classdev_unregister - unregisters a object of led_properties class.
427 * @led_cdev: the led device to unregister
428 *
429 * Unregisters a previously registered via led_classdev_register object.
430 */
led_classdev_unregister(struct led_classdev * led_cdev)431 void led_classdev_unregister(struct led_classdev *led_cdev)
432 {
433 if (IS_ERR_OR_NULL(led_cdev->dev))
434 return;
435
436 #ifdef CONFIG_LEDS_TRIGGERS
437 down_write(&led_cdev->trigger_lock);
438 if (led_cdev->trigger)
439 led_trigger_set(led_cdev, NULL);
440 up_write(&led_cdev->trigger_lock);
441 #endif
442
443 led_cdev->flags |= LED_UNREGISTERING;
444
445 /* Stop blinking */
446 led_stop_software_blink(led_cdev);
447
448 led_set_brightness(led_cdev, LED_OFF);
449
450 flush_work(&led_cdev->set_brightness_work);
451
452 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
453 led_remove_brightness_hw_changed(led_cdev);
454
455 device_unregister(led_cdev->dev);
456
457 down_write(&leds_list_lock);
458 list_del(&led_cdev->node);
459 up_write(&leds_list_lock);
460
461 mutex_destroy(&led_cdev->led_access);
462 }
463 EXPORT_SYMBOL_GPL(led_classdev_unregister);
464
devm_led_classdev_release(struct device * dev,void * res)465 static void devm_led_classdev_release(struct device *dev, void *res)
466 {
467 led_classdev_unregister(*(struct led_classdev **)res);
468 }
469
470 /**
471 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
472 *
473 * @parent: parent of LED device
474 * @led_cdev: the led_classdev structure for this device.
475 * @init_data: LED class device initialization data
476 */
devm_led_classdev_register_ext(struct device * parent,struct led_classdev * led_cdev,struct led_init_data * init_data)477 int devm_led_classdev_register_ext(struct device *parent,
478 struct led_classdev *led_cdev,
479 struct led_init_data *init_data)
480 {
481 struct led_classdev **dr;
482 int rc;
483
484 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
485 if (!dr)
486 return -ENOMEM;
487
488 rc = led_classdev_register_ext(parent, led_cdev, init_data);
489 if (rc) {
490 devres_free(dr);
491 return rc;
492 }
493
494 *dr = led_cdev;
495 devres_add(parent, dr);
496
497 return 0;
498 }
499 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
500
devm_led_classdev_match(struct device * dev,void * res,void * data)501 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
502 {
503 struct led_classdev **p = res;
504
505 if (WARN_ON(!p || !*p))
506 return 0;
507
508 return *p == data;
509 }
510
511 /**
512 * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
513 * @parent: The device to unregister.
514 * @led_cdev: the led_classdev structure for this device.
515 */
devm_led_classdev_unregister(struct device * dev,struct led_classdev * led_cdev)516 void devm_led_classdev_unregister(struct device *dev,
517 struct led_classdev *led_cdev)
518 {
519 WARN_ON(devres_release(dev,
520 devm_led_classdev_release,
521 devm_led_classdev_match, led_cdev));
522 }
523 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
524
leds_init(void)525 static int __init leds_init(void)
526 {
527 leds_class = class_create(THIS_MODULE, "leds");
528 if (IS_ERR(leds_class))
529 return PTR_ERR(leds_class);
530 leds_class->pm = &leds_class_dev_pm_ops;
531 leds_class->dev_groups = led_groups;
532 return 0;
533 }
534
leds_exit(void)535 static void __exit leds_exit(void)
536 {
537 class_destroy(leds_class);
538 }
539
540 subsys_initcall(leds_init);
541 module_exit(leds_exit);
542
543 MODULE_AUTHOR("John Lenz, Richard Purdie");
544 MODULE_LICENSE("GPL");
545 MODULE_DESCRIPTION("LED Class Interface");
546