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 "leds.h"
23
24 static struct class *leds_class;
25
brightness_show(struct device * dev,struct device_attribute * attr,char * buf)26 static ssize_t brightness_show(struct device *dev,
27 struct device_attribute *attr, char *buf)
28 {
29 struct led_classdev *led_cdev = dev_get_drvdata(dev);
30
31 /* no lock needed for this */
32 led_update_brightness(led_cdev);
33
34 return sprintf(buf, "%u\n", led_cdev->brightness);
35 }
36
brightness_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)37 static ssize_t brightness_store(struct device *dev,
38 struct device_attribute *attr, const char *buf, size_t size)
39 {
40 struct led_classdev *led_cdev = dev_get_drvdata(dev);
41 unsigned long state;
42 ssize_t ret;
43
44 mutex_lock(&led_cdev->led_access);
45
46 if (led_sysfs_is_disabled(led_cdev)) {
47 ret = -EBUSY;
48 goto unlock;
49 }
50
51 ret = kstrtoul(buf, 10, &state);
52 if (ret)
53 goto unlock;
54
55 if (state == LED_OFF)
56 led_trigger_remove(led_cdev);
57 led_set_brightness(led_cdev, state);
58 flush_work(&led_cdev->set_brightness_work);
59
60 ret = size;
61 unlock:
62 mutex_unlock(&led_cdev->led_access);
63 return ret;
64 }
65 static DEVICE_ATTR_RW(brightness);
66
max_brightness_show(struct device * dev,struct device_attribute * attr,char * buf)67 static ssize_t max_brightness_show(struct device *dev,
68 struct device_attribute *attr, char *buf)
69 {
70 struct led_classdev *led_cdev = dev_get_drvdata(dev);
71
72 return sprintf(buf, "%u\n", led_cdev->max_brightness);
73 }
74 static DEVICE_ATTR_RO(max_brightness);
75
76 #ifdef CONFIG_LEDS_TRIGGERS
77 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
78 static struct attribute *led_trigger_attrs[] = {
79 &dev_attr_trigger.attr,
80 NULL,
81 };
82 static const struct attribute_group led_trigger_group = {
83 .attrs = led_trigger_attrs,
84 };
85 #endif
86
87 static struct attribute *led_class_attrs[] = {
88 &dev_attr_brightness.attr,
89 &dev_attr_max_brightness.attr,
90 NULL,
91 };
92
93 static const struct attribute_group led_group = {
94 .attrs = led_class_attrs,
95 };
96
97 static const struct attribute_group *led_groups[] = {
98 &led_group,
99 #ifdef CONFIG_LEDS_TRIGGERS
100 &led_trigger_group,
101 #endif
102 NULL,
103 };
104
105 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
brightness_hw_changed_show(struct device * dev,struct device_attribute * attr,char * buf)106 static ssize_t brightness_hw_changed_show(struct device *dev,
107 struct device_attribute *attr, char *buf)
108 {
109 struct led_classdev *led_cdev = dev_get_drvdata(dev);
110
111 if (led_cdev->brightness_hw_changed == -1)
112 return -ENODATA;
113
114 return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
115 }
116
117 static DEVICE_ATTR_RO(brightness_hw_changed);
118
led_add_brightness_hw_changed(struct led_classdev * led_cdev)119 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
120 {
121 struct device *dev = led_cdev->dev;
122 int ret;
123
124 ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
125 if (ret) {
126 dev_err(dev, "Error creating brightness_hw_changed\n");
127 return ret;
128 }
129
130 led_cdev->brightness_hw_changed_kn =
131 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
132 if (!led_cdev->brightness_hw_changed_kn) {
133 dev_err(dev, "Error getting brightness_hw_changed kn\n");
134 device_remove_file(dev, &dev_attr_brightness_hw_changed);
135 return -ENXIO;
136 }
137
138 return 0;
139 }
140
led_remove_brightness_hw_changed(struct led_classdev * led_cdev)141 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
142 {
143 sysfs_put(led_cdev->brightness_hw_changed_kn);
144 device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
145 }
146
led_classdev_notify_brightness_hw_changed(struct led_classdev * led_cdev,enum led_brightness brightness)147 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev,
148 enum led_brightness 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
led_classdev_next_name(const char * init_name,char * name,size_t len)218 static int led_classdev_next_name(const char *init_name, char *name,
219 size_t len)
220 {
221 unsigned int i = 0;
222 int ret = 0;
223 struct device *dev;
224
225 strlcpy(name, init_name, len);
226
227 while ((ret < len) &&
228 (dev = class_find_device_by_name(leds_class, name))) {
229 put_device(dev);
230 ret = snprintf(name, len, "%s_%u", init_name, ++i);
231 }
232
233 if (ret >= len)
234 return -ENOMEM;
235
236 return i;
237 }
238
239 /**
240 * led_classdev_register_ext - register a new object of led_classdev class
241 * with init data.
242 *
243 * @parent: parent of LED device
244 * @led_cdev: the led_classdev structure for this device.
245 * @init_data: LED class device initialization data
246 */
led_classdev_register_ext(struct device * parent,struct led_classdev * led_cdev,struct led_init_data * init_data)247 int led_classdev_register_ext(struct device *parent,
248 struct led_classdev *led_cdev,
249 struct led_init_data *init_data)
250 {
251 char composed_name[LED_MAX_NAME_SIZE];
252 char final_name[LED_MAX_NAME_SIZE];
253 const char *proposed_name = composed_name;
254 int ret;
255
256 if (init_data) {
257 if (init_data->devname_mandatory && !init_data->devicename) {
258 dev_err(parent, "Mandatory device name is missing");
259 return -EINVAL;
260 }
261 ret = led_compose_name(parent, init_data, composed_name);
262 if (ret < 0)
263 return ret;
264 } else {
265 proposed_name = led_cdev->name;
266 }
267
268 ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
269 if (ret < 0)
270 return ret;
271
272 mutex_init(&led_cdev->led_access);
273 mutex_lock(&led_cdev->led_access);
274 led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
275 led_cdev, led_cdev->groups, "%s", final_name);
276 if (IS_ERR(led_cdev->dev)) {
277 mutex_unlock(&led_cdev->led_access);
278 return PTR_ERR(led_cdev->dev);
279 }
280 if (init_data && init_data->fwnode)
281 led_cdev->dev->fwnode = init_data->fwnode;
282
283 if (ret)
284 dev_warn(parent, "Led %s renamed to %s due to name collision",
285 proposed_name, dev_name(led_cdev->dev));
286
287 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
288 ret = led_add_brightness_hw_changed(led_cdev);
289 if (ret) {
290 device_unregister(led_cdev->dev);
291 led_cdev->dev = NULL;
292 mutex_unlock(&led_cdev->led_access);
293 return ret;
294 }
295 }
296
297 led_cdev->work_flags = 0;
298 #ifdef CONFIG_LEDS_TRIGGERS
299 init_rwsem(&led_cdev->trigger_lock);
300 #endif
301 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
302 led_cdev->brightness_hw_changed = -1;
303 #endif
304 /* add to the list of leds */
305 down_write(&leds_list_lock);
306 list_add_tail(&led_cdev->node, &leds_list);
307 up_write(&leds_list_lock);
308
309 if (!led_cdev->max_brightness)
310 led_cdev->max_brightness = LED_FULL;
311
312 led_update_brightness(led_cdev);
313
314 led_init_core(led_cdev);
315
316 #ifdef CONFIG_LEDS_TRIGGERS
317 led_trigger_set_default(led_cdev);
318 #endif
319
320 mutex_unlock(&led_cdev->led_access);
321
322 dev_dbg(parent, "Registered led device: %s\n",
323 led_cdev->name);
324
325 return 0;
326 }
327 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
328
329 /**
330 * led_classdev_unregister - unregisters a object of led_properties class.
331 * @led_cdev: the led device to unregister
332 *
333 * Unregisters a previously registered via led_classdev_register object.
334 */
led_classdev_unregister(struct led_classdev * led_cdev)335 void led_classdev_unregister(struct led_classdev *led_cdev)
336 {
337 if (IS_ERR_OR_NULL(led_cdev->dev))
338 return;
339
340 #ifdef CONFIG_LEDS_TRIGGERS
341 down_write(&led_cdev->trigger_lock);
342 if (led_cdev->trigger)
343 led_trigger_set(led_cdev, NULL);
344 up_write(&led_cdev->trigger_lock);
345 #endif
346
347 led_cdev->flags |= LED_UNREGISTERING;
348
349 /* Stop blinking */
350 led_stop_software_blink(led_cdev);
351
352 led_set_brightness(led_cdev, LED_OFF);
353
354 flush_work(&led_cdev->set_brightness_work);
355
356 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
357 led_remove_brightness_hw_changed(led_cdev);
358
359 device_unregister(led_cdev->dev);
360
361 down_write(&leds_list_lock);
362 list_del(&led_cdev->node);
363 up_write(&leds_list_lock);
364
365 mutex_destroy(&led_cdev->led_access);
366 }
367 EXPORT_SYMBOL_GPL(led_classdev_unregister);
368
devm_led_classdev_release(struct device * dev,void * res)369 static void devm_led_classdev_release(struct device *dev, void *res)
370 {
371 led_classdev_unregister(*(struct led_classdev **)res);
372 }
373
374 /**
375 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
376 *
377 * @parent: parent of LED device
378 * @led_cdev: the led_classdev structure for this device.
379 * @init_data: LED class device initialization data
380 */
devm_led_classdev_register_ext(struct device * parent,struct led_classdev * led_cdev,struct led_init_data * init_data)381 int devm_led_classdev_register_ext(struct device *parent,
382 struct led_classdev *led_cdev,
383 struct led_init_data *init_data)
384 {
385 struct led_classdev **dr;
386 int rc;
387
388 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
389 if (!dr)
390 return -ENOMEM;
391
392 rc = led_classdev_register_ext(parent, led_cdev, init_data);
393 if (rc) {
394 devres_free(dr);
395 return rc;
396 }
397
398 *dr = led_cdev;
399 devres_add(parent, dr);
400
401 return 0;
402 }
403 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
404
devm_led_classdev_match(struct device * dev,void * res,void * data)405 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
406 {
407 struct led_cdev **p = res;
408
409 if (WARN_ON(!p || !*p))
410 return 0;
411
412 return *p == data;
413 }
414
415 /**
416 * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
417 * @parent: The device to unregister.
418 * @led_cdev: the led_classdev structure for this device.
419 */
devm_led_classdev_unregister(struct device * dev,struct led_classdev * led_cdev)420 void devm_led_classdev_unregister(struct device *dev,
421 struct led_classdev *led_cdev)
422 {
423 WARN_ON(devres_release(dev,
424 devm_led_classdev_release,
425 devm_led_classdev_match, led_cdev));
426 }
427 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
428
leds_init(void)429 static int __init leds_init(void)
430 {
431 leds_class = class_create(THIS_MODULE, "leds");
432 if (IS_ERR(leds_class))
433 return PTR_ERR(leds_class);
434 leds_class->pm = &leds_class_dev_pm_ops;
435 leds_class->dev_groups = led_groups;
436 return 0;
437 }
438
leds_exit(void)439 static void __exit leds_exit(void)
440 {
441 class_destroy(leds_class);
442 }
443
444 subsys_initcall(leds_init);
445 module_exit(leds_exit);
446
447 MODULE_AUTHOR("John Lenz, Richard Purdie");
448 MODULE_LICENSE("GPL");
449 MODULE_DESCRIPTION("LED Class Interface");
450