led-triggers.c 11 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * LED Triggers Core
  4. *
  5. * Copyright 2005-2007 Openedhand Ltd.
  6. *
  7. * Author: Richard Purdie <rpurdie@openedhand.com>
  8. */
  9. #include <linux/export.h>
  10. #include <linux/kernel.h>
  11. #include <linux/list.h>
  12. #include <linux/spinlock.h>
  13. #include <linux/device.h>
  14. #include <linux/timer.h>
  15. #include <linux/rwsem.h>
  16. #include <linux/leds.h>
  17. #include <linux/slab.h>
  18. #include <linux/mm.h>
  19. #include "leds.h"
  20. /*
  21. * Nests outside led_cdev->trigger_lock
  22. */
  23. static DECLARE_RWSEM(triggers_list_lock);
  24. LIST_HEAD(trigger_list);
  25. /* Used by LED Class */
  26. static inline bool
  27. trigger_relevant(struct led_classdev *led_cdev, struct led_trigger *trig)
  28. {
  29. return !trig->trigger_type || trig->trigger_type == led_cdev->trigger_type;
  30. }
  31. ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
  32. struct bin_attribute *bin_attr, char *buf,
  33. loff_t pos, size_t count)
  34. {
  35. struct device *dev = kobj_to_dev(kobj);
  36. struct led_classdev *led_cdev = dev_get_drvdata(dev);
  37. struct led_trigger *trig;
  38. int ret = count;
  39. mutex_lock(&led_cdev->led_access);
  40. if (led_sysfs_is_disabled(led_cdev)) {
  41. ret = -EBUSY;
  42. goto unlock;
  43. }
  44. if (sysfs_streq(buf, "none")) {
  45. led_trigger_remove(led_cdev);
  46. goto unlock;
  47. }
  48. down_read(&triggers_list_lock);
  49. list_for_each_entry(trig, &trigger_list, next_trig) {
  50. if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {
  51. down_write(&led_cdev->trigger_lock);
  52. led_trigger_set(led_cdev, trig);
  53. up_write(&led_cdev->trigger_lock);
  54. up_read(&triggers_list_lock);
  55. goto unlock;
  56. }
  57. }
  58. /* we come here only if buf matches no trigger */
  59. ret = -EINVAL;
  60. up_read(&triggers_list_lock);
  61. unlock:
  62. mutex_unlock(&led_cdev->led_access);
  63. return ret;
  64. }
  65. EXPORT_SYMBOL_GPL(led_trigger_write);
  66. __printf(3, 4)
  67. static int led_trigger_snprintf(char *buf, ssize_t size, const char *fmt, ...)
  68. {
  69. va_list args;
  70. int i;
  71. va_start(args, fmt);
  72. if (size <= 0)
  73. i = vsnprintf(NULL, 0, fmt, args);
  74. else
  75. i = vscnprintf(buf, size, fmt, args);
  76. va_end(args);
  77. return i;
  78. }
  79. static int led_trigger_format(char *buf, size_t size,
  80. struct led_classdev *led_cdev)
  81. {
  82. struct led_trigger *trig;
  83. int len = led_trigger_snprintf(buf, size, "%s",
  84. led_cdev->trigger ? "none" : "[none]");
  85. list_for_each_entry(trig, &trigger_list, next_trig) {
  86. bool hit;
  87. if (!trigger_relevant(led_cdev, trig))
  88. continue;
  89. hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name);
  90. len += led_trigger_snprintf(buf + len, size - len,
  91. " %s%s%s", hit ? "[" : "",
  92. trig->name, hit ? "]" : "");
  93. }
  94. len += led_trigger_snprintf(buf + len, size - len, "\n");
  95. return len;
  96. }
  97. /*
  98. * It was stupid to create 10000 cpu triggers, but we are stuck with it now.
  99. * Don't make that mistake again. We work around it here by creating binary
  100. * attribute, which is not limited by length. This is _not_ good design, do not
  101. * copy it.
  102. */
  103. ssize_t led_trigger_read(struct file *filp, struct kobject *kobj,
  104. struct bin_attribute *attr, char *buf,
  105. loff_t pos, size_t count)
  106. {
  107. struct device *dev = kobj_to_dev(kobj);
  108. struct led_classdev *led_cdev = dev_get_drvdata(dev);
  109. void *data;
  110. int len;
  111. down_read(&triggers_list_lock);
  112. down_read(&led_cdev->trigger_lock);
  113. len = led_trigger_format(NULL, 0, led_cdev);
  114. data = kvmalloc(len + 1, GFP_KERNEL);
  115. if (!data) {
  116. up_read(&led_cdev->trigger_lock);
  117. up_read(&triggers_list_lock);
  118. return -ENOMEM;
  119. }
  120. len = led_trigger_format(data, len + 1, led_cdev);
  121. up_read(&led_cdev->trigger_lock);
  122. up_read(&triggers_list_lock);
  123. len = memory_read_from_buffer(buf, count, &pos, data, len);
  124. kvfree(data);
  125. return len;
  126. }
  127. EXPORT_SYMBOL_GPL(led_trigger_read);
  128. /* Caller must ensure led_cdev->trigger_lock held */
  129. int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
  130. {
  131. unsigned long flags;
  132. char *event = NULL;
  133. char *envp[2];
  134. const char *name;
  135. int ret;
  136. if (!led_cdev->trigger && !trig)
  137. return 0;
  138. name = trig ? trig->name : "none";
  139. event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
  140. /* Remove any existing trigger */
  141. if (led_cdev->trigger) {
  142. write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
  143. list_del(&led_cdev->trig_list);
  144. write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
  145. flags);
  146. cancel_work_sync(&led_cdev->set_brightness_work);
  147. led_stop_software_blink(led_cdev);
  148. if (led_cdev->trigger->deactivate)
  149. led_cdev->trigger->deactivate(led_cdev);
  150. device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
  151. led_cdev->trigger = NULL;
  152. led_cdev->trigger_data = NULL;
  153. led_cdev->activated = false;
  154. led_set_brightness(led_cdev, LED_OFF);
  155. }
  156. if (trig) {
  157. write_lock_irqsave(&trig->leddev_list_lock, flags);
  158. list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
  159. write_unlock_irqrestore(&trig->leddev_list_lock, flags);
  160. led_cdev->trigger = trig;
  161. if (trig->activate)
  162. ret = trig->activate(led_cdev);
  163. else
  164. ret = 0;
  165. if (ret)
  166. goto err_activate;
  167. ret = device_add_groups(led_cdev->dev, trig->groups);
  168. if (ret) {
  169. dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
  170. goto err_add_groups;
  171. }
  172. }
  173. if (event) {
  174. envp[0] = event;
  175. envp[1] = NULL;
  176. if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
  177. dev_err(led_cdev->dev,
  178. "%s: Error sending uevent\n", __func__);
  179. kfree(event);
  180. }
  181. return 0;
  182. err_add_groups:
  183. if (trig->deactivate)
  184. trig->deactivate(led_cdev);
  185. err_activate:
  186. write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
  187. list_del(&led_cdev->trig_list);
  188. write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
  189. led_cdev->trigger = NULL;
  190. led_cdev->trigger_data = NULL;
  191. led_set_brightness(led_cdev, LED_OFF);
  192. kfree(event);
  193. return ret;
  194. }
  195. EXPORT_SYMBOL_GPL(led_trigger_set);
  196. void led_trigger_remove(struct led_classdev *led_cdev)
  197. {
  198. down_write(&led_cdev->trigger_lock);
  199. led_trigger_set(led_cdev, NULL);
  200. up_write(&led_cdev->trigger_lock);
  201. }
  202. EXPORT_SYMBOL_GPL(led_trigger_remove);
  203. void led_trigger_set_default(struct led_classdev *led_cdev)
  204. {
  205. struct led_trigger *trig;
  206. if (!led_cdev->default_trigger)
  207. return;
  208. down_read(&triggers_list_lock);
  209. down_write(&led_cdev->trigger_lock);
  210. list_for_each_entry(trig, &trigger_list, next_trig) {
  211. if (!strcmp(led_cdev->default_trigger, trig->name) &&
  212. trigger_relevant(led_cdev, trig)) {
  213. led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
  214. led_trigger_set(led_cdev, trig);
  215. break;
  216. }
  217. }
  218. up_write(&led_cdev->trigger_lock);
  219. up_read(&triggers_list_lock);
  220. }
  221. EXPORT_SYMBOL_GPL(led_trigger_set_default);
  222. void led_trigger_rename_static(const char *name, struct led_trigger *trig)
  223. {
  224. /* new name must be on a temporary string to prevent races */
  225. BUG_ON(name == trig->name);
  226. down_write(&triggers_list_lock);
  227. /* this assumes that trig->name was originaly allocated to
  228. * non constant storage */
  229. strcpy((char *)trig->name, name);
  230. up_write(&triggers_list_lock);
  231. }
  232. EXPORT_SYMBOL_GPL(led_trigger_rename_static);
  233. /* LED Trigger Interface */
  234. int led_trigger_register(struct led_trigger *trig)
  235. {
  236. struct led_classdev *led_cdev;
  237. struct led_trigger *_trig;
  238. rwlock_init(&trig->leddev_list_lock);
  239. INIT_LIST_HEAD(&trig->led_cdevs);
  240. down_write(&triggers_list_lock);
  241. /* Make sure the trigger's name isn't already in use */
  242. list_for_each_entry(_trig, &trigger_list, next_trig) {
  243. if (!strcmp(_trig->name, trig->name) &&
  244. (trig->trigger_type == _trig->trigger_type ||
  245. !trig->trigger_type || !_trig->trigger_type)) {
  246. up_write(&triggers_list_lock);
  247. return -EEXIST;
  248. }
  249. }
  250. /* Add to the list of led triggers */
  251. list_add_tail(&trig->next_trig, &trigger_list);
  252. up_write(&triggers_list_lock);
  253. /* Register with any LEDs that have this as a default trigger */
  254. down_read(&leds_list_lock);
  255. list_for_each_entry(led_cdev, &leds_list, node) {
  256. down_write(&led_cdev->trigger_lock);
  257. if (!led_cdev->trigger && led_cdev->default_trigger &&
  258. !strcmp(led_cdev->default_trigger, trig->name) &&
  259. trigger_relevant(led_cdev, trig)) {
  260. led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
  261. led_trigger_set(led_cdev, trig);
  262. }
  263. up_write(&led_cdev->trigger_lock);
  264. }
  265. up_read(&leds_list_lock);
  266. return 0;
  267. }
  268. EXPORT_SYMBOL_GPL(led_trigger_register);
  269. void led_trigger_unregister(struct led_trigger *trig)
  270. {
  271. struct led_classdev *led_cdev;
  272. if (list_empty_careful(&trig->next_trig))
  273. return;
  274. /* Remove from the list of led triggers */
  275. down_write(&triggers_list_lock);
  276. list_del_init(&trig->next_trig);
  277. up_write(&triggers_list_lock);
  278. /* Remove anyone actively using this trigger */
  279. down_read(&leds_list_lock);
  280. list_for_each_entry(led_cdev, &leds_list, node) {
  281. down_write(&led_cdev->trigger_lock);
  282. if (led_cdev->trigger == trig)
  283. led_trigger_set(led_cdev, NULL);
  284. up_write(&led_cdev->trigger_lock);
  285. }
  286. up_read(&leds_list_lock);
  287. }
  288. EXPORT_SYMBOL_GPL(led_trigger_unregister);
  289. static void devm_led_trigger_release(struct device *dev, void *res)
  290. {
  291. led_trigger_unregister(*(struct led_trigger **)res);
  292. }
  293. int devm_led_trigger_register(struct device *dev,
  294. struct led_trigger *trig)
  295. {
  296. struct led_trigger **dr;
  297. int rc;
  298. dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
  299. GFP_KERNEL);
  300. if (!dr)
  301. return -ENOMEM;
  302. *dr = trig;
  303. rc = led_trigger_register(trig);
  304. if (rc)
  305. devres_free(dr);
  306. else
  307. devres_add(dev, dr);
  308. return rc;
  309. }
  310. EXPORT_SYMBOL_GPL(devm_led_trigger_register);
  311. /* Simple LED Trigger Interface */
  312. void led_trigger_event(struct led_trigger *trig,
  313. enum led_brightness brightness)
  314. {
  315. struct led_classdev *led_cdev;
  316. unsigned long flags;
  317. if (!trig)
  318. return;
  319. read_lock_irqsave(&trig->leddev_list_lock, flags);
  320. list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
  321. led_set_brightness(led_cdev, brightness);
  322. read_unlock_irqrestore(&trig->leddev_list_lock, flags);
  323. }
  324. EXPORT_SYMBOL_GPL(led_trigger_event);
  325. static void led_trigger_blink_setup(struct led_trigger *trig,
  326. unsigned long *delay_on,
  327. unsigned long *delay_off,
  328. int oneshot,
  329. int invert)
  330. {
  331. struct led_classdev *led_cdev;
  332. unsigned long flags;
  333. if (!trig)
  334. return;
  335. read_lock_irqsave(&trig->leddev_list_lock, flags);
  336. list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
  337. if (oneshot)
  338. led_blink_set_oneshot(led_cdev, delay_on, delay_off,
  339. invert);
  340. else
  341. led_blink_set(led_cdev, delay_on, delay_off);
  342. }
  343. read_unlock_irqrestore(&trig->leddev_list_lock, flags);
  344. }
  345. void led_trigger_blink(struct led_trigger *trig,
  346. unsigned long *delay_on,
  347. unsigned long *delay_off)
  348. {
  349. led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
  350. }
  351. EXPORT_SYMBOL_GPL(led_trigger_blink);
  352. void led_trigger_blink_oneshot(struct led_trigger *trig,
  353. unsigned long *delay_on,
  354. unsigned long *delay_off,
  355. int invert)
  356. {
  357. led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
  358. }
  359. EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);
  360. void led_trigger_register_simple(const char *name, struct led_trigger **tp)
  361. {
  362. struct led_trigger *trig;
  363. int err;
  364. trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
  365. if (trig) {
  366. trig->name = name;
  367. err = led_trigger_register(trig);
  368. if (err < 0) {
  369. kfree(trig);
  370. trig = NULL;
  371. pr_warn("LED trigger %s failed to register (%d)\n",
  372. name, err);
  373. }
  374. } else {
  375. pr_warn("LED trigger %s failed to register (no memory)\n",
  376. name);
  377. }
  378. *tp = trig;
  379. }
  380. EXPORT_SYMBOL_GPL(led_trigger_register_simple);
  381. void led_trigger_unregister_simple(struct led_trigger *trig)
  382. {
  383. if (trig)
  384. led_trigger_unregister(trig);
  385. kfree(trig);
  386. }
  387. EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);