502 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * LED Triggers Core4 *5 * Copyright 2005-2007 Openedhand Ltd.6 *7 * Author: Richard Purdie <rpurdie@openedhand.com>8 */9 10#include <linux/export.h>11#include <linux/kernel.h>12#include <linux/list.h>13#include <linux/spinlock.h>14#include <linux/device.h>15#include <linux/timer.h>16#include <linux/rwsem.h>17#include <linux/leds.h>18#include <linux/slab.h>19#include <linux/mm.h>20#include "leds.h"21 22/*23 * Nests outside led_cdev->trigger_lock24 */25static DECLARE_RWSEM(triggers_list_lock);26static LIST_HEAD(trigger_list);27 28 /* Used by LED Class */29 30static inline bool31trigger_relevant(struct led_classdev *led_cdev, struct led_trigger *trig)32{33 return !trig->trigger_type || trig->trigger_type == led_cdev->trigger_type;34}35 36ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,37 struct bin_attribute *bin_attr, char *buf,38 loff_t pos, size_t count)39{40 struct device *dev = kobj_to_dev(kobj);41 struct led_classdev *led_cdev = dev_get_drvdata(dev);42 struct led_trigger *trig;43 int ret = count;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 if (sysfs_streq(buf, "none")) {53 led_trigger_remove(led_cdev);54 goto unlock;55 }56 57 down_read(&triggers_list_lock);58 list_for_each_entry(trig, &trigger_list, next_trig) {59 if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {60 down_write(&led_cdev->trigger_lock);61 led_trigger_set(led_cdev, trig);62 up_write(&led_cdev->trigger_lock);63 64 up_read(&triggers_list_lock);65 goto unlock;66 }67 }68 /* we come here only if buf matches no trigger */69 ret = -EINVAL;70 up_read(&triggers_list_lock);71 72unlock:73 mutex_unlock(&led_cdev->led_access);74 return ret;75}76EXPORT_SYMBOL_GPL(led_trigger_write);77 78__printf(3, 4)79static int led_trigger_snprintf(char *buf, ssize_t size, const char *fmt, ...)80{81 va_list args;82 int i;83 84 va_start(args, fmt);85 if (size <= 0)86 i = vsnprintf(NULL, 0, fmt, args);87 else88 i = vscnprintf(buf, size, fmt, args);89 va_end(args);90 91 return i;92}93 94static int led_trigger_format(char *buf, size_t size,95 struct led_classdev *led_cdev)96{97 struct led_trigger *trig;98 int len = led_trigger_snprintf(buf, size, "%s",99 led_cdev->trigger ? "none" : "[none]");100 101 list_for_each_entry(trig, &trigger_list, next_trig) {102 bool hit;103 104 if (!trigger_relevant(led_cdev, trig))105 continue;106 107 hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name);108 109 len += led_trigger_snprintf(buf + len, size - len,110 " %s%s%s", hit ? "[" : "",111 trig->name, hit ? "]" : "");112 }113 114 len += led_trigger_snprintf(buf + len, size - len, "\n");115 116 return len;117}118 119/*120 * It was stupid to create 10000 cpu triggers, but we are stuck with it now.121 * Don't make that mistake again. We work around it here by creating binary122 * attribute, which is not limited by length. This is _not_ good design, do not123 * copy it.124 */125ssize_t led_trigger_read(struct file *filp, struct kobject *kobj,126 struct bin_attribute *attr, char *buf,127 loff_t pos, size_t count)128{129 struct device *dev = kobj_to_dev(kobj);130 struct led_classdev *led_cdev = dev_get_drvdata(dev);131 void *data;132 int len;133 134 down_read(&triggers_list_lock);135 down_read(&led_cdev->trigger_lock);136 137 len = led_trigger_format(NULL, 0, led_cdev);138 data = kvmalloc(len + 1, GFP_KERNEL);139 if (!data) {140 up_read(&led_cdev->trigger_lock);141 up_read(&triggers_list_lock);142 return -ENOMEM;143 }144 len = led_trigger_format(data, len + 1, led_cdev);145 146 up_read(&led_cdev->trigger_lock);147 up_read(&triggers_list_lock);148 149 len = memory_read_from_buffer(buf, count, &pos, data, len);150 151 kvfree(data);152 153 return len;154}155EXPORT_SYMBOL_GPL(led_trigger_read);156 157/* Caller must ensure led_cdev->trigger_lock held */158int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)159{160 char *event = NULL;161 char *envp[2];162 const char *name;163 int ret;164 165 if (!led_cdev->trigger && !trig)166 return 0;167 168 name = trig ? trig->name : "none";169 event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);170 171 /* Remove any existing trigger */172 if (led_cdev->trigger) {173 spin_lock(&led_cdev->trigger->leddev_list_lock);174 list_del_rcu(&led_cdev->trig_list);175 spin_unlock(&led_cdev->trigger->leddev_list_lock);176 177 /* ensure it's no longer visible on the led_cdevs list */178 synchronize_rcu();179 180 cancel_work_sync(&led_cdev->set_brightness_work);181 led_stop_software_blink(led_cdev);182 device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);183 if (led_cdev->trigger->deactivate)184 led_cdev->trigger->deactivate(led_cdev);185 led_cdev->trigger = NULL;186 led_cdev->trigger_data = NULL;187 led_cdev->activated = false;188 led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;189 led_set_brightness(led_cdev, LED_OFF);190 }191 if (trig) {192 spin_lock(&trig->leddev_list_lock);193 list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs);194 spin_unlock(&trig->leddev_list_lock);195 led_cdev->trigger = trig;196 197 /*198 * Some activate() calls use led_trigger_event() to initialize199 * the brightness of the LED for which the trigger is being set.200 * Ensure the led_cdev is visible on trig->led_cdevs for this.201 */202 synchronize_rcu();203 204 /*205 * If "set brightness to 0" is pending in workqueue,206 * we don't want that to be reordered after ->activate()207 */208 flush_work(&led_cdev->set_brightness_work);209 210 ret = 0;211 if (trig->activate)212 ret = trig->activate(led_cdev);213 else214 led_set_brightness(led_cdev, trig->brightness);215 if (ret)216 goto err_activate;217 218 ret = device_add_groups(led_cdev->dev, trig->groups);219 if (ret) {220 dev_err(led_cdev->dev, "Failed to add trigger attributes\n");221 goto err_add_groups;222 }223 }224 225 if (event) {226 envp[0] = event;227 envp[1] = NULL;228 if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))229 dev_err(led_cdev->dev,230 "%s: Error sending uevent\n", __func__);231 kfree(event);232 }233 234 return 0;235 236err_add_groups:237 238 if (trig->deactivate)239 trig->deactivate(led_cdev);240err_activate:241 242 spin_lock(&led_cdev->trigger->leddev_list_lock);243 list_del_rcu(&led_cdev->trig_list);244 spin_unlock(&led_cdev->trigger->leddev_list_lock);245 synchronize_rcu();246 led_cdev->trigger = NULL;247 led_cdev->trigger_data = NULL;248 led_set_brightness(led_cdev, LED_OFF);249 kfree(event);250 251 return ret;252}253EXPORT_SYMBOL_GPL(led_trigger_set);254 255void led_trigger_remove(struct led_classdev *led_cdev)256{257 down_write(&led_cdev->trigger_lock);258 led_trigger_set(led_cdev, NULL);259 up_write(&led_cdev->trigger_lock);260}261EXPORT_SYMBOL_GPL(led_trigger_remove);262 263static bool led_match_default_trigger(struct led_classdev *led_cdev,264 struct led_trigger *trig)265{266 if (!strcmp(led_cdev->default_trigger, trig->name) &&267 trigger_relevant(led_cdev, trig)) {268 led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;269 led_trigger_set(led_cdev, trig);270 return true;271 }272 273 return false;274}275 276void led_trigger_set_default(struct led_classdev *led_cdev)277{278 struct led_trigger *trig;279 bool found = false;280 281 if (!led_cdev->default_trigger)282 return;283 284 down_read(&triggers_list_lock);285 down_write(&led_cdev->trigger_lock);286 list_for_each_entry(trig, &trigger_list, next_trig) {287 found = led_match_default_trigger(led_cdev, trig);288 if (found)289 break;290 }291 up_write(&led_cdev->trigger_lock);292 up_read(&triggers_list_lock);293 294 /*295 * If default trigger wasn't found, maybe trigger module isn't loaded yet.296 * Once loaded it will re-probe with all led_cdev's.297 */298 if (!found)299 request_module_nowait("ledtrig:%s", led_cdev->default_trigger);300}301EXPORT_SYMBOL_GPL(led_trigger_set_default);302 303/* LED Trigger Interface */304 305int led_trigger_register(struct led_trigger *trig)306{307 struct led_classdev *led_cdev;308 struct led_trigger *_trig;309 310 spin_lock_init(&trig->leddev_list_lock);311 INIT_LIST_HEAD(&trig->led_cdevs);312 313 down_write(&triggers_list_lock);314 /* Make sure the trigger's name isn't already in use */315 list_for_each_entry(_trig, &trigger_list, next_trig) {316 if (!strcmp(_trig->name, trig->name) &&317 (trig->trigger_type == _trig->trigger_type ||318 !trig->trigger_type || !_trig->trigger_type)) {319 up_write(&triggers_list_lock);320 return -EEXIST;321 }322 }323 /* Add to the list of led triggers */324 list_add_tail(&trig->next_trig, &trigger_list);325 up_write(&triggers_list_lock);326 327 /* Register with any LEDs that have this as a default trigger */328 down_read(&leds_list_lock);329 list_for_each_entry(led_cdev, &leds_list, node) {330 down_write(&led_cdev->trigger_lock);331 if (!led_cdev->trigger && led_cdev->default_trigger)332 led_match_default_trigger(led_cdev, trig);333 up_write(&led_cdev->trigger_lock);334 }335 up_read(&leds_list_lock);336 337 return 0;338}339EXPORT_SYMBOL_GPL(led_trigger_register);340 341void led_trigger_unregister(struct led_trigger *trig)342{343 struct led_classdev *led_cdev;344 345 if (list_empty_careful(&trig->next_trig))346 return;347 348 /* Remove from the list of led triggers */349 down_write(&triggers_list_lock);350 list_del_init(&trig->next_trig);351 up_write(&triggers_list_lock);352 353 /* Remove anyone actively using this trigger */354 down_read(&leds_list_lock);355 list_for_each_entry(led_cdev, &leds_list, node) {356 down_write(&led_cdev->trigger_lock);357 if (led_cdev->trigger == trig)358 led_trigger_set(led_cdev, NULL);359 up_write(&led_cdev->trigger_lock);360 }361 up_read(&leds_list_lock);362}363EXPORT_SYMBOL_GPL(led_trigger_unregister);364 365static void devm_led_trigger_release(struct device *dev, void *res)366{367 led_trigger_unregister(*(struct led_trigger **)res);368}369 370int devm_led_trigger_register(struct device *dev,371 struct led_trigger *trig)372{373 struct led_trigger **dr;374 int rc;375 376 dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),377 GFP_KERNEL);378 if (!dr)379 return -ENOMEM;380 381 *dr = trig;382 383 rc = led_trigger_register(trig);384 if (rc)385 devres_free(dr);386 else387 devres_add(dev, dr);388 389 return rc;390}391EXPORT_SYMBOL_GPL(devm_led_trigger_register);392 393/* Simple LED Trigger Interface */394 395void led_trigger_event(struct led_trigger *trig,396 enum led_brightness brightness)397{398 struct led_classdev *led_cdev;399 400 if (!trig)401 return;402 403 trig->brightness = brightness;404 405 rcu_read_lock();406 list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)407 led_set_brightness(led_cdev, brightness);408 rcu_read_unlock();409}410EXPORT_SYMBOL_GPL(led_trigger_event);411 412void led_mc_trigger_event(struct led_trigger *trig,413 unsigned int *intensity_value, unsigned int num_colors,414 enum led_brightness brightness)415{416 struct led_classdev *led_cdev;417 418 if (!trig)419 return;420 421 rcu_read_lock();422 list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {423 if (!(led_cdev->flags & LED_MULTI_COLOR))424 continue;425 426 led_mc_set_brightness(led_cdev, intensity_value, num_colors, brightness);427 }428 rcu_read_unlock();429}430EXPORT_SYMBOL_GPL(led_mc_trigger_event);431 432static void led_trigger_blink_setup(struct led_trigger *trig,433 unsigned long delay_on,434 unsigned long delay_off,435 int oneshot,436 int invert)437{438 struct led_classdev *led_cdev;439 440 if (!trig)441 return;442 443 rcu_read_lock();444 list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {445 if (oneshot)446 led_blink_set_oneshot(led_cdev, &delay_on, &delay_off,447 invert);448 else449 led_blink_set_nosleep(led_cdev, delay_on, delay_off);450 }451 rcu_read_unlock();452}453 454void led_trigger_blink(struct led_trigger *trig,455 unsigned long delay_on,456 unsigned long delay_off)457{458 led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);459}460EXPORT_SYMBOL_GPL(led_trigger_blink);461 462void led_trigger_blink_oneshot(struct led_trigger *trig,463 unsigned long delay_on,464 unsigned long delay_off,465 int invert)466{467 led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);468}469EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);470 471void led_trigger_register_simple(const char *name, struct led_trigger **tp)472{473 struct led_trigger *trig;474 int err;475 476 trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);477 478 if (trig) {479 trig->name = name;480 err = led_trigger_register(trig);481 if (err < 0) {482 kfree(trig);483 trig = NULL;484 pr_warn("LED trigger %s failed to register (%d)\n",485 name, err);486 }487 } else {488 pr_warn("LED trigger %s failed to register (no memory)\n",489 name);490 }491 *tp = trig;492}493EXPORT_SYMBOL_GPL(led_trigger_register_simple);494 495void led_trigger_unregister_simple(struct led_trigger *trig)496{497 if (trig)498 led_trigger_unregister(trig);499 kfree(trig);500}501EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);502