// SPDX-License-Identifier: GPL-2.0-only /* * LED Triggers Core * * Copyright 2005-2007 Openedhand Ltd. * * Author: Richard Purdie */ #include #include #include #include #include #include #include #include #include #include #include "leds.h" /* * Nests outside led_cdev->trigger_lock */ static DECLARE_RWSEM(triggers_list_lock); static LIST_HEAD(trigger_list); /* Used by LED Class */ static inline bool trigger_relevant(struct led_classdev *led_cdev, struct led_trigger *trig) { return !trig->trigger_type || trig->trigger_type == led_cdev->trigger_type; } ssize_t led_trigger_write(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t pos, size_t count) { struct device *dev = kobj_to_dev(kobj); struct led_classdev *led_cdev = dev_get_drvdata(dev); struct led_trigger *trig; int ret = count; mutex_lock(&led_cdev->led_access); if (led_sysfs_is_disabled(led_cdev)) { ret = -EBUSY; goto unlock; } if (sysfs_streq(buf, "none")) { led_trigger_remove(led_cdev); goto unlock; } down_read(&triggers_list_lock); list_for_each_entry(trig, &trigger_list, next_trig) { if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) { down_write(&led_cdev->trigger_lock); led_trigger_set(led_cdev, trig); up_write(&led_cdev->trigger_lock); up_read(&triggers_list_lock); goto unlock; } } /* we come here only if buf matches no trigger */ ret = -EINVAL; up_read(&triggers_list_lock); unlock: mutex_unlock(&led_cdev->led_access); return ret; } EXPORT_SYMBOL_GPL(led_trigger_write); __printf(3, 4) static int led_trigger_snprintf(char *buf, ssize_t size, const char *fmt, ...) { va_list args; int i; va_start(args, fmt); if (size <= 0) i = vsnprintf(NULL, 0, fmt, args); else i = vscnprintf(buf, size, fmt, args); va_end(args); return i; } static int led_trigger_format(char *buf, size_t size, struct led_classdev *led_cdev) { struct led_trigger *trig; int len = led_trigger_snprintf(buf, size, "%s", led_cdev->trigger ? "none" : "[none]"); list_for_each_entry(trig, &trigger_list, next_trig) { bool hit; if (!trigger_relevant(led_cdev, trig)) continue; hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name); len += led_trigger_snprintf(buf + len, size - len, " %s%s%s", hit ? "[" : "", trig->name, hit ? "]" : ""); } len += led_trigger_snprintf(buf + len, size - len, "\n"); return len; } /* * It was stupid to create 10000 cpu triggers, but we are stuck with it now. * Don't make that mistake again. We work around it here by creating binary * attribute, which is not limited by length. This is _not_ good design, do not * copy it. */ ssize_t led_trigger_read(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t pos, size_t count) { struct device *dev = kobj_to_dev(kobj); struct led_classdev *led_cdev = dev_get_drvdata(dev); void *data; int len; down_read(&triggers_list_lock); down_read(&led_cdev->trigger_lock); len = led_trigger_format(NULL, 0, led_cdev); data = kvmalloc(len + 1, GFP_KERNEL); if (!data) { up_read(&led_cdev->trigger_lock); up_read(&triggers_list_lock); return -ENOMEM; } len = led_trigger_format(data, len + 1, led_cdev); up_read(&led_cdev->trigger_lock); up_read(&triggers_list_lock); len = memory_read_from_buffer(buf, count, &pos, data, len); kvfree(data); return len; } EXPORT_SYMBOL_GPL(led_trigger_read); /* Caller must ensure led_cdev->trigger_lock held */ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig) { char *event = NULL; char *envp[2]; const char *name; int ret; if (!led_cdev->trigger && !trig) return 0; name = trig ? trig->name : "none"; event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name); /* Remove any existing trigger */ if (led_cdev->trigger) { spin_lock(&led_cdev->trigger->leddev_list_lock); list_del_rcu(&led_cdev->trig_list); spin_unlock(&led_cdev->trigger->leddev_list_lock); /* ensure it's no longer visible on the led_cdevs list */ synchronize_rcu(); cancel_work_sync(&led_cdev->set_brightness_work); led_stop_software_blink(led_cdev); device_remove_groups(led_cdev->dev, led_cdev->trigger->groups); if (led_cdev->trigger->deactivate) led_cdev->trigger->deactivate(led_cdev); led_cdev->trigger = NULL; led_cdev->trigger_data = NULL; led_cdev->activated = false; led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER; led_set_brightness(led_cdev, LED_OFF); } if (trig) { spin_lock(&trig->leddev_list_lock); list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs); spin_unlock(&trig->leddev_list_lock); led_cdev->trigger = trig; /* * Some activate() calls use led_trigger_event() to initialize * the brightness of the LED for which the trigger is being set. * Ensure the led_cdev is visible on trig->led_cdevs for this. */ synchronize_rcu(); ret = 0; if (trig->activate) ret = trig->activate(led_cdev); else led_set_brightness(led_cdev, trig->brightness); if (ret) goto err_activate; ret = device_add_groups(led_cdev->dev, trig->groups); if (ret) { dev_err(led_cdev->dev, "Failed to add trigger attributes\n"); goto err_add_groups; } } if (event) { envp[0] = event; envp[1] = NULL; if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp)) dev_err(led_cdev->dev, "%s: Error sending uevent\n", __func__); kfree(event); } return 0; err_add_groups: if (trig->deactivate) trig->deactivate(led_cdev); err_activate: spin_lock(&led_cdev->trigger->leddev_list_lock); list_del_rcu(&led_cdev->trig_list); spin_unlock(&led_cdev->trigger->leddev_list_lock); synchronize_rcu(); led_cdev->trigger = NULL; led_cdev->trigger_data = NULL; led_set_brightness(led_cdev, LED_OFF); kfree(event); return ret; } EXPORT_SYMBOL_GPL(led_trigger_set); void led_trigger_remove(struct led_classdev *led_cdev) { down_write(&led_cdev->trigger_lock); led_trigger_set(led_cdev, NULL); up_write(&led_cdev->trigger_lock); } EXPORT_SYMBOL_GPL(led_trigger_remove); static bool led_match_default_trigger(struct led_classdev *led_cdev, struct led_trigger *trig) { if (!strcmp(led_cdev->default_trigger, trig->name) && trigger_relevant(led_cdev, trig)) { led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER; led_trigger_set(led_cdev, trig); return true; } return false; } void led_trigger_set_default(struct led_classdev *led_cdev) { struct led_trigger *trig; bool found = false; if (!led_cdev->default_trigger) return; down_read(&triggers_list_lock); down_write(&led_cdev->trigger_lock); list_for_each_entry(trig, &trigger_list, next_trig) { found = led_match_default_trigger(led_cdev, trig); if (found) break; } up_write(&led_cdev->trigger_lock); up_read(&triggers_list_lock); /* * If default trigger wasn't found, maybe trigger module isn't loaded yet. * Once loaded it will re-probe with all led_cdev's. */ if (!found) request_module_nowait("ledtrig:%s", led_cdev->default_trigger); } EXPORT_SYMBOL_GPL(led_trigger_set_default); /* LED Trigger Interface */ int led_trigger_register(struct led_trigger *trig) { struct led_classdev *led_cdev; struct led_trigger *_trig; spin_lock_init(&trig->leddev_list_lock); INIT_LIST_HEAD(&trig->led_cdevs); down_write(&triggers_list_lock); /* Make sure the trigger's name isn't already in use */ list_for_each_entry(_trig, &trigger_list, next_trig) { if (!strcmp(_trig->name, trig->name) && (trig->trigger_type == _trig->trigger_type || !trig->trigger_type || !_trig->trigger_type)) { up_write(&triggers_list_lock); return -EEXIST; } } /* Add to the list of led triggers */ list_add_tail(&trig->next_trig, &trigger_list); up_write(&triggers_list_lock); /* Register with any LEDs that have this as a default trigger */ down_read(&leds_list_lock); list_for_each_entry(led_cdev, &leds_list, node) { down_write(&led_cdev->trigger_lock); if (!led_cdev->trigger && led_cdev->default_trigger) led_match_default_trigger(led_cdev, trig); up_write(&led_cdev->trigger_lock); } up_read(&leds_list_lock); return 0; } EXPORT_SYMBOL_GPL(led_trigger_register); void led_trigger_unregister(struct led_trigger *trig) { struct led_classdev *led_cdev; if (list_empty_careful(&trig->next_trig)) return; /* Remove from the list of led triggers */ down_write(&triggers_list_lock); list_del_init(&trig->next_trig); up_write(&triggers_list_lock); /* Remove anyone actively using this trigger */ down_read(&leds_list_lock); list_for_each_entry(led_cdev, &leds_list, node) { down_write(&led_cdev->trigger_lock); if (led_cdev->trigger == trig) led_trigger_set(led_cdev, NULL); up_write(&led_cdev->trigger_lock); } up_read(&leds_list_lock); } EXPORT_SYMBOL_GPL(led_trigger_unregister); static void devm_led_trigger_release(struct device *dev, void *res) { led_trigger_unregister(*(struct led_trigger **)res); } int devm_led_trigger_register(struct device *dev, struct led_trigger *trig) { struct led_trigger **dr; int rc; dr = devres_alloc(devm_led_trigger_release, sizeof(*dr), GFP_KERNEL); if (!dr) return -ENOMEM; *dr = trig; rc = led_trigger_register(trig); if (rc) devres_free(dr); else devres_add(dev, dr); return rc; } EXPORT_SYMBOL_GPL(devm_led_trigger_register); /* Simple LED Trigger Interface */ void led_trigger_event(struct led_trigger *trig, enum led_brightness brightness) { struct led_classdev *led_cdev; if (!trig) return; trig->brightness = brightness; rcu_read_lock(); list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) led_set_brightness(led_cdev, brightness); rcu_read_unlock(); } EXPORT_SYMBOL_GPL(led_trigger_event); void led_mc_trigger_event(struct led_trigger *trig, unsigned int *intensity_value, unsigned int num_colors, enum led_brightness brightness) { struct led_classdev *led_cdev; if (!trig) return; rcu_read_lock(); list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) { if (!(led_cdev->flags & LED_MULTI_COLOR)) continue; led_mc_set_brightness(led_cdev, intensity_value, num_colors, brightness); } rcu_read_unlock(); } EXPORT_SYMBOL_GPL(led_mc_trigger_event); static void led_trigger_blink_setup(struct led_trigger *trig, unsigned long delay_on, unsigned long delay_off, int oneshot, int invert) { struct led_classdev *led_cdev; if (!trig) return; rcu_read_lock(); list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) { if (oneshot) led_blink_set_oneshot(led_cdev, &delay_on, &delay_off, invert); else led_blink_set_nosleep(led_cdev, delay_on, delay_off); } rcu_read_unlock(); } void led_trigger_blink(struct led_trigger *trig, unsigned long delay_on, unsigned long delay_off) { led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0); } EXPORT_SYMBOL_GPL(led_trigger_blink); void led_trigger_blink_oneshot(struct led_trigger *trig, unsigned long delay_on, unsigned long delay_off, int invert) { led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert); } EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot); void led_trigger_register_simple(const char *name, struct led_trigger **tp) { struct led_trigger *trig; int err; trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL); if (trig) { trig->name = name; err = led_trigger_register(trig); if (err < 0) { kfree(trig); trig = NULL; pr_warn("LED trigger %s failed to register (%d)\n", name, err); } } else { pr_warn("LED trigger %s failed to register (no memory)\n", name); } *tp = trig; } EXPORT_SYMBOL_GPL(led_trigger_register_simple); void led_trigger_unregister_simple(struct led_trigger *trig) { if (trig) led_trigger_unregister(trig); kfree(trig); } EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);