| // SPDX-License-Identifier: GPL-2.0 |
| // |
| // LED Kernel Transient Trigger |
| // |
| // Transient trigger allows one shot timer activation. Please refer to |
| // Documentation/leds/ledtrig-transient.txt for details |
| // Copyright (C) 2012 Shuah Khan <shuahkhan@gmail.com> |
| // |
| // Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's |
| // ledtrig-heartbeat.c |
| // Design and use-case input from Jonas Bonn <jonas@southpole.se> and |
| // Neil Brown <neilb@suse.de> |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/device.h> |
| #include <linux/slab.h> |
| #include <linux/timer.h> |
| #include <linux/leds.h> |
| #include "../leds.h" |
| |
| struct transient_trig_data { |
| int activate; |
| int state; |
| int restore_state; |
| unsigned long duration; |
| struct timer_list timer; |
| struct led_classdev *led_cdev; |
| }; |
| |
| static void transient_timer_function(struct timer_list *t) |
| { |
| struct transient_trig_data *transient_data = |
| from_timer(transient_data, t, timer); |
| struct led_classdev *led_cdev = transient_data->led_cdev; |
| |
| transient_data->activate = 0; |
| led_set_brightness_nosleep(led_cdev, transient_data->restore_state); |
| } |
| |
| static ssize_t transient_activate_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct transient_trig_data *transient_data = |
| led_trigger_get_drvdata(dev); |
| |
| return sprintf(buf, "%d\n", transient_data->activate); |
| } |
| |
| static ssize_t transient_activate_store(struct device *dev, |
| struct device_attribute *attr, const char *buf, size_t size) |
| { |
| struct led_classdev *led_cdev = led_trigger_get_led(dev); |
| struct transient_trig_data *transient_data = |
| led_trigger_get_drvdata(dev); |
| unsigned long state; |
| ssize_t ret; |
| |
| ret = kstrtoul(buf, 10, &state); |
| if (ret) |
| return ret; |
| |
| if (state != 1 && state != 0) |
| return -EINVAL; |
| |
| /* cancel the running timer */ |
| if (state == 0 && transient_data->activate == 1) { |
| del_timer(&transient_data->timer); |
| transient_data->activate = state; |
| led_set_brightness_nosleep(led_cdev, |
| transient_data->restore_state); |
| return size; |
| } |
| |
| /* start timer if there is no active timer */ |
| if (state == 1 && transient_data->activate == 0 && |
| transient_data->duration != 0) { |
| transient_data->activate = state; |
| led_set_brightness_nosleep(led_cdev, transient_data->state); |
| transient_data->restore_state = |
| (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL; |
| mod_timer(&transient_data->timer, |
| jiffies + msecs_to_jiffies(transient_data->duration)); |
| } |
| |
| /* state == 0 && transient_data->activate == 0 |
| timer is not active - just return */ |
| /* state == 1 && transient_data->activate == 1 |
| timer is already active - just return */ |
| |
| return size; |
| } |
| |
| static ssize_t transient_duration_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct transient_trig_data *transient_data = led_trigger_get_drvdata(dev); |
| |
| return sprintf(buf, "%lu\n", transient_data->duration); |
| } |
| |
| static ssize_t transient_duration_store(struct device *dev, |
| struct device_attribute *attr, const char *buf, size_t size) |
| { |
| struct transient_trig_data *transient_data = |
| led_trigger_get_drvdata(dev); |
| unsigned long state; |
| ssize_t ret; |
| |
| ret = kstrtoul(buf, 10, &state); |
| if (ret) |
| return ret; |
| |
| transient_data->duration = state; |
| return size; |
| } |
| |
| static ssize_t transient_state_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct transient_trig_data *transient_data = |
| led_trigger_get_drvdata(dev); |
| int state; |
| |
| state = (transient_data->state == LED_FULL) ? 1 : 0; |
| return sprintf(buf, "%d\n", state); |
| } |
| |
| static ssize_t transient_state_store(struct device *dev, |
| struct device_attribute *attr, const char *buf, size_t size) |
| { |
| struct transient_trig_data *transient_data = |
| led_trigger_get_drvdata(dev); |
| unsigned long state; |
| ssize_t ret; |
| |
| ret = kstrtoul(buf, 10, &state); |
| if (ret) |
| return ret; |
| |
| if (state != 1 && state != 0) |
| return -EINVAL; |
| |
| transient_data->state = (state == 1) ? LED_FULL : LED_OFF; |
| return size; |
| } |
| |
| static DEVICE_ATTR(activate, 0644, transient_activate_show, |
| transient_activate_store); |
| static DEVICE_ATTR(duration, 0644, transient_duration_show, |
| transient_duration_store); |
| static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store); |
| |
| static struct attribute *transient_trig_attrs[] = { |
| &dev_attr_activate.attr, |
| &dev_attr_duration.attr, |
| &dev_attr_state.attr, |
| NULL |
| }; |
| ATTRIBUTE_GROUPS(transient_trig); |
| |
| static int transient_trig_activate(struct led_classdev *led_cdev) |
| { |
| struct transient_trig_data *tdata; |
| |
| tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL); |
| if (!tdata) |
| return -ENOMEM; |
| |
| led_set_trigger_data(led_cdev, tdata); |
| tdata->led_cdev = led_cdev; |
| |
| timer_setup(&tdata->timer, transient_timer_function, 0); |
| |
| return 0; |
| } |
| |
| static void transient_trig_deactivate(struct led_classdev *led_cdev) |
| { |
| struct transient_trig_data *transient_data = led_get_trigger_data(led_cdev); |
| |
| del_timer_sync(&transient_data->timer); |
| led_set_brightness_nosleep(led_cdev, transient_data->restore_state); |
| kfree(transient_data); |
| } |
| |
| static struct led_trigger transient_trigger = { |
| .name = "transient", |
| .activate = transient_trig_activate, |
| .deactivate = transient_trig_deactivate, |
| .groups = transient_trig_groups, |
| }; |
| module_led_trigger(transient_trigger); |
| |
| MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>"); |
| MODULE_DESCRIPTION("Transient LED trigger"); |
| MODULE_LICENSE("GPL v2"); |