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