leds: add oneshot trigger
Add oneshot trigger to blink a led with configurale parameters via sysfs. Signed-off-by: Fabio Baltieri <fabio.baltieri@gmail.com> Cc: Shuah Khan <shuahkhan@gmail.com> Signed-off-by: Bryan Wu <bryan.wu@canonical.com>hifive-unleashed-5.1
Fabio Baltieri
Bryan Wu
parent
437864828d
commit
5e417281cd
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@ -0,0 +1,59 @@
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One-shot LED Trigger
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====================
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This is a LED trigger useful for signaling the user of an event where there are
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no clear trap points to put standard led-on and led-off settings. Using this
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trigger, the application needs only to signal the trigger when an event has
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happened, than the trigger turns the LED on and than keeps it off for a
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specified amount of time.
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This trigger is meant to be usable both for sporadic and dense events. In the
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first case, the trigger produces a clear single controlled blink for each
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event, while in the latter it keeps blinking at constant rate, as to signal
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that the events are arriving continuously.
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A one-shot LED only stays in a constant state when there are no events. An
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additional "invert" property specifies if the LED has to stay off (normal) or
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on (inverted) when not rearmed.
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The trigger can be activated from user space on led class devices as shown
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below:
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echo oneshot > trigger
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This adds the following sysfs attributes to the LED:
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delay_on - specifies for how many milliseconds the LED has to stay at
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LED_FULL brightness after it has been armed.
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Default to 100 ms.
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delay_off - specifies for how many milliseconds the LED has to stay at
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LED_OFF brightness after it has been armed.
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Default to 100 ms.
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invert - reverse the blink logic. If set to 0 (default) blink on for delay_on
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ms, then blink off for delay_off ms, leaving the LED normally off. If
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set to 1, blink off for delay_off ms, then blink on for delay_on ms,
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leaving the LED normally on.
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Setting this value also immediately change the LED state.
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shot - write any non-empty string to signal an events, this starts a blink
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sequence if not already running.
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Example use-case: network devices, initialization:
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echo oneshot > trigger # set trigger for this led
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echo 33 > delay_on # blink at 1 / (33 + 33) Hz on continuous traffic
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echo 33 > delay_off
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interface goes up:
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echo 1 > invert # set led as normally-on, turn the led on
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packet received/transmitted:
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echo 1 > shot # led starts blinking, ignored if already blinking
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interface goes down
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echo 0 > invert # set led as normally-off, turn the led off
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@ -443,6 +443,20 @@ config LEDS_TRIGGER_TIMER
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If unsure, say Y.
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config LEDS_TRIGGER_ONESHOT
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tristate "LED One-shot Trigger"
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depends on LEDS_TRIGGERS
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help
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This allows LEDs to blink in one-shot pulses with parameters
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controlled via sysfs. It's useful to notify the user on
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sporadic events, when there are no clear begin and end trap points,
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or on dense events, where this blinks the LED at constant rate if
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rearmed continuously.
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It also shows how to use the led_blink_set_oneshot() function.
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If unsure, say Y.
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config LEDS_TRIGGER_IDE_DISK
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bool "LED IDE Disk Trigger"
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depends on IDE_GD_ATA
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@ -53,6 +53,7 @@ obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
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# LED Triggers
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obj-$(CONFIG_LEDS_TRIGGER_TIMER) += ledtrig-timer.o
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obj-$(CONFIG_LEDS_TRIGGER_ONESHOT) += ledtrig-oneshot.o
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obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK) += ledtrig-ide-disk.o
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obj-$(CONFIG_LEDS_TRIGGER_HEARTBEAT) += ledtrig-heartbeat.o
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obj-$(CONFIG_LEDS_TRIGGER_BACKLIGHT) += ledtrig-backlight.o
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@ -0,0 +1,204 @@
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/*
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* One-shot LED Trigger
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*
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* Copyright 2012, Fabio Baltieri <fabio.baltieri@gmail.com>
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*
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* Based on ledtrig-timer.c by Richard Purdie <rpurdie@openedhand.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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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/ctype.h>
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#include <linux/slab.h>
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#include <linux/leds.h>
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#include "leds.h"
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#define DEFAULT_DELAY 100
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struct oneshot_trig_data {
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unsigned int invert;
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};
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static ssize_t led_shot(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 = dev_get_drvdata(dev);
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struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
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led_blink_set_oneshot(led_cdev,
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&led_cdev->blink_delay_on, &led_cdev->blink_delay_off,
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oneshot_data->invert);
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/* content is ignored */
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return size;
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}
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static ssize_t led_invert_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
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return sprintf(buf, "%u\n", oneshot_data->invert);
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}
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static ssize_t led_invert_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 = dev_get_drvdata(dev);
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struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
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unsigned long state;
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int ret;
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ret = kstrtoul(buf, 0, &state);
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if (ret)
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return ret;
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oneshot_data->invert = !!state;
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if (oneshot_data->invert)
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led_set_brightness(led_cdev, LED_FULL);
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else
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led_set_brightness(led_cdev, LED_OFF);
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return size;
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}
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static ssize_t led_delay_on_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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return sprintf(buf, "%lu\n", led_cdev->blink_delay_on);
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}
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static ssize_t led_delay_on_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 = dev_get_drvdata(dev);
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unsigned long state;
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int ret;
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ret = kstrtoul(buf, 0, &state);
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if (ret)
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return ret;
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led_cdev->blink_delay_on = state;
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return size;
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}
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static ssize_t led_delay_off_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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return sprintf(buf, "%lu\n", led_cdev->blink_delay_off);
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}
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static ssize_t led_delay_off_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 = dev_get_drvdata(dev);
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unsigned long state;
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int ret;
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ret = kstrtoul(buf, 0, &state);
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if (ret)
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return ret;
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led_cdev->blink_delay_off = state;
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return size;
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}
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static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
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static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
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static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
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static DEVICE_ATTR(shot, 0200, NULL, led_shot);
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static void oneshot_trig_activate(struct led_classdev *led_cdev)
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{
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struct oneshot_trig_data *oneshot_data;
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int rc;
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oneshot_data = kzalloc(sizeof(*oneshot_data), GFP_KERNEL);
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if (!oneshot_data)
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return;
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led_cdev->trigger_data = oneshot_data;
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rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
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if (rc)
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goto err_out_trig_data;
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rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
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if (rc)
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goto err_out_delayon;
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rc = device_create_file(led_cdev->dev, &dev_attr_invert);
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if (rc)
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goto err_out_delayoff;
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rc = device_create_file(led_cdev->dev, &dev_attr_shot);
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if (rc)
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goto err_out_invert;
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led_cdev->blink_delay_on = DEFAULT_DELAY;
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led_cdev->blink_delay_off = DEFAULT_DELAY;
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led_cdev->activated = true;
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return;
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err_out_invert:
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device_remove_file(led_cdev->dev, &dev_attr_invert);
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err_out_delayoff:
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device_remove_file(led_cdev->dev, &dev_attr_delay_off);
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err_out_delayon:
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device_remove_file(led_cdev->dev, &dev_attr_delay_on);
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err_out_trig_data:
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kfree(led_cdev->trigger_data);
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}
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static void oneshot_trig_deactivate(struct led_classdev *led_cdev)
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{
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struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
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if (led_cdev->activated) {
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device_remove_file(led_cdev->dev, &dev_attr_delay_on);
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device_remove_file(led_cdev->dev, &dev_attr_delay_off);
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device_remove_file(led_cdev->dev, &dev_attr_invert);
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device_remove_file(led_cdev->dev, &dev_attr_shot);
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kfree(oneshot_data);
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led_cdev->activated = false;
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}
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/* Stop blinking */
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led_brightness_set(led_cdev, LED_OFF);
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}
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static struct led_trigger oneshot_led_trigger = {
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.name = "oneshot",
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.activate = oneshot_trig_activate,
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.deactivate = oneshot_trig_deactivate,
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};
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static int __init oneshot_trig_init(void)
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{
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return led_trigger_register(&oneshot_led_trigger);
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}
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static void __exit oneshot_trig_exit(void)
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{
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led_trigger_unregister(&oneshot_led_trigger);
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}
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module_init(oneshot_trig_init);
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module_exit(oneshot_trig_exit);
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MODULE_AUTHOR("Fabio Baltieri <fabio.baltieri@gmail.com>");
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MODULE_DESCRIPTION("One-shot LED trigger");
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MODULE_LICENSE("GPL");
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