com.diozero.internal.provider.sysfs.SysFsDigitalOutputDevice Maven / Gradle / Ivy
package com.diozero.internal.provider.sysfs;
/*
* #%L
* Organisation: diozero
* Project: Device I/O Zero - Core
* Filename: SysFsDigitalOutputDevice.java
*
* This file is part of the diozero project. More information about this project
* can be found at http://www.diozero.com/
* %%
* Copyright (C) 2016 - 2020 diozero
* %%
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.file.Path;
import org.tinylog.Logger;
import com.diozero.api.DeviceMode;
import com.diozero.api.PinInfo;
import com.diozero.internal.provider.AbstractDevice;
import com.diozero.internal.provider.GpioDigitalOutputDeviceInterface;
import com.diozero.util.RuntimeIOException;
public class SysFsDigitalOutputDevice extends AbstractDevice implements GpioDigitalOutputDeviceInterface {
private static final String VALUE_FILE = "value";
private static final byte LOW_VALUE = '0';
private static final byte HIGH_VALUE = '1';
private SysFsDeviceFactory deviceFactory;
private int gpio;
private RandomAccessFile valueFile;
public SysFsDigitalOutputDevice(SysFsDeviceFactory deviceFactory, String key, PinInfo pinInfo, boolean initialValue) {
super(key, deviceFactory);
this.deviceFactory = deviceFactory;
this.gpio = pinInfo.getSysFsNumber();
deviceFactory.export(pinInfo.getSysFsNumber(), DeviceMode.DIGITAL_OUTPUT);
Path gpio_dir = deviceFactory.getGpioDirectoryPath(gpio);
// TODO Set active_low value to 0
try {
valueFile = new RandomAccessFile(gpio_dir.resolve(VALUE_FILE).toFile(), "rw");
} catch (IOException e) {
throw new RuntimeIOException("Error opening value file for GPIO " + gpio, e);
}
setValue(initialValue);
}
@Override
public int getGpio() {
return gpio;
}
@Override
public boolean getValue() throws RuntimeIOException {
try {
// Note seek(0) is required
valueFile.seek(0);
return valueFile.readByte() == HIGH_VALUE;
} catch (IOException e) {
throw new RuntimeIOException("Error reading value", e);
}
}
@Override
public void setValue(boolean value) throws RuntimeIOException {
try {
valueFile.seek(0);
valueFile.write(value ? HIGH_VALUE : LOW_VALUE);
} catch (IOException e) {
throw new RuntimeIOException("Error writing value", e);
}
}
@Override
protected void closeDevice() throws RuntimeIOException {
Logger.trace("closeDevice()");
try {
valueFile.close();
} catch (IOException e) {
throw new RuntimeIOException(e);
}
deviceFactory.unexport(gpio);
}
}