com.diozero.internal.provider.sysfs.NativeI2CDeviceSysFs Maven / Gradle / Ivy
package com.diozero.internal.provider.sysfs;
/*
* #%L
* Organisation: diozero
* Project: Device I/O Zero - Core
* Filename: NativeI2CDeviceSysFs.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
* in the Software without restriction, including without limitation the rights
* 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.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* THE SOFTWARE.
* #L%
*/
import java.io.IOException;
import java.io.RandomAccessFile;
import org.tinylog.Logger;
import com.diozero.api.DeviceBusyException;
import com.diozero.api.I2CDevice;
import com.diozero.util.FileUtil;
import com.diozero.util.RuntimeIOException;
/**
* Native Java implementation of the I2C SMBus commands using sysfs and a single native method to select the slave address.
*
* Reference Kernel I2C dev interface
* and SMBus Protocol.
* Warning Not all methods have been tested!
*/
public class NativeI2CDeviceSysFs implements I2CSMBusInterface {
private static final int EBUSY = -16;
private RandomAccessFile deviceFile;
private int controller;
private int deviceAddress;
public NativeI2CDeviceSysFs(int controller, int deviceAddress, boolean force) {
this.controller = controller;
this.deviceAddress = deviceAddress;
String device_file = "/dev/i2c-" + controller;
try {
deviceFile = new RandomAccessFile(device_file, "rwd");
int fd = FileUtil.getNativeFileDescriptor(deviceFile.getFD());
int rc = NativeI2C.selectSlave(fd, deviceAddress, force);
if (rc < 0) {
close();
if (rc == EBUSY) {
throw new DeviceBusyException("Error, I2C device " + controller + "-0x"
+ Integer.toHexString(deviceAddress) + " is busy");
}
throw new RuntimeIOException("Error selecting I2C address " + controller + "-0x"
+ Integer.toHexString(deviceAddress) + ": " + rc);
}
} catch (IOException e) {
close();
throw new RuntimeIOException(
"Error opening I2C device " + controller + "-0x" + Integer.toHexString(deviceAddress), e);
}
}
@Override
public void close() {
if (deviceFile != null) {
try {
deviceFile.close();
} catch (IOException e) {
Logger.error(e, "Error closing I2C device {}-0x{}: {}", Integer.valueOf(controller),
Integer.toHexString(deviceAddress), e);
}
}
}
@Override
public boolean probe(I2CDevice.ProbeMode mode) {
try {
return deviceFile.readUnsignedByte() >= 0;
} catch (IOException e) {
return false;
}
}
@Override
public void writeQuick(byte bit) {
throw new UnsupportedOperationException("I2C write quick isn't possible via sysfs");
}
@Override
public byte readByte() {
try {
return (byte) deviceFile.readUnsignedByte();
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C readByte for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public void writeByte(byte data) {
try {
deviceFile.writeByte(data & 0xff);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C writeByte for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public byte[] readBytes(int length) {
byte[] buffer = new byte[length];
try {
deviceFile.readFully(buffer);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C readBytes for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
return buffer;
}
@Override
public void writeBytes(byte[] data) {
try {
deviceFile.write(data);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C readBytes for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public byte readByteData(int register) {
try {
deviceFile.writeByte(register);
return (byte) deviceFile.readUnsignedByte();
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C readByteData for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public void writeByteData(int register, byte data) {
byte [] buffer = new byte[2];
buffer[0] = (byte) register;
buffer[1] = data;
try {
deviceFile.write(buffer);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C writeByteData for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public short readWordData(int register) {
try {
deviceFile.writeByte(register);
return deviceFile.readShort();
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C readWordData for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public void writeWordData(int register, short data) {
byte [] buffer = new byte[3];
buffer[0] = (byte) register;
buffer[1] = (byte) (data & 0xff);
buffer[2] = (byte) ((data >> 8) & 0xff);
try {
deviceFile.write(buffer);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C writeWordData for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public short processCall(int register, short data) {
writeWordData(register, data);
try {
return deviceFile.readShort();
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C processCall for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public byte[] readBlockData(int register) {
byte[] rx_data;
try {
deviceFile.write(register);
byte[] buffer = new byte[MAX_I2C_BLOCK_SIZE+1];
deviceFile.readFully(buffer);
int read = buffer[0] & 0xff;
rx_data = new byte[read];
System.arraycopy(buffer, 1, rx_data, 0, read);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C readBlockData for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
return rx_data;
}
@Override
public void writeBlockData(int register, byte[] data) {
byte[] buffer = new byte[data.length+2];
buffer[0] = (byte) register;
buffer[1] = (byte) data.length;
System.arraycopy(data, 0, buffer, 2, data.length);
try {
deviceFile.write(buffer);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C writeBlockData for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
@Override
public byte[] blockProcessCall(int register, byte[] data, int length) {
writeBlockData(register, data);
byte[] buffer = new byte[length];
try {
deviceFile.readFully(buffer);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C blockProcessCall for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
return buffer;
}
@Override
public byte[] readI2CBlockData(int register, int length) {
if (length >= MAX_I2C_BLOCK_SIZE) {
length = MAX_I2C_BLOCK_SIZE;
}
byte[] buffer = new byte[length];
try {
deviceFile.write(register);
deviceFile.readFully(buffer);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C readI2CBlockData for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
return buffer;
}
@Override
public void writeI2CBlockData(int register, byte[] data) {
byte[] buffer = new byte[data.length+1];
buffer[0] = (byte) register;
System.arraycopy(data, 0, buffer, 1, data.length);
try {
deviceFile.write(buffer);
} catch (IOException e) {
throw new RuntimeIOException("Error in I2C writeI2CBlockData for device i2c-" + controller + "-0x"
+ Integer.toHexString(deviceAddress), e);
}
}
}