Source code

001package com.pi4j.io.i2c.impl;
002
003/*
004 * #%L
005 * **********************************************************************
006 * ORGANIZATION  :  Pi4J
007 * PROJECT       :  Pi4J :: Java Library (Core)
008 * FILENAME      :  I2CDeviceImpl.java
009 *
010 * This file is part of the Pi4J project. More information about
011 * this project can be found here:  https://www.pi4j.com/
012 * **********************************************************************
013 * %%
014 * Copyright (C) 2012 - 2021 Pi4J
015 * %%
016 * This program is free software: you can redistribute it and/or modify
017 * it under the terms of the GNU Lesser General Public License as
018 * published by the Free Software Foundation, either version 3 of the
019 * License, or (at your option) any later version.
020 *
021 * This program is distributed in the hope that it will be useful,
022 * but WITHOUT ANY WARRANTY; without even the implied warranty of
023 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
024 * GNU General Lesser Public License for more details.
025 *
026 * You should have received a copy of the GNU General Lesser Public
027 * License along with this program.  If not, see
028 * <http://www.gnu.org/licenses/lgpl-3.0.html>.
029 * #L%
030 */
031
032import java.io.IOException;
033import java.nio.ByteBuffer;
034import java.nio.IntBuffer;
035
036import com.pi4j.io.i2c.I2CDevice;
037
038/**
039 * Implementation of i2c device. This class only holds reference to i2c bus (so it can use its handle) and device address.
040 *
041 * @author Daniel Sendula, refactored by <a href="http://raspelikan.blogspot.co.at">RasPelikan</a>
042 *
043 */
044public class I2CDeviceImpl implements I2CDevice {
045    /**
046     * Reference to i2c bus
047     */
048    private I2CBusImpl bus;
049
050    /**
051     * I2c device address
052     */
053    private int deviceAddress;
054
055    /**
056     * @return The address for which this instance is constructed for.
057     */
058    @Override
059    public int getAddress() {
060        return deviceAddress;
061    }
062
063    /**
064     * Constructor.
065     *
066     * @param bus i2c bus
067     * @param address i2c device address
068     */
069    public I2CDeviceImpl(I2CBusImpl bus, int address) {
070        this.bus = bus;
071        this.deviceAddress = address;
072    }
073
074    /**
075     * Used by WriteRunnables and ReadRunnables.
076     *
077     * @return The bus associated with this I2CDeviceImpl instance.
078     */
079    I2CBusImpl getBus() {
080        return bus;
081    }
082
083    /**
084     * This method writes one byte to i2c device.
085     *
086     * @param data byte to be written
087     *
088     * @throws IOException thrown in case byte cannot be written to the i2c device or i2c bus
089     */
090    @Override
091    public void write(final byte data) throws IOException {
092        getBus().writeByteDirect(this, data);
093    }
094
095    /**
096     * This method writes several bytes to the i2c device from given buffer at given offset.
097     *
098     * @param data buffer of data to be written to the i2c device in one go
099     * @param offset offset in buffer
100     * @param size number of bytes to be written
101     *
102     * @throws IOException thrown in case byte cannot be written to the i2c device or i2c bus
103     */
104    @Override
105    public void write(final byte[] data, final int offset, final int size) throws IOException {
106        getBus().writeBytesDirect(this, size, offset, data);
107    }
108
109    /**
110     * This method writes all bytes included in the given buffer directly to the i2c device.
111     *
112     * @param buffer buffer of data to be written to the i2c device in one go
113     *
114     * @throws IOException thrown in case byte cannot be written to the i2c device or i2c bus
115     */
116    @Override
117    public void write(byte[] buffer) throws IOException {
118        write(buffer, 0, buffer.length);
119    }
120
121    /**
122     * This method writes one byte to i2c device.
123     *
124     * @param address local address in the i2c device
125     * @param data byte to be written
126     *
127     * @throws IOException thrown in case byte cannot be written to the i2c device or i2c bus
128     */
129    @Override
130    public void write(final int address, final byte data) throws IOException {
131        getBus().writeByte(this, address, data);
132    }
133
134    /**
135     * This method writes several bytes to the i2c device from given buffer at given offset.
136     *
137     * @param address local address in the i2c device
138     * @param data buffer of data to be written to the i2c device in one go
139     * @param offset offset in buffer
140     * @param size number of bytes to be written
141     *
142     * @throws IOException thrown in case byte cannot be written to the i2c device or i2c bus
143     */
144    @Override
145    public void write(final int address, final byte[] data, final int offset, final int size) throws IOException {
146        getBus().writeBytes(this, address, size, offset, data);
147    }
148
149    /**
150     * This method writes all bytes included in the given buffer directoy to the register address on the i2c device
151     *
152     * @param address local address in the i2c device
153     * @param buffer buffer of data to be written to the i2c device in one go
154     *
155     * @throws IOException thrown in case byte cannot be written to the i2c device or i2c bus
156     */
157    public void write(int address, byte[] buffer) throws IOException {
158        write(address, buffer, 0, buffer.length);
159    }
160
161    /**
162     * This method reads one byte from the i2c device. Result is between 0 and 255 if read operation was successful, else a negative number for an error.
163     *
164     * @return byte value read: positive number (or zero) to 255 if read was successful. Negative number if reading failed.
165     *
166     * @throws IOException thrown in case byte cannot be read from the i2c device or i2c bus
167     */
168    @Override
169    public int read() throws IOException {
170        return getBus().readByteDirect(this);
171    }
172
173    /**
174     * <p>
175     * This method reads bytes from the i2c device to given buffer at asked offset.
176     * </p>
177     *
178     * <p>
179     * Note: Current implementation calls {@link #read(int)}. That means for each read byte i2c bus will send (next) address to i2c device.
180     * </p>
181     *
182     * @param data buffer of data to be read from the i2c device in one go
183     * @param offset offset in buffer
184     * @param size number of bytes to be read
185     *
186     * @return number of bytes read
187     *
188     * @throws IOException thrown in case byte cannot be read from the i2c device or i2c bus
189     */
190    @Override
191    public int read(final byte[] data, final int offset, final int size) throws IOException {
192        return getBus().readBytesDirect(this, size, offset, data);
193    }
194
195    /**
196     * This method reads one byte from the i2c device. Result is between 0 and 255 if read operation was successful, else a negative number for an error.
197     *
198     * @param address local address in the i2c device
199     * @return byte value read: positive number (or zero) to 255 if read was successful. Negative number if reading failed.
200     *
201     * @throws IOException thrown in case byte cannot be read from the i2c device or i2c bus
202     */
203    @Override
204    public int read(final int address) throws IOException {
205        return getBus().readByte(this, address);
206    }
207
208    /**
209     * <p>
210     * This method reads bytes from the i2c device to given buffer at asked offset.
211     * </p>
212     *
213     * <p>
214     * Note: Current implementation calls {@link #read(int)}. That means for each read byte i2c bus will send (next) address to i2c device.
215     * </p>
216     *
217     * @param address local address in the i2c device
218     * @param data buffer of data to be read from the i2c device in one go
219     * @param offset offset in buffer
220     * @param size number of bytes to be read
221     *
222     * @return number of bytes read
223     *
224     * @throws IOException thrown in case byte cannot be read from the i2c device or i2c bus
225     */
226    @Override
227    public int read(final int address, final byte[] data, final int offset, final int size) throws IOException {
228        return getBus().readBytes(this, address, size, offset, data);
229    }
230
231    /**
232     * @see com.pi4j.io.file.LinuxFile#ioctl(long, int)
233     */
234    @Override
235    public void ioctl(long command, int value) throws IOException {
236        getBus().ioctl(this, command, value);
237    }
238
239    /**
240     * @see com.pi4j.io.file.LinuxFile#ioctl(long, ByteBuffer, IntBuffer)
241     */
242    @Override
243    public void ioctl(long command, ByteBuffer data, IntBuffer offsets) throws IOException {
244        getBus().ioctl(this, command, data, offsets);
245    }
246
247    /**
248     * This method writes and reads bytes to/from the i2c device in a single method call
249     *
250     * @param writeData buffer of data to be written to the i2c device in one go
251     * @param writeOffset offset in write buffer
252     * @param writeSize number of bytes to be written from buffer
253     * @param readData buffer of data to be read from the i2c device in one go
254     * @param readOffset offset in read buffer
255     * @param readSize number of bytes to be read
256     *
257     * @return number of bytes read
258     *
259     * @throws IOException thrown in case byte cannot be read from the i2c device or i2c bus
260     */
261    @Override
262    public int read(final byte[] writeData, final int writeOffset, final int writeSize, final byte[] readData, final int readOffset, final int readSize) throws IOException {
263        return getBus().writeAndReadBytesDirect(this, writeSize, writeOffset, writeData, readSize, readOffset, readData);
264    }
265
266    /**
267     * This helper method creates a string describing bus file name and device address (in hex).
268     *
269     * @return string with all details
270     */
271    protected String makeDescription() {
272        return "I2CDevice on " + bus + " at address 0x" + Integer.toHexString(deviceAddress);
273    }
274
275    /**
276     * This helper method creates a string describing bus file name, device address (in hex) and local i2c address.
277     *
278     * @param address local address in i2c device
279     * @return string with all details
280     */
281    protected String makeDescription(int address) {
282        return "I2CDevice on " + bus + " at address 0x" + Integer.toHexString(deviceAddress) + " to address 0x" + Integer.toHexString(address);
283    }
284}