71 lines
2.5 KiB
C#
71 lines
2.5 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Collections.ObjectModel;
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using System.Linq;
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using Unosquare.RaspberryIO.Abstractions;
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namespace Unosquare.WiringPi {
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/// <inheritdoc />
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/// <summary>
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/// A simple wrapper for the I2c bus on the Raspberry Pi.
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/// </summary>
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public class I2CBus : II2CBus {
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// TODO: It would be nice to integrate i2c device detection.
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private static readonly Object SyncRoot = new Object();
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private readonly Dictionary<Int32, II2CDevice> _devices = new Dictionary<Int32, II2CDevice>();
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/// <inheritdoc />
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public ReadOnlyCollection<II2CDevice> Devices {
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get {
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lock(SyncRoot) {
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return new ReadOnlyCollection<II2CDevice>(this._devices.Values.ToArray());
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}
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}
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}
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/// <inheritdoc />
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public II2CDevice this[Int32 deviceId] => this.GetDeviceById(deviceId);
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/// <inheritdoc />
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public II2CDevice GetDeviceById(Int32 deviceId) {
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lock(SyncRoot) {
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return this._devices[deviceId];
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}
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}
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/// <inheritdoc />
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/// <exception cref="KeyNotFoundException">When the device file descriptor is not found.</exception>
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public II2CDevice AddDevice(Int32 deviceId) {
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lock(SyncRoot) {
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if(this._devices.ContainsKey(deviceId)) {
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return this._devices[deviceId];
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}
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Int32 fileDescriptor = SetupFileDescriptor(deviceId);
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if(fileDescriptor < 0) {
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throw new KeyNotFoundException($"Device with id {deviceId} could not be registered with the I2C bus. Error Code: {fileDescriptor}.");
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}
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I2CDevice device = new I2CDevice(deviceId, fileDescriptor);
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this._devices[deviceId] = device;
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return device;
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}
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}
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/// <summary>
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/// This initializes the I2C system with your given device identifier.
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/// The ID is the I2C number of the device and you can use the i2cdetect program to find this out.
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/// wiringPiI2CSetup() will work out which revision Raspberry Pi you have and open the appropriate device in /dev.
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/// The return value is the standard Linux filehandle, or -1 if any error – in which case, you can consult errno as usual.
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/// </summary>
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/// <param name="deviceId">The device identifier.</param>
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/// <returns>The Linux file handle.</returns>
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private static Int32 SetupFileDescriptor(Int32 deviceId) {
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lock(SyncRoot) {
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return Native.WiringPi.WiringPiI2CSetup(deviceId);
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}
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}
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}
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}
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