73 lines
2.6 KiB
C#
73 lines
2.6 KiB
C#
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namespace Unosquare.WiringPi
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{
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using Native;
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using RaspberryIO.Abstractions;
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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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/// <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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{
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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<int, II2CDevice> _devices = new Dictionary<int, II2CDevice>();
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/// <inheritdoc />
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public ReadOnlyCollection<II2CDevice> Devices
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{
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get
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{
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lock (SyncRoot)
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return new ReadOnlyCollection<II2CDevice>(_devices.Values.ToArray());
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}
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}
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/// <inheritdoc />
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public II2CDevice this[int deviceId] => GetDeviceById(deviceId);
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/// <inheritdoc />
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public II2CDevice GetDeviceById(int deviceId)
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{
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lock (SyncRoot)
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return _devices[deviceId];
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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(int deviceId)
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{
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lock (SyncRoot)
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{
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if (_devices.ContainsKey(deviceId))
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return _devices[deviceId];
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var 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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var device = new I2CDevice(deviceId, fileDescriptor);
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_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 int SetupFileDescriptor(int deviceId)
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{
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lock (SyncRoot)
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return WiringPi.WiringPiI2CSetup(deviceId);
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}
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}
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}
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