private unsafe void RdWrInterfaceTransfer(byte *writeBufferPtr, byte *readBufferPtr, int writeBufferLength, int readBufferLength)
{
int messageCount = 0;
if (writeBufferPtr != null)
{
messageCount++;
}
if (readBufferPtr != null)
{
messageCount++;
}
i2c_msg *messagesPtr = stackalloc i2c_msg[messageCount];
messageCount = 0;
if (writeBufferPtr != null)
{
messagesPtr[messageCount++] = new i2c_msg()
{
flags = I2cMessageFlags.I2C_M_WR,
addr = (ushort)_settings.DeviceAddress,
len = (ushort)writeBufferLength,
buf = writeBufferPtr
};
}
if (readBufferPtr != null)
{
messagesPtr[messageCount++] = new i2c_msg()
{
flags = I2cMessageFlags.I2C_M_RD,
addr = (ushort)_settings.DeviceAddress,
len = (ushort)readBufferLength,
buf = readBufferPtr
};
}
var tr = new i2c_rdwr_ioctl_data()
{
msgs = messagesPtr,
nmsgs = (uint)messageCount
};
int ret = ioctl(_deviceFileDescriptor, (uint)I2cSettings.I2C_RDWR, new IntPtr(&tr));
if (ret < 0)
{
throw Utils.CreateIOException("Error performing I2c data transfer", ret);
}
}
private unsafe void ReadWriteInterfaceTransfer(byte *writeBuffer, byte *readBuffer, int writeBufferLength, int readBufferLength)
{
// Allocating space for 2 messages in case we want to read and write on the same call.
i2c_msg *messagesPtr = stackalloc i2c_msg[2];
int messageCount = 0;
if (writeBuffer != null)
{
messagesPtr[messageCount++] = new i2c_msg()
{
flags = I2cMessageFlags.I2C_M_WR,
addr = (ushort)_settings.DeviceAddress,
len = (ushort)writeBufferLength,
buf = writeBuffer
};
}
if (readBuffer != null)
{
messagesPtr[messageCount++] = new i2c_msg()
{
flags = I2cMessageFlags.I2C_M_RD,
addr = (ushort)_settings.DeviceAddress,
len = (ushort)readBufferLength,
buf = readBuffer
};
}
var msgset = new i2c_rdwr_ioctl_data()
{
msgs = messagesPtr,
nmsgs = (uint)messageCount
};
int result = Interop.ioctl(_deviceFileDescriptor, (uint)I2cSettings.I2C_RDWR, new IntPtr(&msgset));
if (result < 0)
{
throw new IOException($"Error {Marshal.GetLastWin32Error()} performing I2C data transfer.");
}
}
