Validate Loopback

Loopback is essentially the test channel between TXFIFO and RXFIFO in IC. No external pin connections are required. Once loopback has been enabled, if you can write data in I2S TX, you can read data from I2S RX. The function is usually used in audio data recording scenarios.

# arecord -D hw:0,0 -r 16000 -c 2 -f S32_LE -t raw | aplay -D hw:0,1 -t raw -r 16000 -c 2 -f S32_LE