embedded – How to route sgtl5000 audio within the chip?

I have an embedded device with an sgtl5000 audio codec, linked to an iMX8 CPU via SPI.

According to the datasheet, there is a direct route from LINE_IN to HP_OUT, which avoids sound travelling through the SPI connection to the CPU.

Does ALSA/alsamixer allow me to do this routing, or is it restricted to only those audio flows which traverse the kernel?

Using amixer, I can see:

root@test217:~# amixer 
Simple mixer control 'Headphone',0
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 127
  Mono:
  Front Left: Playback 89 [70%] [-7.00dB] [on]
  Front Right: Playback 89 [70%] [-7.00dB] [on]
Simple mixer control 'Headphone Mux',0
  Capabilities: enum
  Items: 'DAC' 'LINE_IN'
  Item0: 'DAC'
...

What command lets me switch Headphone Mux>>Item0 from DAC to LINE_IN?