ASoC: No stereo on Banana Pi M2 headphone jack

[Michael]

On Wed, Dec 30, 2020 at 11:58:14PM +0100, Michael wrote:
>Hi all,
>
>I'm in need for stereo sound on the headphone jack of a Banana Pi M2 
>(Allwinner A31s), but I'm getting only mono differential (I assume at 
>least, because I can hear both channels in either speaker).
>
>In alsamixer, there is a switch to select between stereo and mono 
>diffential output for the LINE output (that has no notable effect), 
>but not for the Headphone output.

Never mind; This happens if you plug a CTIA headset into a OMTP jack.

Michael