Unable to attach an LED to headphones without HW mute ALSA Control

[GitHub issues - opened <github@alsa-project.org>]

alsa-project/alsa-ucm-conf issue #527 was opened from stefdb:

I have a laptop with a CS42L43 Codec which supplies the Headphone Jack.
I'm trying to attach the mute state of the Headphones to the Speaker LED.

However, the issue is that the CS42L43 does not possess a Hardware Mute ALSA Control which could be attached to the Speaker LED.

I first tried to use the Volume Control to attach to the LED, however, that was a non-starter because the Mute is software controlled, and thus muting headphones did not touch the Volume Control.

I then tried to add a new control using cset-new, and link it to the Headphones device ([0001-sof-soundwire-Attach-cs42l43-Headphone-Switch-to-spe.patch](https://github.com/user-attachments/files/19321741/0001-sof-soundwire-Attach-cs42l43-Headphone-Switch-to-spe.patch)), and whilst that worked with the LED, the mute no longer actually muted the Headphone, since there was now a "real" control to set the mute which did not actually mute the Device.

Other things I have tried include mapping the Volume control as a Switch, but that does not work, I assume, because the switch control needs to be Boolean.

Is there a way to create a new control to track the LED status, whilst also ensuring that the Headphones still mute?

Issue URL     : https://github.com/alsa-project/alsa-ucm-conf/issues/527
Repository URL: https://github.com/alsa-project/alsa-ucm-conf