Per this topic NoDebugFS I cannot force the aud_mclk on using sysfs.
I can turn it on with a dummy gstreamer pipeline
gst-launch-1.0 -e alsasrc device=hw:1,2 ! fakesink
That is less reliable than forcing on the clock via the sysfs.
I was thinking of creating a modified version of the alsa+gst driver that sets the clock on and leaves it; but finding the relevant code has proved to be difficult.
Can anybody provide a pointer to the relevant code?