Just recently installed my HifiBerry DAC+ ADC Pro on a RPi 4 with the latest LibreELEC/KODI. I added "dtoverlay=hifiberry-dacplusadcpro" to the appropriate place in config.txt and it seems to work just fine for a number of hours, then the audio will cut out. Get it back, I shut it down, unplug and restart everything... and then after a few hours it happens again.
dmesg shows this several times in a row:
[ 3891.059025] pcm512x 1-004d: No SCLK, using BCLK: -2
But that doesn't seem to cause the audio drop, but then this one does appear to coincide with the dropped audio:
[20017.198742] pcm512x 1-004d: Failed to set digital mute: -121