Re: [alsa-devel] [PATCH] ASoC: da7219: check SRM lock in trigger callback

From: Pierre-Louis Bossart
Date: Wed Feb 12 2020 - 11:03:56 EST



Thanks Ranjani. That information closes the door on the idea of playing
with the trigger order suggested earlier in the thread, so my guess is
that we really need to expose the MCLK/BCLK with the clk API and turn
them on/off from the machine driver as needed. I hope is that we don't
need the FSYNC as well, that would be rather painful to implement.

Am not going to make myself popular here. It's MCLK and FSYNC (or WCLK as it's
termed for our device) that is required for SRM to lock in the PLL.

So far I've not found a way in the codec driver to be able to get around this.
I spent a very long time with Sathya in the early days (Apollo Lake) looking at
options but nothing would fit which is why I have the solution that's in place
right now. We could probably reduce the number of rechecks before timeout in the
driver but that's really just papering over the crack and there's still the
possibility of noise later when SRM finally does lock.

Sorry, you lost me at "the solution that's in place right now". There is nothing in the bxt_da7219_max98357a.c code that deals with clocks or defines a trigger order?