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

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Message-ID: <043c8384-6ce2-c78e-f52c-6a37a4bab3a0@linux.intel.com>
Date:   Wed, 12 Feb 2020 09:48:24 -0600
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Adam Thomson <Adam.Thomson.Opensource@...semi.com>,
        "Sridharan, Ranjani" <ranjani.sridharan@...el.com>
Cc:     "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        Support Opensource <Support.Opensource@...semi.com>,
        Takashi Iwai <tiwai@...e.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Chiang, Mac" <mac.chiang@...el.com>,
        Mark Brown <broonie@...nel.org>,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        "Lu, Brent" <brent.lu@...el.com>,
        "cychiang@...gle.com" <cychiang@...gle.com>
Subject: Re: [alsa-devel] [PATCH] ASoC: da7219: check SRM lock in trigger
 callback


>> 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?