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Date:   Wed, 5 Jul 2023 21:56:11 +0200
From:   Andreas Kemnade <andreas@kemnade.info>
To:     Mark Brown <broonie@kernel.org>
Cc:     bcousson@baylibre.com, tony@atomide.com, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
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        peter.ujfalusi@gmail.com, jarkko.nikula@bitmer.com,
        dmitry.torokhov@gmail.com, linux-omap@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        alsa-devel@alsa-project.org
Subject: Re: [PATCH 2/3] ASoC: tlv320aic3x: use BCLK instead of MCLK if not
 in master mode
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In-Reply-To: <15d3fc6e-d294-4968-bc7d-66307efc92db@sirena.org.uk>
References: <20230705190324.355282-1-andreas@kemnade.info>
        <20230705190324.355282-3-andreas@kemnade.info>
        <15d3fc6e-d294-4968-bc7d-66307efc92db@sirena.org.uk>
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On Wed, 5 Jul 2023 20:21:58 +0100
Mark Brown <broonie@kernel.org> wrote:

> On Wed, Jul 05, 2023 at 09:03:23PM +0200, Andreas Kemnade wrote:
> 
> > +	/* probably no mclk if not master, so rely on bitclk */
> > +	if (!aic3x->master)
> > +		clk_id = 2;
> > +  
> 
> This is fairly clearly a massive hack, we're just silently ignoring the
> clock we were asked to configure and choosing another one which is
> likely at a different rate to that we were expecting and sadly the
> driver didn't provide an automatic mode due to how old it is.  We also
> appear to try to use the configured clock rate during PLL setup which
> still happens in hw_params() even with this change which is a bit of a
> concern here.  Are you sure hw_params ends up doing the right thing, and
> that there are no other systems that get broken by this (perhaps ones
> sending a lower BCLK for example)?

Yes, I am not that happy myself with that one. Possible victim is
keystone-k2g-evm.dts. 
I looked for if (master) things and found the pll enable/disable connected to it.
But that is not the whole story...
> 
> It would be nicer to set the clock via the DT bindings, ideally with the
> clock bindings...

I found no path from these simple-audio-card things to provide a clk_id 
to set_dai_sysclk. I would of course prefer such a thing. Do I have overlooked
something?

Regards,
Andreas