linux-kernel - Re: [PATCH 1/4] ASoC: dt-bindings: document new symmetric-clock-role flag

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Date:   Tue, 6 Jun 2023 15:39:59 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Alvin Šipraga <ALSI@...g-olufsen.dk>
Cc:     Alvin Šipraga <alvin@...s.dk>,
        Liam Girdwood <lgirdwood@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/4] ASoC: dt-bindings: document new symmetric-clock-role
 flag

On Fri, Jun 02, 2023 at 12:42:49PM +0000, Alvin Šipraga wrote:

> Yes I see what you mean. On my platform the clock source is actually described
> by the common clock framework, so I would want to use that. If it were a
> component driver then it would most likely be a codec that is part of the
> dai-link anyway. So what about having two struct clk pointers in struct
> snd_soc_dai?
> 
>     struct snd_soc_dai {
>         /* ... */
>         struct clk *bitclock_provider;
>         struct clk *frameclock_provider;
>         /* ... */
>     };

> If non-NULL I could then have the ASoC core enable/disable the clocks on demand?
> I would say in hw_params/hw_free, albeit that runs after set_fmt.

hw_params() can be called repeatedly so that's not a good fit but
broadly yes.

> Having said that, I see ASoC doesn't really use the CCF much... am I way off?

Ideally we'd be representing more of the clocking via the clock
framework but at present yes.

> I don't think it's feasible to modify every component driver to explicitly
> handle this and then ignore any CBP_CFP bits set in its call to set_fmt - this
> is why I want help from the ASoC core.

Sure, but that's not going to impact the DT bindings.  All these things
are driven from the machine driver.

> > If simple-card can't be made to work that's fine, it's deprecated
> > anyway.

> Ah OK, I didn't know that. Right now I'm using graph-card2, that's not
> deprecated, right?

Yes, audio-graph-card replaces simple-card.

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