linux-kernel - Re: [PATCH v1 2/2] dt-bindings: ASoC: simple-card: Add system-clock-id property

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Date:   Wed, 26 Oct 2022 11:03:19 -0400
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Aidan MacDonald <aidanmacdonald.0x0@...il.com>
Cc:     broonie@...nel.org, lgirdwood@...il.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org,
        kuninori.morimoto.gx@...esas.com, perex@...ex.cz, tiwai@...e.com,
        alsa-devel@...a-project.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/2] dt-bindings: ASoC: simple-card: Add
 system-clock-id property

On 26/10/2022 10:48, Aidan MacDonald wrote:
> 
> Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> writes:
> 
>> And the remaining piece I don't get is that these are not bindings for
>> codec, but for sound audio card. You want to set "system-clock-id"
>> property for audio card, while putting clock from codec, which will be
>> used to pass back to the codec... so it is a property of the codec, not
>> of the audio card. IOW, NAU8821_CLK_* does not configure here the clock
>> of the system, but only, only clock of the codec.
> 
> The system clock is controlled at the DAI level, it's specific to one
> DAI on one component. The simple-card device node has sub-nodes for the
> DAI links, and each DAI link node has sub-nodes for the DAIs within the
> link. "system-clock-id" is a property on the DAI nodes, so it's not a
> card-level property, just one part of the overall card definition.
> 
> Since the clock ID is something defined by the codec it would naturally
> be a value defined by the codec, but the *configuration* of the codec is
> part of the sound card because it depends on how everything is connected
> together. If you used the same codec in a different machine it would
> have a different configuration.


OK, that sounds reasonable. Thank you for explaining this. You still
need to convince Mark :)

Best regards,
Krzysztof