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From:   Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     broonie@kernel.org, lgirdwood@gmail.com, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org,
        kuninori.morimoto.gx@renesas.com, perex@perex.cz, tiwai@suse.com,
        alsa-devel@alsa-project.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 2/2] dt-bindings: ASoC: simple-card: Add
 system-clock-id property
In-reply-to: <874e74ae-86bb-7950-1615-36e1a326e177@linaro.org>
Date:   Wed, 26 Oct 2022 20:27:07 +0100
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Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> writes:

> On 26/10/2022 10:48, Aidan MacDonald wrote:
>>
>> Krzysztof Kozlowski <krzysztof.kozlowski@linaro.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 :)

No problem, thanks for bearing with all my explanations! Mark raised
some good points, and I have to agree with him. This could create too
many future issues, and the problem might be better solved with the
clock API -- but unfortunately that's not yet feasible.

Regards,
Aidan