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Date:   Tue, 9 Aug 2022 11:47:44 +0300
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Subject: Re: [PATCH 1/3] dt-bindings: sound: Add Apple MCA I2S transceiver
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To:     =?UTF-8?Q?Martin_Povi=c5=a1er?= <povik+lin@cutebit.org>
Cc:     Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Philipp Zabel <p.zabel@pengutronix.de>, asahi@lists.linux.dev,
        alsa-devel@alsa-project.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
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From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
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On 09/08/2022 11:40, Martin Povišer wrote:
>> Describe the items because otherwise you allow any order. The list will
>> be unfortunately quite long, but still readable enough.
> 
> Well, I would assume the ‘dmas’ property as described above has an implicit
> natural order, and the dma-names are tied to it. You order it like the other
> per-cluster properties, and then within the cluster the order is fixed to
> 'TXA, RXA, TXB, RXB’ (maybe the word ‘respectively’ thrown into the description
> would have made it clearer).
> 
> Anyway that’s just discussing my assumptions. I can roll out the items list
> for ‘dma-names’, if that’s what you mean. Or do you mean explicitly describing
> the items in ‘dmas’ too?

The text description of 'dmas' does not mean it will be followed by DTS
author. In current bindings DTS author can therefore put any order of
dmas/dma-names. Unrolling the dma-names forces this order to be fixed
and validated by dtschema.

> 
>>> +    description: |
>>> +      Names for the DMA channels: 'tx'/'rx', then cluster number, then 'a'/'b'
>>> +      based on the associated SERDES unit.
>>> +
> 
> (...)
> 
>>> +
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> +  - |
>>> +    mca: mca@9b600000 {
>>
>> You called it I2S transceiver but isn't it also actually I2S controller?
>> If yes, then the node name should be probably "i2s".
> 
> It’s a peripheral you use to transmit and receive samples over I2S, frankly
> I don't know the nomenclature.

Looking at other devices, it's i2s.

Best regards,
Krzysztof