RE: 回复: [PATCH v2 1/2] ASoC: dt-bindings: Add bindings for Cadence I2S-MC controller

29 Mar 2024

      On 27/03/2024 13:12, Krzysztof Kozlowski wrote:
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On 26/03/2024 14:43, Xingyu Wu wrote:
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+properties:

compatible:
enum:
 - cdns,i2s-mc

Why did this appear? Who asked for this? Usually these blocks are
not usable on their own.
I wonder if I should keep the original IP compatible. Do I not need it?
As I said, it is not usable on its own, so unless you have other arguments then
no.
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But my point was that no one asked for this.
I want to keep the original IP compatible which can distinguish from the JH8100
SoC.
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Can I write it like this:
compatible:
   enum:
          - starfive,jh8100-i2s
   const: cdns,i2s-mc
and I write this in the DTS:
compatible = "starfive,jh8100-i2s", "cdns,i2s-mc";
Can you provide any rationale for this? I asked "unless you have other
arguments", so where are the arguments?
Nothing was explained in patch changelog. Nothing was provided in this email
thread.
I don't know if I understood what mark said[1]. Is it to keep the original IP and
add other compatible?
[1] https://lore.kernel.org/all/27155281-573c-493d-96fe-1f28ebb0ce5e@sirena.org....
Or should I only keep the compatible 'starfive,jh8110-i2s' and change the
bindings name to same to this compatible?
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 - starfive,jh8100-i2s

reg:
maxItems: 1

interrupts:
description:
 The interrupt line number for the I2S controller. Add this

 parameter if the I2S controller that you are using does not

 using DMA.

That's still wrong. You already got comment on this. Either you
have interrupt
or not.
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You do not add interrupts, based on your choice or not of having DMA.
Drop the comment.
Do I keep this property and drop this description?
Drop description. Keep property, if your hardware has interrupts.
Will drop.
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compatible

reg

clocks

clock-names

resets

+oneOf:

required:

 - dmas

 - dma-names

required:

 - interrupts

This won't work. Provide both interrupts and dmas, and then test your DTS.
I provided both properties in the DTS and test by dtbs_check. Then
it printed
that:
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'More than one condition true in one of shema: ...'
Exactly. Having both properties is a correct DTS. Interrupts do not
disappear just because you decide to describe DMA. It is OS choice
what to use if both are provided.
But this I2S can only use either DMA or interrupts.
Just like many other components. DTS should reflect hardware. Hardware has
interrupts and DMA, right?
Yes. The hardware can use interrupts and provide the handshake interface of
DMA to DMA controller. In software, we can choose only one between them.
Do I keep them both in the bindings and provide the selection in the driver?
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Can I use the config (like SND_SOC_CADENCE_I2S_MC_PCM)  to choose DMA
or interrupt if having both them in DTS?
Don't know, I tend to focus here on bindings.
Best regards,
Xingyu Wu