Re: [PATCH 1/2] dt-bindings: arm64: dts: mediatek: Add mt8395-evk board

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On 9/5/23 18:58, AngeloGioacchino Del Regno and Krzsztof Kozlowski wrote:
Il 05/09/23 12:36, Krzysztof Kozlowski ha scritto:
On 05/09/2023 11:36, Macpaul Lin wrote:


On 9/4/23 20:11, Krzysztof Kozlowski wrote:


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On 04/09/2023 11:50, Macpaul Lin wrote:


On 9/4/23 17:33, Krzysztof Kozlowski wrote:


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On 04/09/2023 11:20, Macpaul Lin wrote:
Add bindings for the MediaTek mt8395-evk board.
The mt8359-evk board is also named as "Genio 1200-EVK".
MT8195 and MT8395 are the same family series SoC could share

How can be the same and have different numbers? You sill need dedicated
compatible.


The SoCs mt8195 and mt8395 are designed for different market application
and physical characteristics, using different efuse values for
distinction. The booting flow and configurations are controllered by the
boot loaders, firmware, and TF-A. Therefore, the part numbers and
procurement channels are different. The detail information of these
efuse values is proprietary, so I cant disclose it futher. Hence the
most of peripheral drivers and base address are almost the same.

1. Drivers? So we talk about compatibility, not the same.
2. "almost the same" is not the same. Follow the guidelines for writing
bindings.


Thanks for the review.

After internal confirmation and discussion, it can be confirmed that the
MT8195 and MT8395 are identical SoCs from to binding's perspective.

I am sorry, but I really do not care what you internally discussed about
bindings. I do not think your internal review respect existing
guidelines. You talked about drivers, not "bindings perspective", so
your internal discussion is clearly discussing something else.

MediaTek hope the mt8395 boards could directly use mt8195.dtsi, without
the need to create a separate mt8395.dtsi to include mt8195.dtsi.
Therefore, we hope to fully adopt the bindings of mt8195. However, I
will submit a revised patch for compatible since they are different boards.

You can disagree but then I expect arguments from your side.


In short - they're the same chip, as in, they behave the same on a *hardware* perspective; what changes is the bootchain (plus stricter security from TF-A)
and allowable temperature ranges for operation, that's practically it...

...so yes the compatible for the "new soc" must be documented, but that's
practically just a revision, *not a new soc* at all.

(though, I agree that seeing a different name as in 1 -> 3 can be totally
confusing)

The drivers difference that Macpaul hinted to are about drivers needing some SMC calls instead of direct MMIO manipulation, so, something like two bindings for something like two drivers will need to add a 8395 compatible; speaking of what we would have in a devicetree for this SoC, that'd be exactly 99% identical
to mt8195.dtsi.

Anyway, drivers are drivers, bindings describe hardware - and the hw is, again,
the same...

Hope that this makes things clearer! :-)

Cheers,
Angelo

Thanks for your patience and clarification.
I'll submit new SOC binding and revise the patches for mt8395 board.

Thanks
Macpaul Lin



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