On 16/08/2022 12:25, Jernej Škrabec wrote:

Dne torek, 16. avgust 2022 ob 11:12:05 CEST je Heiko Stübner napisal(a):

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Am Dienstag, 16. August 2022, 09:49:58 CEST schrieb Jernej Škrabec:

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Dne torek, 16. avgust 2022 ob 09:41:45 CEST je Krzysztof Kozlowski 

napisal(a):

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On 15/08/2022 08:08, Samuel Holland wrote:

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+
+	de: display-engine {
+		compatible = "allwinner,sun20i-d1-display-engine";
+		allwinner,pipelines = <&mixer0>, <&mixer1>;
+		status = "disabled";
+	};
+
+	osc24M: osc24M-clk {

lowercase

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+		compatible = "fixed-clock";
+		clock-frequency = <24000000>;

This is a property of the board, not SoC.

SoC needs 24 MHz oscillator for correct operation, so each and every board
has it. Having it here simplifies board DT files.

I guess the oscillator is a separate component on each board, right?

Correct.

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And DT obvious is meant to describe the hardware - independently from
implementation-specific choices.

There is no choice in this case. 24 MHz crystal has to be present.

FWIW, including crystal node in SoC specific DTSI is already common pattern in 
Allwinner ARM SoC DTSI files.

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Starting to discuss which exceptions to allow then might lead to even more
exceptions.

Also having to look for a board-component in the soc dtsi also is surprising
if one gets to the party later on :-) .

As I said, if one is accustomed to Allwinner ARM DT development, it would be 
more surprising to include 24 MHz crystal node in each and every board DT.

It's same everywhere. Allwinner, Exynos, iMX, Qualcomm. Everywhere this
is a part of the board, so even if oscillator frequency is fixed (as in
99% of cases although some SoCs I think might just allow to implement
one of few), still this is a property of the board. Because:
1. DTSI describes the SoC part, not board.
2. So the DTS developer is a bit more conscious about his design.

Keeping things in SoC DTSI just because it simplifies DTS is not correct
IMHO. So again - like in several other cases - minimum the frequency is
property of the board, not the SoC DTSI.

Everywhere. Allwinner is not special to receive exceptions.

Best regards,
Krzysztof