Re: [PATCH v2 3/8] dt-bindings: marvell: a38x: add solidrun armada 388 clearfog boards

From: Josua Mayer <josua@solid-run.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Gregory Clement <gregory.clement@bootlin.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>
Subject: Re: [PATCH v2 3/8] dt-bindings: marvell: a38x: add solidrun armada 388 clearfog boards
Date: Sun, 24 Dec 2023 16:29:35 +0000	[thread overview]
Message-ID: <28729f48-1357-4f3a-bd7b-e9c34bcf2c58@solid-run.com> (raw)
In-Reply-To: <0be16ab8-8be4-4af4-af0b-4287beeb0386@linaro.org>

Am 24.12.23 um 17:09 schrieb Krzysztof Kozlowski:
> On 24/12/2023 17:02, Josua Mayer wrote:
>> Am 24.12.23 um 15:55 schrieb Krzysztof Kozlowski:
>>> On 24/12/2023 15:38, Josua Mayer wrote:
>>>> Add DT compatible for SolidRun Armada-388 based Clearfog Base and Pro
>>>> boards.
>>>>
>>>> While they are just two variants, we have 3 device-tree:
>>>> - armada-388-clearfog.dts
>>>> - armada-388-clearfog-base.dts
>>>> - armada-388-clearfog-pro.dts
>>>>
>>>> While the first one is identical to the pro variant, the filename is
>>>> not, and neither are the compatible strings.
>>>>
>>>> The first is compatible to armada-380, 385, 388 and
>>>> solidrun,clearfog-a1.
>>>> The other two are compatible to the same, plus an additional string
>>>> including the pro/base as suffix.
>>>>
>>>> Add two bindings, one for the explicit pro and base variants using a
>>>> total of 5 compatibles, and one for the generic name using just 4.
>>>>
>>>> Signed-off-by: Josua Mayer <josua@solid-run.com>
>>>> ---
>>>>    .../bindings/arm/marvell/armada-38x.yaml      | 20 +++++++++++++++++++
>>>>    1 file changed, 20 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/arm/marvell/armada-38x.yaml b/Documentation/devicetree/bindings/arm/marvell/armada-38x.yaml
>>>> index 5bc69c4fe34d..25c29b466094 100644
>>>> --- a/Documentation/devicetree/bindings/arm/marvell/armada-38x.yaml
>>>> +++ b/Documentation/devicetree/bindings/arm/marvell/armada-38x.yaml
>>>> @@ -38,4 +38,24 @@ properties:
>>>>              - const: marvell,armada385
>>>>              - const: marvell,armada380
>>>>    
>>>> +      - description: |
>>>> +          SolidRun Armada 388 SoM based clearfog board. This is
>>>> +          equivalent to clearfog pro, but lacks the "pro" label
>>>> +          in dtb filename and compatible strings.
>>>> +        items:
>>>> +          - const: solidrun,clearfog-a1
>>> SoM cannot be alone.
>> Please confirm, I think my wording above was not clear.
>>
>> I meant to say "clearfog" devices based on a SoM,.
>> Armada 388 Clearfog Base / Pro are combinations of SoM and carrier.
>> Current device-trees do not mention a som-specific compatible string though.
> So Clearfog Base is a board, then what is Clearfog A1?
"Clearfog A1" is printed on the silk screen of a Clearfog Pro revision 
2.0 or earlier.
I don't have a later revision to look at.
So Clearfog A1 and Clearfog Pro  and Clearfog Pro A1 all mean the same 
board,
Clearfog Base (+-A1) mean the other board.

"-a1" of the compatible string is already used by openwrt to differentiate.

>
>> This is in contrast to "Clearfog GTR" which
>> a) uses aramda-385
>> b) solders SoC to the board.
>>
>>>> +          - const: marvell,armada388
>>>> +          - const: marvell,armada385
>>>> +          - const: marvell,armada380
>>>> +
>>>> +      - description: SolidRun Armada 388 SoM based clearfog board variants
>>>> +        items:
>>>> +          - enum:
>>>> +             - solidrun,clearfog-base-a1
>>> Board has name "base"?
>> Yes.
>> In marketing and in device-tree model field the board names are
>> Clearfog Base, Clearfog Pro
> Then clearfog-base or clearfog-a1-base, but why a1 is at the end? Or is
> it the case that Clearfog Base can have different SoMs? Think what you
> have there and choose appropriate compatibles. See Renesas SMARC for one
> choice and iMX Toradex boards for different example
Conceptually at this point, is it worth changing the compatibles of 
existing boards to make sense?
Or better to describe them in yaml as they are now (ensuring language is 
understood)?

If I try really hard, I can add a new armada-388 som compatible, but 
that opens another can.
There are other boards also based on the solidrun armada-388 SoMs, e.g. 
helios4 - and
there is no shared -som dtsi.
Effectively I guess they are all just individual boards, maybe not worth 
mentioning "SoM".

>
> Best regards,
> Krzysztof
>

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