Re: [RFC PATCH 1/3] dt-bindings: arm64: bcmbca: Merge BCM4908 into BCMBCA

From: William Zhang <william.zhang@broadcom.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	Linux ARM List <linux-arm-kernel@lists.infradead.org>
Cc: kursad.oney@broadcom.com, anand.gore@broadcom.com,
	dan.beygelman@broadcom.com, f.fainelli@gmail.com,
	Broadcom Kernel List <bcm-kernel-feedback-list@broadcom.com>,
	joel.peshkin@broadcom.com,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	rafal@milecki.pl
Subject: Re: [RFC PATCH 1/3] dt-bindings: arm64: bcmbca: Merge BCM4908 into BCMBCA
Date: Tue, 12 Jul 2022 17:57:32 -0700	[thread overview]
Message-ID: <6efb1cfe-6129-276a-eeb3-44147304d211@broadcom.com> (raw)
In-Reply-To: <c40f20c7-59ee-99f4-9a11-e928b41eda9f@linaro.org>

[-- Attachment #1.1: Type: text/plain, Size: 2027 bytes --]

On 7/12/22 11:18, Krzysztof Kozlowski wrote:
> On 12/07/2022 19:37, William Zhang wrote:
>>>> +      - description: BCM4908 Family based boards
>>>> +        items:
>>>> +          - enum:
>>>> +              # BCM4908 SoC based boards
>>>> +              - brcm,bcm94908
>>>> +              - asus,gt-ac5300
>>>> +              - netgear,raxe500
>>>> +              # BCM4906 SoC based boards
>>>> +              - brcm,bcm94906
>>>> +              - netgear,r8000p
>>>> +              - tplink,archer-c2300-v1
>>>> +          - enum:
>>>> +              - brcm,bcm4908
>>>> +              - brcm,bcm4906
>>>> +              - brcm,bcm49408
>>>
>>> This is wrong.  brcm,bcm94908 followed by brcm,bcm4906 does not look
>>> like valid list of compatibles.
>>>
>> For 4908 board variant, it will need to be followed by 4908 chip. Sorry
>> for the basic question but is there any requirement to enforce this kind
>> of rule?  I would assume dts writer know what he/she is doing and select
>> the right combination.
> 
> The entire point of DT schema is to validate DTS. Combination like above
> prevents that goal.
> 
> Best regards,
> Krzysztof
Understand the DT schema purpose. But items property allows multiple 
enums in the list which gives a lot of flexibility but make it hard to 
validate. I am not familiar with DT schema, is there any directive to 
specify one enum value depending on another so dts validation tool can 
report error if combination is wrong?

This is our preferred format of all bcmbca compatible string especially 
when we could have more than 10 chip variants for the same chip family 
and we really want to work on the chip family id.  We will make sure 
they are in the right combination in our own patch and patch from other 
contributors. Would this work? If not, I will probably have to revert 
the change of 4908(maybe append brcm,bcmbca as this chip belongs to the 
same bca group) and use "enum board variant", "const main chip id", 
"brcm,bca" for all other chips as our secondary choice.

[-- Attachment #1.2: S/MIME Cryptographic Signature --]
[-- Type: application/pkcs7-signature, Size: 4212 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel