linux-kernel - Re: [PATCH v3 2/9] dt-bindings: display: add verisilicon,dc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0b7ba974-d8d5-4417-8182-3e9299315058@kernel.org>
Date: Wed, 26 Nov 2025 11:22:45 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Icenowy Zheng <uwu@...nowy.me>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Drew Fustini <fustini@...nel.org>,
 Guo Ren <guoren@...nel.org>, Fu Wei <wefu@...hat.com>,
 Philipp Zabel <p.zabel@...gutronix.de>, Heiko Stuebner <heiko@...ech.de>,
 Andrzej Hajda <andrzej.hajda@...el.com>,
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
 Michal Wilczynski <m.wilczynski@...sung.com>
Cc: Han Gao <rabenda.cn@...il.com>, Yao Zi <ziyao@...root.org>,
 dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v3 2/9] dt-bindings: display: add verisilicon,dc

On 26/11/2025 10:50, Icenowy Zheng wrote:
>>> +maintainers:
>>> +  - Icenowy Zheng <uwu@...nowy.me>
>>> +
>>> +properties:
>>> +  $nodename:
>>> +    pattern: "^display@[0-9a-f]+$"
>>> +
>>> +  compatible:
>>> +    items:
>>> +      - enum:
>>> +          - thead,th1520-dc8200
>>> +      - const: verisilicon,dc
>>
>> I do not see any explanation of exception for generic compatibles,
>> maybe
>> except "self-identification" remark. Rob already pointed this out, so
>> be
>> explicit in commit msg why you are using a generic compatible.
> 
> Well I only get the meaning of "a SoC specific compatible is required"
> in his review message.
> 
> I think my binding now requires both a SoC-specific compatible and a
> generic compatible, which should be okay to satisfy Rob's original
> review.

You will get then the same questions for me - what justifies generic
compatible. You should be on this explicit, because otherwise people
misinterpret some commits and patches, and they think the generic
compatible is allowed for them as well.

> 
>>
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  interrupts:
>>> +    maxItems: 1
>>> +
>>> +  clocks:
>>> +    minItems: 4
>>
>> This is not flexible. Device either has or has not these clocks.
> 
> The existence of all these clocks are verified by diagrams in manuals

So not flexible, then:

> of two different SoCs with DC8200 (T-Head TH1520 and StarFive JH7110).
> 
> Maybe a explicit `maxItems: 5` is needed here, but as my DT passes
> dtbs_check, I don't think it's necessary?

No, drop minItems only.

> 
> Or maybe I should drop the flexibility now and use a `minItems: 5` here
> (and leave DC8000 support as another story)? (The Eswin EIC7700 manual
> does not have a diagram showing external connections of the DC, like
> the two SoCs I mentioned above).

You document here only the devices explicitly mentioned in the binding.
You cannot add here constraints or clocks for some device which is not
in the binding and I see only th1520 in the binding.

Best regards,
Krzysztof