Re: [PATCH 2/4] dt-bindings: media: Add bindings for raspberrypi,rp1-cfe

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Naushir Patuck <naush@raspberrypi.com>,
	Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Jacopo Mondi <jacopo.mondi@ideasonboard.com>,
	Kieran Bingham <kieran.bingham@ideasonboard.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Raspberry Pi Kernel Maintenance <kernel-list@raspberrypi.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Florian Fainelli <florian.fainelli@broadcom.com>,
	Broadcom internal kernel review list
	<bcm-kernel-feedback-list@broadcom.com>
Subject: Re: [PATCH 2/4] dt-bindings: media: Add bindings for raspberrypi,rp1-cfe
Date: Wed, 20 Mar 2024 10:12:05 +0100	[thread overview]
Message-ID: <38aaf71a-511d-4e63-9014-07f591d8250b@linaro.org> (raw)
In-Reply-To: <CAEmqJPoBA4PrbvoGHtiah1B=C7WO+MODUUY0qr0ZdF2eWEB3TA@mail.gmail.com>

On 20/03/2024 09:50, Naushir Patuck wrote:
>>>>
>>>> Also, I'm still wondering about the RP1 part there in the compatible
>>>> string. Is it necessary? The CFE is located in the RP1 co-processor, but
>>>> is that relevant?
>>>>
>>>> Is there a versioning for the whole RP1 chip? Maybe it's going to the
>>>> wrong direction if we use the board/SoC for this compatible name, as
>>>> it's actually the RP1 where the CFE is located in, not the SoC.
>>>>
>>>
>>> I don't really know the conversion required to answer this one.
>>> Logically CFE is on RP1, so it makes sense to me to have "rp1" in the
>>> string, but I will follow the judgment of the maintainers.
>>
>> Well, my thinking here was that if we have a register from which to read
>> the version, and Raspberry Pi would create a new co-processor, RP2, with
>> the same CFE. Would we then have "raspberrypi,rp1-cfe" and
>> "raspberrypi,rp2-cfe", even if there are no changes? 

That would follow guidelines as expressed in writing bindings.

>>Or would a plain
>> "raspberrypi,cfe" do for both?
>>
>> In other words, if we don't need the "rp1" for versioning purposes,
>> should it then be dropped?
> 
> I agree with the above, you've convinced me that "raspberrypi,cfe"
> might be the more appropriate string, or a convincing argument for
> that to be a fallback string.

Just follow the guidelines. If you come up with generic compatible
alone, you could run to the same problems everyone is running.

Best regards,
Krzysztof

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