Re: [PATCH v1 1/3] dt-bindings: mmc: Drop unused properties

From: Jessica Clarke <jrtc27@jrtc27.com>
To: Conor Dooley <conor@kernel.org>
Cc: William Qiu <william.qiu@starfivetech.com>,
	Conor Dooley <conor.dooley@microchip.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	linux-mmc@vger.kernel.org, Emil Renner Berthing <kernel@esmil.dk>,
	Rob Herring <robh+dt@kernel.org>,
	Jaehoon Chung <jh80.chung@samsung.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>
Subject: Re: [PATCH v1 1/3] dt-bindings: mmc: Drop unused properties
Date: Fri, 1 Sep 2023 18:20:38 +0100	[thread overview]
Message-ID: <9EF26965-10E5-4BCA-AC5E-93C5AA55A0DF@jrtc27.com> (raw)
In-Reply-To: <20230901-remold-sublease-a1ddb1fc6348@spud>

On 1 Sep 2023, at 16:42, Conor Dooley <conor@kernel.org> wrote:
> 
> On Fri, Sep 01, 2023 at 10:33:13AM +0800, William Qiu wrote:
>> 
>> 
>> On 2023/8/30 16:34, Conor Dooley wrote:
>>> On Wed, Aug 30, 2023 at 09:29:20AM +0200, Krzysztof Kozlowski wrote:
>>>> On 30/08/2023 08:50, Conor Dooley wrote:
>>>>> On Wed, Aug 30, 2023 at 11:18:44AM +0800, William Qiu wrote:
>>>>>> Due to the change of tuning implementation, it's no longer necessary to
>>>>>> use the "starfive,sysreg" property in dts, so drop the relevant
>>>>>> description in dt-bindings here.
>>>>> 
>>>>> How does changing your software implantation invalidate a description of
>>>>> the hardware?
>>>>> 
>>>> 
>>>> Which is kind of proof that this syscon was just to substitute
>>>> incomplete hardware description (e.g. missing clocks and phys). We
>>>> should have rejected it. Just like we should reject them in the future.
>>> 
>>> :s I dunno what to do with this... I'm inclined to say not to remove it
>>> from the binding or dts at all & only change the software.
>>> 
>>>> There are just few cases where syscon is reasonable. All others is just
>>>> laziness. It's not only starfivetech, of course. Several other
>>>> contributors do the same.
>>> 
>>> I'm not sure if laziness is fair, lack of understanding is usually more
>>> likely.
>> 
>> For this, I tend to keep it in binding, but remove it from required. Because
>> we only modify the tuning implementation, it doesn't mean that this property
>> need to be removed, it's just no longer be the required one.
> 
> Please only remove it from required if the current driver doesn't break
> if the regmap is removed.

Either way please make sure the documentation clearly states “never use
this, if you’re using it you’re doing it wrong, this only exists
because it was wrongly used in the past”. Otherwise people writing
drivers for other OSes will probably use it too thinking they need to.

Jess

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