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Subject: Re: [PATCH v1 1/3] dt-bindings: mmc: Drop unused properties
From:   Jessica Clarke <jrtc27@jrtc27.com>
In-Reply-To: <20230901-affected-wanting-ab517791a870@spud>
Date:   Fri, 1 Sep 2023 19:39:14 +0100
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>
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References: <20230830031846.127957-1-william.qiu@starfivetech.com>
 <20230830031846.127957-2-william.qiu@starfivetech.com>
 <20230830-commence-trickery-40eaa193cb15@wendy>
 <b375b88c-0d9c-30a9-21f6-283083cf3880@linaro.org>
 <20230830-procedure-frostbite-56c751f7c276@wendy>
 <efab6f52-4d7f-ea3c-0fc3-4e3ad03c14c7@starfivetech.com>
 <20230901-remold-sublease-a1ddb1fc6348@spud>
 <9EF26965-10E5-4BCA-AC5E-93C5AA55A0DF@jrtc27.com>
 <20230901-affected-wanting-ab517791a870@spud>
To:     Conor Dooley <conor@kernel.org>
Precedence: bulk

On 1 Sep 2023, at 18:43, Conor Dooley <conor@kernel.org> wrote:
>=20
> On Fri, Sep 01, 2023 at 06:20:38PM +0100, Jessica Clarke wrote:
>> On 1 Sep 2023, at 16:42, Conor Dooley <conor@kernel.org> wrote:
>>>=20
>>> On Fri, Sep 01, 2023 at 10:33:13AM +0800, William Qiu wrote:
>>>>=20
>>>>=20
>>>> 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.
>>>>>>>=20
>>>>>>> How does changing your software implantation invalidate a =
description of
>>>>>>> the hardware?
>>>>>>>=20
>>>>>>=20
>>>>>> 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.
>>>>>=20
>>>>> :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.
>>>>>=20
>>>>>> 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.
>>>>>=20
>>>>> I'm not sure if laziness is fair, lack of understanding is usually =
more
>>>>> likely.
>>>>=20
>>>> 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.
>>>=20
>>> Please only remove it from required if the current driver doesn't =
break
>>> if the regmap is removed.
>>=20
>> Either way please make sure the documentation clearly states =E2=80=9Cn=
ever use
>> this, if you=E2=80=99re using it you=E2=80=99re doing it wrong, this =
only exists
>> because it was wrongly used in the past=E2=80=9D. Otherwise people =
writing
>> drivers for other OSes will probably use it too thinking they need =
to.
>=20
> Maybe we should just delete it if the impact is going to be =
negligible,
> sounds like you're not using it in FreeBSD, which was part of what I =
was
> worried about. Guess it depends on what Emil & the distro heads think.

FreeBSD doesn=E2=80=99t have StarFive drivers yet; I don=E2=80=99t have =
time to write
them, and a community member has taken it upon themselves as a hobby
but is rather inexperienced and has been struggling for months. OpenBSD
has drivers, including a modified dwmmc, but doesn=E2=80=99t use this =
property
(in fact its driver doesn=E2=80=99t use the compatible other than to =
probe the
generic driver). I don=E2=80=99t think anyone else has a serious port; =
Haiku=E2=80=99s
the closest but also has no StarFive support.

Jess