Message-ID: <a696bea5-3ba6-3b71-10ad-a04a7412c178@linaro.org>
Date:   Fri, 3 Mar 2023 08:05:40 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.8.0
Subject: Re: [RFC PATCH 07/16] dt-bindings: pinctrl: ralink: add new
 compatible strings
Content-Language: en-US
To:     =?UTF-8?B?QXLEsW7DpyDDnE5BTA==?= <arinc.unal@arinc9.com>,
        Rob Herring <robh@kernel.org>
Cc:     Sergio Paracuellos <sergio.paracuellos@gmail.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        linux-mediatek@lists.infradead.org, linux-mips@vger.kernel.org,
        linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Sean Wang <sean.wang@kernel.org>,
        William Dean <williamsukatube@gmail.com>,
        Daniel Golle <daniel@makrotopia.org>,
        Daniel Santos <daniel.santos@pobox.com>,
        Luiz Angelo Daros de Luca <luizluca@gmail.com>,
        Frank Wunderlich <frank-w@public-files.de>,
        Landen Chao <Landen.Chao@mediatek.com>,
        DENG Qingfang <dqfext@gmail.com>,
        Sean Wang <sean.wang@mediatek.com>, erkin.bozoglu@xeront.com
References: <20230222183932.33267-1-arinc.unal@arinc9.com>
 <20230222183932.33267-8-arinc.unal@arinc9.com>
 <20230227173333.GA496999-robh@kernel.org>
 <d7aea90f-d077-3a41-996c-804c95d72e24@arinc9.com>
 <20230301024431.GA251215-robh@kernel.org>
 <ae3346de-140f-f181-b6a3-ccaa694e1548@arinc9.com>
 <11d3c806-04b6-da54-65f1-c0bd154affbc@linaro.org>
 <a9acd3b4-2b03-86c0-711c-a3840aeab574@arinc9.com>
 <1aae7ac9-c83d-71b4-4fce-325f02fcd722@linaro.org>
 <89588f69-9cf0-e7a4-b976-5ce87d42e296@arinc9.com>
 <2ccb573d-39f4-cb80-7a3e-63a60c2bc0a8@linaro.org>
 <b48e0a5e-dd45-8b8a-4ee3-357a0985ca9c@arinc9.com>
 <83a03258-9e52-3d09-67fe-12e9e5ed4b76@linaro.org>
 <11d10e4e-65ec-3bec-3e0c-7e57feb03506@arinc9.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <11d10e4e-65ec-3bec-3e0c-7e57feb03506@arinc9.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 02/03/2023 12:50, Arınç ÜNAL wrote:
> On 2.03.2023 14:36, Krzysztof Kozlowski wrote:
>> On 02/03/2023 11:47, Arınç ÜNAL wrote:
>>> On 2.03.2023 13:29, Krzysztof Kozlowski wrote:
>>>> On 02/03/2023 11:22, Arınç ÜNAL wrote:
>>>>>>>
>>>>>>> ## Incorrect naming
>>>>>>>
>>>>>>> MT7620, MT7621, MT7628, and MT7688 SoCs are incorrectly called Ralink,
>>>>>>> introduce new ralink->mediatek compatible strings to address it.
>>>>>>
>>>>>> So this part was addressed by Rob - we don't do it, because it does not
>>>>>> matter. Ralink is now Mediatek, thus there is no conflict and no issues
>>>>>> with different vendor used.
>>>>>
>>>>> I think Rob was rather addressing that updating compatible strings based
>>>>> on acquisition or marketing whims is not permitted. This condition does
>>>>> not apply here as these SoCs were never Ralink.
>>>>>
>>>>> I understand your point that Ralink is now MediaTek but still, calling
>>>>> these SoCs Ralink would be a bit misleading, don't you think?
>>>>
>>>> Misleading yes, but also does not matter. At least matter not enough to
>>>> justify ABI break, so you would need to deprecate old ones and keep
>>>> everything backwards compatible. You still would affect 3rd party users
>>>> of DTS, though...
>>>
>>> I intend to do just that. Introduce new mediatek strings, keep the old
>>> ones so it's backwards compatible, therefore don't break the ABI.
>>>
>>> Instead of deprecating old strings, I intend to introduce the checks I
>>> mentioned, on the schema, so the pin muxing bindings only apply if the
>>> DT has got a string that won't match multiple schemas. This way it
>>> shouldn't affect 3rd party DTs.
>>
>> I meant, 3rd party users of DTS. You will replace the compatible in the
>> DTS, right? So the DTS exported and used in all other projects, OS,
>> firmwares, bootloaders, out of tree kernel forks will stop working.
> 
> I plan to change it on the DTs for MediaTek SoCs, yes. Is this a 
> problem? From what I can tell, what must be ensured is that old DTs must 
> work with newer kernels, not new DTs on older kernels.

Can I be clearer than this?

" So the DTS exported and used in all other projects, OS,
firmwares, bootloaders, out of tree kernel forks will stop working."

Yes, this is a problem - they will stop working.

Best regards,
Krzysztof