Message-ID: <89588f69-9cf0-e7a4-b976-5ce87d42e296@arinc9.com>
Date:   Thu, 2 Mar 2023 13:22:19 +0300
From:   Arınç ÜNAL <arinc.unal@...nc9.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Rob Herring <robh@...nel.org>
Cc:     Sergio Paracuellos <sergio.paracuellos@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-mediatek@...ts.infradead.org, linux-mips@...r.kernel.org,
        linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Matthias Brugger <matthias.bgg@...il.com>,
        Sean Wang <sean.wang@...nel.org>,
        William Dean <williamsukatube@...il.com>,
        Daniel Golle <daniel@...rotopia.org>,
        Daniel Santos <daniel.santos@...ox.com>,
        Luiz Angelo Daros de Luca <luizluca@...il.com>,
        Frank Wunderlich <frank-w@...lic-files.de>,
        Landen Chao <Landen.Chao@...iatek.com>,
        DENG Qingfang <dqfext@...il.com>,
        Sean Wang <sean.wang@...iatek.com>, erkin.bozoglu@...ont.com
Subject: Re: [RFC PATCH 07/16] dt-bindings: pinctrl: ralink: add new
 compatible strings

On 2.03.2023 12:58, Krzysztof Kozlowski wrote:
> On 02/03/2023 10:17, Arınç ÜNAL wrote:
>> On 2.03.2023 11:28, Krzysztof Kozlowski wrote:
>>> On 01/03/2023 09:15, Arınç ÜNAL wrote:
>>>> On 1.03.2023 05:44, Rob Herring wrote:
>>>>> On Tue, Feb 28, 2023 at 07:46:36PM +0300, Arınç ÜNAL wrote:
>>>>>> On 27/02/2023 20:33, Rob Herring wrote:
>>>>>>> On Wed, Feb 22, 2023 at 09:39:23PM +0300, arinc9.unal@...il.com wrote:
>>>>>>>> From: Arınç ÜNAL <arinc.unal@...nc9.com>
>>>>>>>>
>>>>>>>> Add the ralink,rt2880-pinmux compatible string. It had been removed from
>>>>>>>> the driver which broke the ABI.
>>>>>>>>
>>>>>>>> Add the mediatek compatible strings. Change the compatible string on the
>>>>>>>> examples with the mediatek compatible strings.
>>>>>>>>
>>>>>>>> Signed-off-by: Arınç ÜNAL <arinc.unal@...nc9.com>
>>>>>>>> ---
>>>>>>>>      .../devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml | 7 +++++--
>>>>>>>>      .../devicetree/bindings/pinctrl/ralink,mt7621-pinctrl.yaml | 7 +++++--
>>>>>>>>      .../devicetree/bindings/pinctrl/ralink,rt2880-pinctrl.yaml | 7 +++++--
>>>>>>>>      .../devicetree/bindings/pinctrl/ralink,rt305x-pinctrl.yaml | 7 +++++--
>>>>>>>>      .../devicetree/bindings/pinctrl/ralink,rt3883-pinctrl.yaml | 7 +++++--
>>>>>>>>      5 files changed, 25 insertions(+), 10 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
>>>>>>>> index 1e63ea34146a..531b5f616c3d 100644
>>>>>>>> --- a/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
>>>>>>>> +++ b/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
>>>>>>>> @@ -17,7 +17,10 @@ description:
>>>>>>>>      properties:
>>>>>>>>        compatible:
>>>>>>>> -    const: ralink,mt7620-pinctrl
>>>>>>>> +    enum:
>>>>>>>> +      - mediatek,mt7620-pinctrl
>>>>>>>> +      - ralink,mt7620-pinctrl
>>>>>>>
>>>>>>> We don't update compatible strings based on acquistions nor marketing
>>>>>>> whims. If you want to use 'mediatek' for new things, then fine.
>>>>>>
>>>>>> Understood. Only the SoCs with rtXXXX were rebranded, the mtXXXX SoCs share
>>>>>> the same architecture from Ralink, so they were incorrectly called Ralink
>>>>>> SoCs.
>>>>>>
>>>>>> I can remove the new strings from Ralink SoCs and add them only for MediaTek
>>>>>> SoCs. Or you could make an exception for this one, regarding the situation.
>>>>>> Whatever you think is best.
>>>>>
>>>>> I'm not in a position to make an exception as I know little about this
>>>>> platform. Carrying both strings is a NAK. Either you (and everyone using
>>>>> these platforms) care about the ABI and are stuck with the "wrong"
>>>>> string. In the end, they are just unique identifiers. Or you don't care
>>>>> and break the ABI and rename everything. If you do that, do just that in
>>>>> your patches and make it crystal clear in the commit msg that is your
>>>>> intention and why that is okay.
>>>>
>>>> Ralink had their MIPS SoCs pre-acquisition, RT2880, etc. MediaTek
>>>> introduced new SoCs post-acquisition, MT7620, MT7621, MT7628, and
>>>> MT7688, utilising the same platform from Ralink, sharing the same
>>>> architecture code, pinctrl core driver, etc.
>>>>
>>>> I don't intend to break the ABI at all. On the contrary, I fix it where
>>>> possible.
>>>>
>>>> If I understand correctly, from this conversation and what Krzysztof
>>>> said, all strings must be kept on the schemas so I can do what I said on
>>>> the composed mail. Only match the pin muxing information on the strings
>>>> that won't match multiple pin muxing information from other schemas.
>>>>
>>>> This way we don't break the ABI, introduce new compatible strings while
>>>> keeping the remaining ones, and make schemas match correctly.
>>>>
>>>> Let me know if this is acceptable to you.
>>>
>>> If by "introduce new compatible strings" you mean duplicate compatibles
>>> to fix the ralink->mediatek, then you ignored entire email from Rob -
>>> this and previous. We don't do this. Leave them as is.
>>>
>>> If you meant something else, explain more...
>>
>> Let me put them in a group to better explain.
>>
>> ## Fix ABI
>>
>> ralink,rt2880-pinmux was there before, it was removed which broke the
>> ABI. I'm reintroducing it to fix it.
>>
>> ## New strings to be able to split bindings
>>
>> New strings are needed for MT7628/MT7688 and some RT SoCs to be able to
>> properly document the pin muxing information.
> 
> Then ok.
> 
>>
>> ## 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?

> 
>>
>> ## Exception for RT SoCs to be called MediaTek
>>
>> This is where I was asking an exception to be made. Rob told us here
>> they know little about the platform so I explained it.
>>
>> MediaTek acquired Ralink and then introduced new MediaTek SoCs utilising
>> the same platform from Ralink.
>>
>> Anyway, now that I look at this again, it makes sense to me as well not
>> to rename the Ralink SoCs. I'll call the RT SoCs Ralink on the kconfig,
>> pinctrl driver,
> 
> These are separate. We did not comment on how you call Linux drivers.
> The mail thread was only about:
> 
>> and dt-binding schemas on my next version.

Understood, thanks.

Arınç

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