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Subject: Re: [PATCH v2 1/2] dt-bindings: dwc2: Add bindings for new Ingenic
 SoCs.
From:   "H. Nikolaus Schaller" <hns@goldelico.com>
In-Reply-To: <40d34f8b-4ab7-5ced-b533-da1f4b501cdc@wanyeetech.com>
Date:   Thu, 14 Apr 2022 19:18:00 +0200
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        hminas@synopsys.com, Rob Herring <robh+dt@kernel.org>,
        linux-usb@vger.kernel.org, linux-mips <linux-mips@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS 
        <devicetree@vger.kernel.org>, dragancecavac@yahoo.com,
        dongsheng.qiu@ingenic.com, qipengzhen <aric.pzqi@ingenic.com>,
        rick.tyliu@ingenic.com, sernia.zhou@foxmail.com,
        zhenwenjin@gmail.com, reimu@sudomaker.com
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References: <1649788201-87620-1-git-send-email-zhouyanjie@wanyeetech.com>
 <1649788201-87620-2-git-send-email-zhouyanjie@wanyeetech.com>
 <6F03670F-9040-4560-AD78-CC7A03EC678F@goldelico.com>
 <c79a8ff7-7a3f-9627-f910-dbbf942e34cb@wanyeetech.com>
 <0AE74BF9-46F1-44EC-8E5F-40EA12851AD0@goldelico.com>
 <76ea346b-0645-97b5-f8fb-5b46b4bcc80b@linaro.org>
 <F6929BAA-D552-4C34-B392-33AEA263F0C9@goldelico.com>
 <40d34f8b-4ab7-5ced-b533-da1f4b501cdc@wanyeetech.com>
To:     Zhou Yanjie <zhouyanjie@wanyeetech.com>
Precedence: bulk

Hi,

> Am 14.04.2022 um 19:11 schrieb Zhou Yanjie =
<zhouyanjie@wanyeetech.com>:
>=20
> Hi,
>=20
> On 2022/4/14 =E4=B8=8B=E5=8D=886:00, H. Nikolaus Schaller wrote:
>>=20
>>> Am 14.04.2022 um 09:32 schrieb Krzysztof Kozlowski =
<krzysztof.kozlowski@linaro.org>:
>>>=20
>>> On 13/04/2022 21:30, H. Nikolaus Schaller wrote:
>>>> So we need "snps,dwc2" to get any driver match and I thought the =
"ingenic,jz4780-otg" is redundant.
>>>>=20
>>>> But maintainers convinced me to keep it as a dummy compatible in =
the .dtsi for potential future
>>>> specialization (which does not exist and seems not to be =
necessary).
>>> Isn't exactly the next patch 2/2 using such specialization?
>>>=20
>>>> Unless I can convince them
>>>> that this is never ever needed. Which is beyond my knowledge and =
almost everyone.
>>>>=20
>>>> So we can't remove the "snps,dwc2" here.
>>>>=20
>>>> Well, we can with more work elsewhere.
>>>> You have to extend the dwc2_of_match_table to include all ingenic =
devices.
>>>>=20
>>>> Therefore we now know 3 potential solutions:
>>>> a) remove "ingenic,jz4780-otg" from jz4780.dtsi (my proposal)
>>>> b) add "ingenic,jz4780-otg" to dwc2.yaml together with "snps,dwc2" =
(your proposal + my suggestion here)
>>>> c) add only "ingenic,jz4780-otg" to dwc2.yaml and extend the match =
table in drivers//usb/dwc2/params.c (new proposals)
>>>>=20
>>>> =46rom consistency point of view I think variant b) is the right =
one. a) was rejected and c) only adds redundant code.
>>> c) was already proposed by Zhou, so if you think the code is not =
correct
>>> (the params for jz4780) maybe nack it there, so we will know that =
driver
>>> needs fixes.
>> Ah, ok. Now I see. I was just focussed on this patch and related =
dtbscheck
>> messages and did not read patch 2/2.
>>=20
>> Yes, looking at both, they are variant c). Sorry that I didn't see it =
earlier.
>=20
> It looks like we need a [3/3] to remove "snps,dwc2", which not only =
solves
> the dtbscheck complaining problem, but also doesn't affect normal use =
after
> removing "snps,dwc2".

Yes, that seems to be the right thing to do.

BR and thanks,
Nikolaus