Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <676dae73-9b59-d0bb-37ca-eaa120e8dcb5@linaro.org>
Date:   Tue, 2 May 2023 21:27:15 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.10.1
Subject: Re: [PATCH v4 2/2] dt-bindings: usb: snps,dwc3: Add the compatible
 name 'snps,dwc3-rtk-soc'
Content-Language: en-US
To:     =?UTF-8?B?U3RhbmxleSBDaGFuZ1vmmIzogrLlvrdd?= 
        <stanley_chang@realtek.com>,
        Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Felipe Balbi <balbi@kernel.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <20230502050452.27276-1-stanley_chang@realtek.com>
 <20230502050452.27276-2-stanley_chang@realtek.com>
 <2653e0d1-6570-7469-51da-b539b5c14299@linaro.org>
 <bc5cd630d96f44bcaad7f95f2f45aac1@realtek.com>
 <49d2b103-de1e-637a-1bf0-aaba1c6afaf4@linaro.org>
 <a04e70f97bcb48048edb2f6db7bb6c25@realtek.com>
 <f51b4dc9-e1da-7c9c-1e39-c8510569db9d@linaro.org>
 <c44baa9fae5c445c90103cd2e129ab0b@realtek.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <c44baa9fae5c445c90103cd2e129ab0b@realtek.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 02/05/2023 12:37, Stanley Chang[昌育德] wrote:
> Hi Krzysztof,
> 
>>>>>> On 02/05/2023 07:04, Stanley Chang wrote:
>>>>>>> Add a new compatible name 'snps,dwc3-rtk-soc' of DT for realtek
>>>>>>> dwc3 core to adjust the global register start address
>>>>>>>
>>>>>>> The RTK DHC SoCs were designed, the global register address offset
>>>>>>> at
>>>>>>
>>>>>> What are: "RTK" and "DHC"? These are manufactured by Synopsys as
>>>>>> you suggest in the patch?
>>>>>
>>>>> RTK is Realtek.
>>>>> DHC is the department name in Realtek and the abbreviation of the
>>>>> Digital
>>>> Home Center.
>>>>> The USB controller of RTK DHC SoCs used the DWC3 IP of Synopsys.
>>>>
>>>> Then entire compatible is not correct. Vendor is Realtek not Synopsys.
>>>> DHC is not even device name. Use real device names.
>>>
>>> So, can we use the compatible name as 'realtek,dwc3' ?
>>
>> dwc3 is not a real device name for Realtek.
> 
> We still use dwc3 IP in Realtek's SoC. Why is the name "dwc3" inappropriate?

dwc3 is the name of design coming from Synopsys. Your device is probably
called differently. Why it is inappropriate? Because your device is not
called DWC3, even though you use IP from Synopsys.

Although vendor,dwc3 is already used as compatible in several cases, I
don't think it is a good pattern.

> 
> Should compatibility names use the SoC name?
> For example, our SoC name
> RTD129x, RTD139x, RTD161x, RTD161xB, etc.
> Should we use these names in compatible names?
> "realtek, rtd129x", "realtek, rtd139x", "realtek, rtd161x"...etc.

Regular rules apply, because your device is not special.
https://elixir.bootlin.com/linux/v6.1-rc1/source/Documentation/devicetree/bindings/writing-bindings.rst#L42

Therefore either SoC-based device specific name or followed by:
1. SoC-based device specific fallback,
2. Family-device generic fallback,


Best regards,
Krzysztof