Message-ID: <19f46c69-fbfc-4129-98ae-fc5aef3f75eb@oss.qualcomm.com>
Date: Mon, 29 Dec 2025 18:19:25 +0800
From: Tingwei Zhang <tingwei.zhang@....qualcomm.com>
To: Krzysztof Kozlowski <krzk@...nel.org>,
        YijieYang <yijie.yang@....qualcomm.com>
Cc: andersson@...nel.org, konradybcio@...nel.org, robh@...nel.org,
        krzk+dt@...nel.org, conor+dt@...nel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH 3/4] arm64: dts: qcom: Commonize IQ-X-IOT DTSI



On 12/29/2025 3:21 PM, Krzysztof Kozlowski wrote:
> On 29/12/2025 02:23, Tingwei Zhang wrote:
>>
>> On 12/24/2025 8:12 AM, Tingwei Zhang wrote:
>>> On 12/23/2025 9:41 PM, Krzysztof Kozlowski wrote:
>>>> On 23/12/2025 04:38, Tingwei Zhang wrote:
>>>>> On 12/22/2025 5:11 PM, Krzysztof Kozlowski wrote:
>>>>>> On Mon, Dec 22, 2025 at 02:03:28PM +0800, YijieYang wrote:
>>>>>>> From: Yijie Yang <yijie.yang@....qualcomm.com>
>>>>>>>
>>>>>>> HAMOA-IOT-EVK and PURWA-IOT-EVK share a similar board design. Extract
>>>>>>> the common components into separate files for better maintainability.
>>>>>> SoMs do not share actual hardware. DTSI does not represent what looks
>>>>>> similar to you, but actually common parts.
>>>>> Purwa SOM board and Hamoa SOM board share same design. They share same PCB.
>>>>> The difference is only on chip. Purwa SOM board has Purwa and Hamoa SOM board
>>>>> has Hamoa on it. 
>>>> I do not speak about boards. Read carefully feedback and respond to the
>>>> actual feedback, not some other arguments.
>>>>
>>>> NAK
>>> In this change, the SoM hardware except SoC is described by iq-x-iot-som.dtsi since it's common between Hamoa and Purwa. Hamoa and Purwa SoC hardware is described in hamoa.dtsi and purwa.dtsi. Hamoa-iot-som.dtsi includes iq-x-iot-som.dtsi and hamoa.dtsi. This change could reduce the duplicate code and review effort on a totally new purwa-iot-som.dtsi. If we found any bug, it can be fixed in one common file instead of two separate files. Same idea is used in x1-crd.dtsi. X1e80100-crd.dts include x1-crd.dtsi and hamoa.dtsi.
>> Krzysztof,
>> Please let me know your opinion on this. This could be a common case for
>> Hamoa/Purwa boards share same PCB. Share same dtsi file like x1-crd.dtsi
> It's not the same PCB.  You did not really respond to my first message,
> so I responded to you - I do not speak about boards. Then again you did
> not respond to it and brought some irrelevant arguments.
>
>> would reduce maintenance effort.
> Does not matter, I do not question this. Why are you responding to some
> questions which were never asked?
>
> DTSI represents actual shared physical aspect and you cannot share SoM
> physically. It's not the same PCB, because you do not have a socket on
> the SoM.
I didn't make myself clear enough. The SOM PCB I referred here is just the circuit
board excluding the components on it.  Let me rephrase.

Hamoa and Purwa SOM boards have very similar hardware design. They share
same circuit board and most the components on it. The only difference is Hamoa
SOM board has Hamoa SoC while Purwa SOM board has Purwa SoC.

I agree they are not same PCB since the SoCs are different. 

However, I still think it's better to use common dtsi iq-x-iot-som.dtsi since their
hardware design is very similar. 

I'll invite Konrad to chime in here as author of x1-crd.dtsi and Qualcomm SoC
maintainer. I think we are facing similar case on purwa evk and purwa crd.
Align to same strategy for device tree topology would be good.

> Best regards,
> Krzysztof

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