Message-ID: <8cac29c3-6b05-479d-a06b-583f9def7beb@oss.qualcomm.com>
Date: Mon, 29 Dec 2025 12:27:38 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Tingwei Zhang <tingwei.zhang@....qualcomm.com>,
        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 12/29/25 11:19 AM, Tingwei Zhang wrote:
> 
> 
> 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.

Hamoa CRD vs Purwa CRD are literally a just a SoC swapped PCB as far as
I'm aware

Konrad

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