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Date:   Sun, 17 Sep 2023 09:35:17 +0200
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Subject: Re: [PATCH v2 8/8] arm64: defconfig: enable interconnect and pinctrl
 for SM4450
To:     Georgi Djakov <djakov@kernel.org>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Tengfei Fan <quic_tengfan@quicinc.com>, will@kernel.org,
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From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <c11fd3c2-770a-4d40-8cf3-d8bc81f7c480@kernel.org>
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On 17/09/2023 00:55, Georgi Djakov wrote:
> Hi Krzysztof,
> 
> On 16.09.23 23:32, Krzysztof Kozlowski wrote:
>> On 16/09/2023 17:13, Georgi Djakov wrote:
>>>
>>>>
>>>> Complete list here, and it is inconsistent. Latest 8550 is also =y. Do we document
>>>> the reasons somewhere on why they are added as =y?
>>>>
>>>> CONFIG_INTERCONNECT_QCOM=y
>>>> CONFIG_INTERCONNECT_QCOM_MSM8916=m
>>>> CONFIG_INTERCONNECT_QCOM_MSM8996=m
>>>> CONFIG_INTERCONNECT_QCOM_OSM_L3=m
>>>> CONFIG_INTERCONNECT_QCOM_QCM2290=m
>>>> CONFIG_INTERCONNECT_QCOM_QCS404=m
>>>> CONFIG_INTERCONNECT_QCOM_SA8775P=y
>>>> CONFIG_INTERCONNECT_QCOM_SC7180=y
>>>> CONFIG_INTERCONNECT_QCOM_SC7280=y
>>>> CONFIG_INTERCONNECT_QCOM_SC8180X=y
>>>> CONFIG_INTERCONNECT_QCOM_SC8280XP=y
>>>> CONFIG_INTERCONNECT_QCOM_SDM845=y
>>>> CONFIG_INTERCONNECT_QCOM_SM8150=m
>>>> CONFIG_INTERCONNECT_QCOM_SM8250=m
>>>> CONFIG_INTERCONNECT_QCOM_SM8350=m
>>>> CONFIG_INTERCONNECT_QCOM_SM8450=y
>>>> CONFIG_INTERCONNECT_QCOM_SM8550=y
>>>
>>> If the device can boot (to console/initramfs) with =m, we go with that.
>>> But if something critical like the UART depends on the interconnect
>>> provider, then we make it built-in.
>>>
>>> On SM8550 for example, we have enabled bandwidth scaling support for QUP
>>> and that's why it needs to be =y.
>>>
>>> It looks like on SM4450 this should be =y too.
>>
>> I asked why SM4450 has to be =y and there was no answer. The argument
>> that SM8450 is a module, is not applicable.
> 
>  From the hardware description i see in patch 7, the serial engine depends
> on some interconnect provider. But as the serial console driver is only
> available as built-in, the interconnect provider also needs be built-in
> for the UART device to probe and register the console.
> 
> So the answer to your question should be that this is needed by the UART
> device (at least).
> 
> Such details of course deserve to be mentioned in the commit message of
> this patch.

If you mean here the debug UART with console, then it is the same valid
reason as in my change for others. This should be mentioned in commit msg.

Best regards,
Krzysztof