linux-kernel - Re: [PATCH v3 1/1] arm64: dts: qcom: sm8550: remove address/size-cells from mdss

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Message-ID: <ad1547cf-0520-422d-a105-ec426f526d71@quicinc.com>
Date: Wed, 20 Dec 2023 08:53:48 +0800
From: "Aiqun Yu (Maria)" <quic_aiquny@...cinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
CC: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Tengfei Fan
	<quic_tengfan@...cinc.com>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <conor+dt@...nel.org>,
        <linux-arm-msm@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <kernel@...cinc.com>
Subject: Re: [PATCH v3 1/1] arm64: dts: qcom: sm8550: remove
 address/size-cells from mdss_dsi1



On 12/19/2023 6:21 PM, Dmitry Baryshkov wrote:
> On Tue, 19 Dec 2023 at 12:09, Aiqun Yu (Maria) <quic_aiquny@...cinc.com> wrote:
>>
>>
>>
>> On 12/19/2023 5:41 PM, Krzysztof Kozlowski wrote:
>>> On 19/12/2023 10:36, Aiqun Yu (Maria) wrote:
>>>>
>>>>
>>>> On 12/19/2023 3:17 PM, Krzysztof Kozlowski wrote:
>>>>> On 19/12/2023 01:31, Tengfei Fan wrote:
>>>>>> The address/size-cells in mdss_dsi1 node have not ranges and child also
>>>>>> have not reg, then this leads to dtc W=1 warnings:
>>>>>
>>>> Comments can be more readable:
>>>> "mdss_dsi1" node don't have "ranges" or child "reg" property, while it
>>>> have address/size-cells properties. This caused
>>>> "avoid_unnecessary_addr_size" warning from dtb check.
>>>> Remove address/size-cells properties for "mdss_dsi1" node.
>>>>
>>>>> I cannot parse it. Address/size cells never have ranges or children.
>>>>> They cannot have. These are uint32 properties.
>>>> Pls help to comment on the revised commit message. Every time I write a
>>>> commit message, also takes a while for me to double confirm whether
>>>> others can understand me correctly as well. Feel free to let us know if
>>>> it is not readable to you. It will help us as non-English native developers.
>>>>>
>>>>>>
>>>>>>      sm8550.dtsi:2937.27-2992.6: Warning (avoid_unnecessary_addr_size): /soc@...isplay-subsystem@...0000/dsi@...6000:
>>>>>>        unnecessary #address-cells/#size-cells without "ranges" or child "reg" property
>>>>>>
>>>>>>
>>>>>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
>>>>>> Signed-off-by: Tengfei Fan <quic_tengfan@...cinc.com>
>>>>>> ---
>>>>>
>>>>> I disagreed with the patch before. You resubmit it without really
>>>>> addressing my concerns.
>>>>>
>>>>> I am not sure if this is correct fix and I want to fix all of such
>>>>> errors (there are multiple of them) in the same way. Feel free to
>>>>> propose common solution based on arguments.
>>>> Per my understanding, "qcom,mdss-dsi-ctrl" driver node like "mdss_dsi1"
>>>> don't need to have address/size-cells properties.
>>>
>>> Just because dtc says so? And what about bindings?
>> I don't find any reason why "qcom,mdss-dsi-ctrl" driver node need to
>> have address/size-cells properties. Document Bindings should also be fixed.
>>>
>>>> Feel free to let us know whether there is different idea of
>>>> "address/size-cells" needed for the "qcom,mdss-dsi-ctrl" driver node.
>>>
>>> The bindings expressed that idea. If the binding is incorrect, fix the
>>> binding and the DTS. If the binding is correct, provide rationale why it
>>> somehow does not apply here etc.
>> Our plan is to fix the bindings as well.
>>
>> In case you have missed the question, I just re-place it here:
>> While there are about 22 different soc dtsi and it's document binding
>> files needed to be fixed. Shall we fix it for all qcom related soc usage
>> in one patch, or we'd better to split into different patches according
>> to soc specifically?
> 
> Don't touch the bindings unless you understand what you are doing.
> Your patch will be NAKed. There can be a DSI panel attached to the DSI
> host, which means there is a need for #address-cells / #size-cells.
> 
Could you please help to elaborate more on details? Like what's the 
right example here for the "qcom,mdss-dsi-ctrl" driver node needed to 
have "#address-cells"/"#size-cells".

Thx to chime in that we have put a good amount of time here.
> Please stop wasting the time on dtc warning. The bindings (and the
> file) are correct.
I don't agree here.
Either it is a wrong usage of "#address-cells"/"#size-cells", or dtc 
warning should be fixed with this usage take into account.
"dtb check" will be a good guideline for developers to follow, I don't 
think it is wasting time here.
> 

-- 
Thx and BRs,
Aiqun(Maria) Yu