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

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Message-ID: <CAA8EJpo07gE7ZeNP6wSGTLtmF_3PKQAKFyMRZ8dk1K+f7PAxrg@mail.gmail.com>
Date: Tue, 19 Dec 2023 12:21:23 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: "Aiqun Yu (Maria)" <quic_aiquny@...cinc.com>
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 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.

Please stop wasting the time on dtc warning. The bindings (and the
file) are correct.

-- 
With best wishes
Dmitry