Re: [PATCH 12/13] ARM: dts: stm32: fix DSI port node on STM32MP15

From: Alexandre TORGUE <alexandre.torgue@foss.st.com>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>, <arnd@arndb.de>,
	<robh+dt@kernel.org>, Marek Vasut <marex@denx.de>,
	<jagan@amarulasolutions.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Marcin Sloniewski <marcin.sloniewski@gmail.com>
Cc: <linux-arm-kernel@lists.infradead.org>,
	<devicetree@vger.kernel.org>,
	<linux-stm32@st-md-mailman.stormreply.com>,
	<linux-kernel@vger.kernel.org>, Lee Jones <lee.jones@linaro.org>,
	<kuba@kernel.org>
Subject: Re: [PATCH 12/13] ARM: dts: stm32: fix DSI port node on STM32MP15
Date: Thu, 15 Apr 2021 14:23:32 +0200	[thread overview]
Message-ID: <96da49dc-f24d-aa12-e1d8-39b5a5b6fbc9@foss.st.com> (raw)
In-Reply-To: <ececc78c-4fca-bb93-ef62-5d107501d963@pengutronix.de>

Hi Ahmad

On 4/15/21 12:43 PM, Ahmad Fatoum wrote:
> Hi,
> 
> On 15.04.21 12:10, Alexandre Torgue wrote:
>> Running "make dtbs_check W=1", some warnings are reported concerning
>> DSI. This patch reorder DSI nodes to avoid:
>>
>> soc/dsi@5a000000: unnecessary #address-cells/#size-cells without
>> "ranges" or child "reg" property
> 
> This reverts parts of commit 9c32f980d9 ("ARM: dts: stm32: preset
> stm32mp15x video #address- and #size-cells"):
>      
>      The cell count for address and size is defined by the binding and not
>      something a board would change. Avoid each board adding this
>      boilerplate by having the cell size specification in the SoC DTSI.
>      
> 
> The DSI can have child nodes with a unit address (e.g. a panel) and ones
> without (ports { } container). ports is described in the dtsi, panels are
> described in the dts if available.
> 
> Apparently, the checker is fine with
> ports {
> 	#address-cells = <1>;
> 	#size-cells = <0>;
> };
> 
> I think my rationale for the patch above was sound, so I think the checker
> taking offense at the DSI cells here should be considered a false positive.

If it's a "false positive" warning then we need to find a way to not 
print it out. Else, it'll be difficult to distinguish which warnings are 
"normal" and which are not. This question could also be applied to patch[3].

Arnd, Rob what is your feeling about this case ?

thanks
alex

> Thanks,
> Ahmad
> 
>>
>> Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
>>
>> diff --git a/arch/arm/boot/dts/stm32mp157.dtsi b/arch/arm/boot/dts/stm32mp157.dtsi
>> index 54e73ccea446..c355fcf26ec3 100644
>> --- a/arch/arm/boot/dts/stm32mp157.dtsi
>> +++ b/arch/arm/boot/dts/stm32mp157.dtsi
>> @@ -24,8 +24,6 @@
>>   			clock-names = "pclk", "ref", "px_clk";
>>   			resets = <&rcc DSI_R>;
>>   			reset-names = "apb";
>> -			#address-cells = <1>;
>> -			#size-cells = <0>;
>>   			status = "disabled";
>>   
>>   			ports {
>> diff --git a/arch/arm/boot/dts/stm32mp157c-dk2.dts b/arch/arm/boot/dts/stm32mp157c-dk2.dts
>> index 19ef475a48fc..763dde1dbbaf 100644
>> --- a/arch/arm/boot/dts/stm32mp157c-dk2.dts
>> +++ b/arch/arm/boot/dts/stm32mp157c-dk2.dts
>> @@ -36,6 +36,8 @@
>>   &dsi {
>>   	status = "okay";
>>   	phy-dsi-supply = <&reg18>;
>> +	#address-cells = <1>;
>> +	#size-cells = <0>;
>>   
>>   	ports {
>>   		port@0 {
>> diff --git a/arch/arm/boot/dts/stm32mp157c-ev1.dts b/arch/arm/boot/dts/stm32mp157c-ev1.dts
>> index 6fe5b0fee7c4..4625bb58cc6d 100644
>> --- a/arch/arm/boot/dts/stm32mp157c-ev1.dts
>> +++ b/arch/arm/boot/dts/stm32mp157c-ev1.dts
>> @@ -102,6 +102,8 @@
>>   &dsi {
>>   	phy-dsi-supply = <&reg18>;
>>   	status = "okay";
>> +	#address-cells = <1>;
>> +	#size-cells = <0>;
>>   
>>   	ports {
>>   		port@0 {
>>
> 