Re: [PATCH v2 06/16] arm64: dts: st: add LPDDR channel to stm32mp257f-dk board

[Clement LE GOFFIC <clement.legoffic@foss.st.com>]

Hi Rob,

Thanks for the review !

On 7/15/25 05:20, Rob Herring wrote:
> On Fri, Jul 11, 2025 at 04:48:58PM +0200, Clément Le Goffic wrote:
>> Add 32bits LPDDR4 channel to the stm32mp257f-dk board.
>>
>> Signed-off-by: Clément Le Goffic <clement.legoffic@foss.st.com>
>> ---
>>   arch/arm64/boot/dts/st/stm32mp257f-dk.dts | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/arch/arm64/boot/dts/st/stm32mp257f-dk.dts b/arch/arm64/boot/dts/st/stm32mp257f-dk.dts
>> index a278a1e3ce03..a97b41f14ecc 100644
>> --- a/arch/arm64/boot/dts/st/stm32mp257f-dk.dts
>> +++ b/arch/arm64/boot/dts/st/stm32mp257f-dk.dts
>> @@ -54,6 +54,13 @@ led-blue {
>>   		};
>>   	};
>>   
>> +	lpddr_channel: lpddr4-channel {
>> +		#address-cells = <1>;
>> +		#size-cells = <0>;
>> +		compatible = "jedec,lpddr4-channel";
> 
> Not tested because this doesn't match the binding.

Hmm, I've tested with make dtbs_check and dt_binding_check and it didn't 
complain on my side.
What I have miss ?


> 
>> +		io-width = <32>;
>> +	};
> 
> What would multiple channels look like? I think this needs some work.
> Like it should perhaps be within the memory node. It's a lot to just say
> 32-bit LPDDR4 x1.

I guess something like two channels node following each other in the DT.
It can be in the memory node I don't know what are the stakes here.
I was inspired by the lpddr node here:
arch/arm/boot/dts/samsung/exynos5422-odroid-core.dtsi:336

Best regard,
Clément