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";
+		io-width = <32>;
+	};
+
 	memory@80000000 {
 		device_type = "memory";
 		reg = <0x0 0x80000000 0x1 0x0>;

-- 
2.43.0

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.

> +		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.

> +
>  	memory@80000000 {
>  		device_type = "memory";
>  		reg = <0x0 0x80000000 0x1 0x0>;
> 
> -- 
> 2.43.0
> 

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

On Tue, Jul 15, 2025 at 10:32:09AM +0200, Clement LE GOFFIC wrote:
> 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 ?

Oh wait, we already have a binding for that. I was confused with your 
adding "jedec,ddr4-channel". Sorry for the noise.

Rob

Hi Rob

On 7/15/25 17:02, Rob Herring wrote:
> On Tue, Jul 15, 2025 at 10:32:09AM +0200, Clement LE GOFFIC wrote:
>> 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 ?
> 
> Oh wait, we already have a binding for that. I was confused with your
> adding "jedec,ddr4-channel". Sorry for the noise.

It's fine no worries.
However, in the patch 8, I add the property "memory-channel" that is not 
in the dtschema repo and I didn't get any reviews on it.
Is it ok for you ? or maybe should we discuss it over there ?
I can try to do a PR on the dtschema thought, if it is ok.

Best regards,
Clément