Re: [PATCH] arm64: dts: exynos850: Add SRAM node

[Alexey Klimov]

On Wed May 6, 2026 at 1:11 PM BST, Tudor Ambarus wrote:
>
>
> On 4/30/26 6:37 PM, Alexey Klimov wrote:
>> On Tue Apr 14, 2026 at 10:08 AM BST, Krzysztof Kozlowski wrote:
>>> On 14/04/2026 11:00, Alexey Klimov wrote:
>>>> On Mon Apr 13, 2026 at 4:23 PM BST, Krzysztof Kozlowski wrote:
>>>>> On 13/04/2026 16:52, Alexey Klimov wrote:
>>>>>> SRAM is used by the ACPM protocol to retrieve the ACPM channels
>>>>>> information and configuration data. Add the SRAM node.
>>>>>>
>>>>>> Signed-off-by: Alexey Klimov <alexey.klimov@xxxxxxxxxx>
>>>>>> ---
>>>>>>  arch/arm64/boot/dts/exynos/exynos850.dtsi | 8 ++++++++
>>>>>>  1 file changed, 8 insertions(+)
>>>>>>
>>>>>> diff --git a/arch/arm64/boot/dts/exynos/exynos850.dtsi b/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>>>>> index cb55015c8dce..cf4a6168846c 100644
>>>>>> --- a/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>>>>> +++ b/arch/arm64/boot/dts/exynos/exynos850.dtsi
>>>>>> @@ -910,6 +910,14 @@ spi_2: spi@11d20000 {
>>>>>>  			};
>>>>>>  		};
>>>>>>  	};
>>>>>> +
>>>>>> +	apm_sram: sram@2039000 {
>>>>>> +		compatible = "mmio-sram";
>>>>>> +		reg = <0x0 0x2039000 0x40000>;
>>>>>> +		#address-cells = <1>;
>>>>>> +		#size-cells = <1>;
>>>>>> +		ranges = <0x0 0x0 0x2039000 0x40000>;
>>>>>
>>>>> You miss here children.
>>>>
>>>> Thank you! I guess I should convert it to smth like this:
>>>>
>>>> apm_sram: sram@2039000 {
>>>> 		compatible = "mmio-sram";
>>>> 		reg = <0x0 0x2039000 0x40000>;
>>>> 		ranges = <0x0 0x0 0x2039000 0x40000>;
>>>> 		#address-cells = <1>;
>>>> 		#size-cells = <1>;
>>>>
>>>> 		acpm_sram_region: sram-section@0 {
>>>> 			reg = <0x0 0x40000>;
>>>
>>> This covers entire block, so feels pointless. Maybe requirement of
>>> children should be dropped. What's the point of having children? Why
>>> does the driver need them?
>> 
>> Thinking further about this. I was looking at the schema file and
>> different commits and it the right approach could be:
>> 
>> - add separate compatible for mmio-sram region for this case. Similar
>> to scmi and scpi, i'd say it should be "exynos,acpm-sram" or
>> "samsung,acpm-sram";
>> 
>> - update schema sram.yaml to exclude requirement for having child nodes
>> and properties like ranges, address and size cells
>> Similar like in commit, for instance, git show d0fe6491ddd22
>> (or git show 2d4a22e79a5fd).
>
> this works fine, but only if the sram is consumed as a whole, and only by
> ACPM. Is this the case for exynos850?

Sorry for the delay. Yes, as far as I am aware, this is a case for
exynos850 as well.

Thanks,
Alexey