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

[Tudor Ambarus <tudor.ambarus@linaro.org>]

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@linaro.org>
>>>>> ---
>>>>>  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?

Cheers,
ta