Re: [PATCH v5 2/3] dt-bindings: mfd: aspeed,ast2x00-scu: Describe AST2700 SCU0

Billy Tsai
2026-04-02T06:14:10Z

> > AST2700 consists of two interconnected SoC instances, each with its own
> > System Control Unit (SCU). The SCU0 provides pin control, interrupt
> > controllers, clocks, resets, and address-space mappings for the
> > Secondary and Tertiary Service Processors (SSP and TSP).
> >
> > Describe the SSP/TSP address mappings using the standard
> > memory-region and memory-region-names properties.
> >
> > Disallow legacy child nodes that are not present on AST2700, including
> > p2a-control and smp-memram. The latter is unnecessary as software can
> > access the scratch registers via the SCU syscon.
> >
> > Also allow the AST2700 SoC0 pin controller to be described as a child
> > node of the SCU0, and add an example illustrating the SCU0 layout,
> > including reserved-memory, interrupt controllers, and pinctrl.
> >
> > Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
> > ---
> > .../bindings/mfd/aspeed,ast2x00-scu.yaml | 117 +++++++++++++++++++++
> > 1 file changed, 117 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/mfd/aspeed,ast2x00-scu.yaml b/Documentation/devicetree/bindings/mfd/aspeed,ast2x00-scu.yaml
> > index a87f31fce019..86d51389689c 100644
> > --- a/Documentation/devicetree/bindings/mfd/aspeed,ast2x00-scu.yaml
> > +++ b/Documentation/devicetree/bindings/mfd/aspeed,ast2x00-scu.yaml
> > @@ -46,6 +46,9 @@ properties:
> > '#reset-cells':
> > const: 1
> >
> > + memory-region: true
> > + memory-region-names: true

> Missing constraints. From where did you take such syntax (so I can fix
> it)?

The intention was to constrain these properties conditionally for
AST2700 SCU0 as done further down in the patch.

I can update the binding so that memory-region and memory-region-names
have baseline constraints (e.g. minItems and maxItems), and then refine them in the
conditional branches for AST2700SCU0, AST2700SCU1 and others

memory-region:
minItems: 2
maxItems: 3
memory-region-names:
minItems: 2
maxItems: 3

Best regards,
Billy Tsai