All supported SoCs have multiple DMA controllers that can be used with
the RSPI peripheral. The current bindings only allow a single pair of RX
and TX DMAs.

The DMA core allows specifying multiple DMAs with the same name, and it
will pick the first available one.

There is an exception in the base dt-schema rules specifically for
allowing this behavior (dtschema/schemas/dma/dma.yaml).

dma-names:
  anyOf:
    - uniqueItems: true
    - items:
        # Hack around Renesas bindings which repeat entries to support
        # multiple possible DMA providers
        enum: [rx, tx]

Allow multiple DMAs to have the same name and only restrict the possible
names of the DMA channels, not their count.

For RZ/T2H and RZ/N2H SoCs, limit the number of DMA channels to 6, as
they have 3 DMA controllers.

For RZ/V2H and RZ/V2N SoCs, limit the number of DMA channels to 10, as
they have 5 DMA controllers.

Signed-off-by: Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
---

V3:
 * impose proper maxItems for each device
 * impose maxItems for dmas property

V2:
 * new patch

 .../bindings/spi/renesas,rzv2h-rspi.yaml         | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml b/Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml
index a588b112e11e..cf8b733b766d 100644
--- a/Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml
+++ b/Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml
@@ -58,12 +58,16 @@ properties:
       - const: tresetn
 
   dmas:
-    maxItems: 2
+    minItems: 2
+    maxItems: 10
 
   dma-names:
+    minItems: 2
+    maxItems: 10
     items:
-      - const: rx
-      - const: tx
+      enum:
+        - rx
+        - tx
 
   power-domains:
     maxItems: 1
@@ -121,6 +125,12 @@ allOf:
         resets: false
         reset-names: false
 
+        dmas:
+          maxItems: 6
+
+        dma-names:
+          maxItems: 6
+
 unevaluatedProperties: false
 
 examples:
-- 
2.52.0

On Wed, Jan 28, 2026 at 11:51:30PM +0200, Cosmin Tanislav wrote:
> All supported SoCs have multiple DMA controllers that can be used with
> the RSPI peripheral. The current bindings only allow a single pair of RX
> and TX DMAs.
> 
> The DMA core allows specifying multiple DMAs with the same name, and it
> will pick the first available one.
> 
> There is an exception in the base dt-schema rules specifically for
> allowing this behavior (dtschema/schemas/dma/dma.yaml).
> 
> dma-names:
>   anyOf:
>     - uniqueItems: true
>     - items:
>         # Hack around Renesas bindings which repeat entries to support
>         # multiple possible DMA providers
>         enum: [rx, tx]
> 
> Allow multiple DMAs to have the same name and only restrict the possible
> names of the DMA channels, not their count.
> 
> For RZ/T2H and RZ/N2H SoCs, limit the number of DMA channels to 6, as
> they have 3 DMA controllers.

What's the rationale behind not setting minItems to 6 here

> 
> For RZ/V2H and RZ/V2N SoCs, limit the number of DMA channels to 10, as
> they have 5 DMA controllers.

and to 10 here? Do any of the spi controllers on these SoCs not have the
ability to use all of the available dma controllers?

> 
> Signed-off-by: Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
> ---
> 
> V3:
>  * impose proper maxItems for each device
>  * impose maxItems for dmas property
> 
> V2:
>  * new patch
> 
>  .../bindings/spi/renesas,rzv2h-rspi.yaml         | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml b/Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml
> index a588b112e11e..cf8b733b766d 100644
> --- a/Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml
> +++ b/Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml
> @@ -58,12 +58,16 @@ properties:
>        - const: tresetn
>  
>    dmas:
> -    maxItems: 2
> +    minItems: 2
> +    maxItems: 10
>  
>    dma-names:
> +    minItems: 2
> +    maxItems: 10
>      items:
> -      - const: rx
> -      - const: tx
> +      enum:
> +        - rx
> +        - tx
>  
>    power-domains:
>      maxItems: 1
> @@ -121,6 +125,12 @@ allOf:
>          resets: false
>          reset-names: false
>  
> +        dmas:
> +          maxItems: 6
> +
> +        dma-names:
> +          maxItems: 6
> +
>  unevaluatedProperties: false
>  
>  examples:
> -- 
> 2.52.0