spi: dt-bindings: renesas,rzv2h-rspi: document RZ/T2H and RZ/N2H

The Renesas RZ/T2H (R9A09G077) and RZ/N2H (R9A09G087) SoCs have four SPI
peripherals.

Compared to the previously supported RZ/V2H, these SoCs have a smaller
FIFO, no resets, and only two clocks: PCLKSPIn and PCLK. PCLKSPIn,
being the clock from which the SPI transfer clock is generated, is the
equivalent of the TCLK from V2H.

Document them, and use RZ/T2H as a fallback for RZ/N2H as the SPIs are
entirely compatible.

Signed-off-by: Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20251119161434.595677-11-cosmin-gabriel.tanislav.xa@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/renesas,rzv2h-rspi.yaml

@@ -9,12 +9,15 @@ title: Renesas RZ/V2H(P) Renesas Serial Peripheral Interface (RSPI)
 maintainers:
   - Fabrizio Castro <fabrizio.castro.jz@renesas.com>
 
-allOf:
-  - $ref: spi-controller.yaml#
-
 properties:
   compatible:
-    const: renesas,r9a09g057-rspi # RZ/V2H(P)
+    oneOf:
+      - enum:
+          - renesas,r9a09g057-rspi # RZ/V2H(P)
+          - renesas,r9a09g077-rspi # RZ/T2H
+      - items:
+          - const: renesas,r9a09g087-rspi # RZ/N2H
+          - const: renesas,r9a09g077-rspi # RZ/T2H
 
   reg:
     maxItems: 1
@@ -36,13 +39,12 @@ properties:
       - const: tx
 
   clocks:
+    minItems: 2
     maxItems: 3
 
   clock-names:
-    items:
-      - const: pclk
-      - const: pclk_sfr
-      - const: tclk
+    minItems: 2
+    maxItems: 3
 
   resets:
     maxItems: 2
@@ -62,12 +64,52 @@ required:
   - interrupt-names
   - clocks
   - clock-names
-  - resets
-  - reset-names
   - power-domains
   - '#address-cells'
   - '#size-cells'
 
+allOf:
+  - $ref: spi-controller.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - renesas,r9a09g057-rspi
+    then:
+      properties:
+        clocks:
+          minItems: 3
+
+        clock-names:
+          items:
+            - const: pclk
+            - const: pclk_sfr
+            - const: tclk
+
+      required:
+        - resets
+        - reset-names
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - renesas,r9a09g077-rspi
+    then:
+      properties:
+        clocks:
+          maxItems: 2
+
+        clock-names:
+          items:
+            - const: pclk
+            - const: pclkspi
+
+        resets: false
+        reset-names: false
+
 unevaluatedProperties: false
 
 examples: