dt-bindings: watchdog: renesas,wdt: Add support for RZ/T2H and RZ/N2H

Extend the Renesas WDT device tree bindings to support the watchdog timer
found on the RZ/T2H (R9A09G077) and RZ/N2H (R9A09G087) SoCs.

The RZ/T2H WDT is mostly compatible with the one found on the RZ/V2H(P),
but includes an additional register and differs in the clock division
ratio settings for the WDTCR[CKS] field. To reflect these differences,
introduce a new compatible string, "renesas,r9a09g077-wdt".

The binding schema is updated accordingly. On RZ/T2H, the WDT does not
require the "resets" property. It also requires two register regions and
the presence of a "power-domains" property. The "clock-names" property is
limited to a single entry, "pclk", for this SoC.

The RZ/N2H SoC uses the same WDT IP as the RZ/T2H. It is supported by
using "renesas,r9a09g087-wdt" as the primary compatible string, with
"renesas,r9a09g077-wdt" listed as a fallback to describe the shared
hardware features.

Example:
    wdt0: watchdog@80082000 {
        compatible = "renesas,r9a09g077-wdt";
        reg = <0 0x80082000 0 0x400>,
              <0 0x81295100 0 0x04>;
        clocks = <&cpg CPG_CORE R9A09G077_CLK_PCLKL>;
        clock-names = "pclk";
        power-domains = <&cpg>;
        status = "disabled";
    };

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Documentation/devicetree/bindings/watchdog/renesas,wdt.yaml

@@ -81,10 +81,17 @@ properties:
               - renesas,r9a09g056-wdt # RZ/V2N
           - const: renesas,r9a09g057-wdt # RZ/V2H(P)
 
-      - const: renesas,r9a09g057-wdt       # RZ/V2H(P)
+      - enum:
+          - renesas,r9a09g057-wdt    # RZ/V2H(P)
+          - renesas,r9a09g077-wdt    # RZ/T2H
+
+      - items:
+          - const: renesas,r9a09g087-wdt # RZ/N2H
+          - const: renesas,r9a09g077-wdt # RZ/T2H
 
   reg:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
 
   interrupts:
     minItems: 1
@@ -132,6 +139,7 @@ allOf:
           compatible:
             contains:
               enum:
+                - renesas,r9a09g077-wdt
                 - renesas,rza-wdt
                 - renesas,rzn1-wdt
     then:
@@ -183,7 +191,9 @@ allOf:
       properties:
         compatible:
           contains:
-            const: renesas,r9a09g057-wdt
+            enum:
+              - renesas,r9a09g057-wdt
+              - renesas,r9a09g077-wdt
     then:
       properties:
         interrupts: false
@@ -192,6 +202,26 @@ allOf:
       required:
         - interrupts
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: renesas,r9a09g077-wdt
+    then:
+      properties:
+        resets: false
+        clock-names:
+          maxItems: 1
+        reg:
+          minItems: 2
+      required:
+        - clock-names
+        - power-domains
+    else:
+      properties:
+        reg:
+          maxItems: 1
+
 additionalProperties: false
 
 examples: