dt-bindings: fsi: Document the AST2700 FSI controller

Add the appropriate compatible string, and document the new reg
properties of the AST2700 FSI controller, which can directly access
the FSI controller registers as well as the FSI link address space.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240522192524.3286237-10-eajames@linux.ibm.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

Documentation/devicetree/bindings/fsi/aspeed,ast2600-fsi-master.yaml

@@ -17,9 +17,7 @@ properties:
   compatible:
     enum:
       - aspeed,ast2600-fsi-master
-
-  reg:
-    maxItems: 1
+      - aspeed,ast2700-fsi-master
 
   clocks:
     maxItems: 1
@@ -42,6 +40,30 @@ properties:
   interrupts:
     maxItems: 1
 
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - aspeed,ast2600-fsi-master
+then:
+  properties:
+    reg:
+      maxItems: 1
+else:
+  properties:
+    reg:
+      minItems: 1
+      items:
+        - description: OPB control registers
+        - description: FSI controller registers
+        - description: FSI link address space
+    reg-names:
+      items:
+        - const: opb
+        - const: ctrl
+        - const: fsi
+
 required:
   - compatible
   - reg
@@ -78,3 +100,22 @@ examples:
             chip-id = <0>;
         };
     };
+  - |
+    bus {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        fsi-master@21800000 {
+            compatible = "aspeed,ast2700-fsi-master";
+            reg = <0x0 0x21800000 0x0 0x100>,
+                  <0x0 0x21000000 0x0 0x1000>,
+                  <0x0 0x20000000 0x0 0x1000000>;
+            reg-names = "opb", "ctrl", "fsi";
+            #interrupt-cells = <1>;
+            interrupt-controller;
+            interrupts-extended = <&intc 6>;
+            pinctrl-names = "default";
+            pinctrl-0 = <&pinctrl_fsi0_default>;
+            clocks = <&syscon 40>;
+        };
+    };