dt-bindings: soc: starfive: Add StarFive syscon module

Add documentation to describe StarFive System Controller Registers.
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Co-developed-by: Xingyu Wu <xingyu.wu@starfivetech.com>
Signed-off-by: Xingyu Wu <xingyu.wu@starfivetech.com>
Signed-off-by: William Qiu <william.qiu@starfivetech.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Documentation/devicetree/bindings/soc/starfive/starfive,jh7110-syscon.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/starfive/starfive,jh7110-syscon.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive JH7110 SoC system controller
+
+maintainers:
+  - William Qiu <william.qiu@starfivetech.com>
+
+description:
+  The StarFive JH7110 SoC system controller provides register information such
+  as offset, mask and shift to configure related modules such as MMC and PCIe.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: starfive,jh7110-sys-syscon
+          - const: syscon
+          - const: simple-mfd
+      - items:
+          - enum:
+              - starfive,jh7110-aon-syscon
+              - starfive,jh7110-stg-syscon
+          - const: syscon
+
+  reg:
+    maxItems: 1
+
+  clock-controller:
+    $ref: /schemas/clock/starfive,jh7110-pll.yaml#
+    type: object
+
+  "#power-domain-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: starfive,jh7110-sys-syscon
+    then:
+      required:
+        - clock-controller
+    else:
+      properties:
+        clock-controller: false
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: starfive,jh7110-aon-syscon
+    then:
+      required:
+        - "#power-domain-cells"
+    else:
+      properties:
+        "#power-domain-cells": false
+
+additionalProperties: false
+
+examples:
+  - |
+    syscon@10240000 {
+        compatible = "starfive,jh7110-stg-syscon", "syscon";
+        reg = <0x10240000 0x1000>;
+    };
+
+    syscon@13030000 {
+        compatible = "starfive,jh7110-sys-syscon", "syscon", "simple-mfd";
+        reg = <0x13030000 0x1000>;
+
+        clock-controller {
+            compatible = "starfive,jh7110-pll";
+            clocks = <&osc>;
+            #clock-cells = <1>;
+        };
+    };
+
+    syscon@17010000 {
+        compatible = "starfive,jh7110-aon-syscon", "syscon";
+        reg = <0x17010000 0x1000>;
+        #power-domain-cells = <1>;
+    };
+
+...

MAINTAINERS

@@ -20271,6 +20271,12 @@ S:	Supported
 F:	Documentation/devicetree/bindings/mmc/starfive*
 F:	drivers/mmc/host/dw_mmc-starfive.c
 
+STARFIVE JH7110 SYSCON
+M:	William Qiu <william.qiu@starfivetech.com>
+M:	Xingyu Wu <xingyu.wu@starfivetech.com>
+S:	Supported
+F:	Documentation/devicetree/bindings/soc/starfive/starfive,jh7110-syscon.yaml
+
 STARFIVE JH7110 TDM DRIVER
 M:	Walker Chen <walker.chen@starfivetech.com>
 S:	Maintained
@@ -20320,6 +20326,7 @@ STARFIVE SOC DRIVERS
 M:	Conor Dooley <conor@kernel.org>
 S:	Maintained
 T:	git https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux.git/
+F:	Documentation/devicetree/bindings/soc/starfive/
 F:	drivers/soc/starfive/
 
 STARFIVE TRNG DRIVER