dt-bindings: arm: sparx5: Add documentation for Microchip Sparx5 SoC

This adds the main Sparx5 SoC DT documentation file, with information
abut the supported board types.

Link: https://lore.kernel.org/r/20200615133242.24911-2-lars.povlsen@microchip.comReviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lars Povlsen <lars.povlsen@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/arm/microchip,sparx5.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/microchip,sparx5.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip Sparx5 Boards Device Tree Bindings
+
+maintainers:
+  - Lars Povlsen <lars.povlsen@microchip.com>
+
+description: |+
+   The Microchip Sparx5 SoC is a ARMv8-based used in a family of
+   gigabit TSN-capable gigabit switches.
+
+   The SparX-5 Ethernet switch family provides a rich set of switching
+   features such as advanced TCAM-based VLAN and QoS processing
+   enabling delivery of differentiated services, and security through
+   TCAM-based frame processing using versatile content aware processor
+   (VCAP)
+
+properties:
+  $nodename:
+    const: '/'
+  compatible:
+    oneOf:
+      - description: The Sparx5 pcb125 board is a modular board,
+          which has both spi-nor and eMMC storage. The modular design
+          allows for connection of different network ports.
+        items:
+          - const: microchip,sparx5-pcb125
+          - const: microchip,sparx5
+
+      - description: The Sparx5 pcb134 is a pizzabox form factor
+          gigabit switch with 20 SFP ports. It features spi-nor and
+          either spi-nand or eMMC storage (mount option).
+        items:
+          - const: microchip,sparx5-pcb134
+          - const: microchip,sparx5
+
+      - description: The Sparx5 pcb135 is a pizzabox form factor
+          gigabit switch with 48+4 Cu ports. It features spi-nor and
+          either spi-nand or eMMC storage (mount option).
+        items:
+          - const: microchip,sparx5-pcb135
+          - const: microchip,sparx5
+
+  axi@600000000:
+    type: object
+    description: the root node in the Sparx5 platforms must contain
+      an axi bus child node. They are always at physical address
+      0x600000000 in all the Sparx5 variants.
+    properties:
+      compatible:
+        items:
+          - const: simple-bus
+
+    required:
+      - compatible
+
+required:
+  - compatible
+  - axi@600000000
+
+...

Documentation/devicetree/bindings/mfd/syscon.yaml

@@ -38,6 +38,7 @@ properties:
               - allwinner,sun8i-h3-system-controller
               - allwinner,sun8i-v3s-system-controller
               - allwinner,sun50i-a64-system-controller
+              - microchip,sparx5-cpu-syscon
 
           - const: syscon