dt-bindings: net: pse-dt: add bindings for regulator based PoDL PSE controller

Add bindings for the regulator based Ethernet PoDL PSE controller and
generic bindings for all PSE controllers.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/devicetree/bindings/net/pse-pd/podl-pse-regulator.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/pse-pd/podl-pse-regulator.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Regulator based Power Sourcing Equipment
+
+maintainers:
+  - Oleksij Rempel <o.rempel@pengutronix.de>
+
+description: Regulator based PoDL PSE controller. The device must be referenced
+  by the PHY node to control power injection to the Ethernet cable.
+
+allOf:
+  - $ref: "pse-controller.yaml#"
+
+properties:
+  compatible:
+    const: podl-pse-regulator
+
+  '#pse-cells':
+    const: 0
+
+  pse-supply:
+    description: Power supply for the PSE controller
+
+additionalProperties: false
+
+required:
+  - compatible
+  - pse-supply
+
+examples:
+  - |
+    ethernet-pse {
+      compatible = "podl-pse-regulator";
+      pse-supply = <&reg_t1l1>;
+      #pse-cells = <0>;
+    };

Documentation/devicetree/bindings/net/pse-pd/pse-controller.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/pse-pd/pse-controller.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Power Sourcing Equipment (PSE).
+
+description: Binding for the Power Sourcing Equipment (PSE) as defined in the
+  IEEE 802.3 specification. It is designed for hardware which is delivering
+  power over twisted pair/ethernet cable. The ethernet-pse nodes should be
+  used to describe PSE controller and referenced by the ethernet-phy node.
+
+maintainers:
+  - Oleksij Rempel <o.rempel@pengutronix.de>
+
+properties:
+  $nodename:
+    pattern: "^ethernet-pse(@.*)?$"
+
+  "#pse-cells":
+    description:
+      Used to uniquely identify a PSE instance within an IC. Will be
+      0 on PSE nodes with only a single output and at least 1 on nodes
+      controlling several outputs.
+    enum: [0, 1]
+
+required:
+  - "#pse-cells"
+
+additionalProperties: true
+
+...