dt-bindings: net: Add ICSS IEP

Add a DT binding document for the ICSS Industrial Ethernet Peripheral(IEP)
hardware. IEP supports packet timestamping, PTP and PPS.
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/ti,icss-iep.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/ti,icss-iep.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments ICSS Industrial Ethernet Peripheral (IEP) module
+
+maintainers:
+  - Md Danish Anwar <danishanwar@ti.com>
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - ti,am642-icss-iep
+              - ti,j721e-icss-iep
+          - const: ti,am654-icss-iep
+
+      - const: ti,am654-icss-iep
+
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+    description: phandle to the IEP source clock
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    /* AM65x */
+    icssg0_iep0: iep@2e000 {
+        compatible = "ti,am654-icss-iep";
+        reg = <0x2e000 0x1000>;
+        clocks = <&icssg0_iepclk_mux>;
+    };