dt-bindings: Add USB PHY bindings

Add USB PHY bindings used on MSM platforms.

Change-Id: Ifaf30337abc9b48ccad01f9b4d9aedfb877820f4
Signed-off-by: Ronak Vijay Raheja <quic_rraheja@quicinc.com>

bindings/usb/qcom,usb-emu-phy.yaml

@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/qcom,usb-emu-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Technologies, Inc. emulation USB PHY
+
+maintainers:
+  - Ronak Vijay Raheja <quic_rraheja@quicinc.com>
+
+properties:
+  compatible:
+    const: qcom,usb-emu-phy
+
+  reg:
+    description: |
+      Offset and length of the register set in the memory map. Additional
+      offset and length of register set for QSCRATCH wrapper.
+    minItems: 1
+    maxItems: 2
+
+  reg-names:
+    items:
+      - const: base
+      - const: qscratch_base
+
+  qcom,emu-init-seq:
+    description: emulation initialization sequence of value,reg pairs
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - qcom,emu-init-seq
+
+additionalProperties: false
+
+examples:
+  - |
+    usb_emu_phy@a720000 {
+      compatible = "qcom,usb-emu-phy";
+      reg = <0x0a720000 0x9500>,
+            <0x0a6f8800 0x100>;
+      reg-names = "base", "qscratch_base";
+
+      qcom,emu-init-seq = <0xfff0 0x4
+                           0xfff3 0x4
+                           0xfff0 0x4
+                           0x100000 0x20
+                           0x0 0x20
+                           0x1a0 0x20
+                           0x100000 0x3c
+                           0x0 0x3c
+                           0x10060 0x3c
+                           0x0 0x4>;
+    };
+...