dt-bindings: usb: dwc3-imx8mp: add imx8mp dwc3 glue bindings

NXP imx8mp integrates 2 dwc3 3.30b IP and add some wakeup logic
to support low power mode, the glue layer is for this wakeup
functionality, which has a separated interrupt, can support
wakeup from U3 and connect events for host, and vbus wakeup for
device.
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Li Jun <jun.li@nxp.com>
Link: https://lore.kernel.org/r/1609241866-9508-2-git-send-email-jun.li@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/fsl,imx8mp-dwc3.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (c) 2020 NXP
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/fsl,imx8mp-dwc3.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP iMX8MP Soc USB Controller
+
+maintainers:
+  - Li Jun <jun.li@nxp.com>
+
+properties:
+  compatible:
+    const: fsl,imx8mp-dwc3
+
+  reg:
+    maxItems: 1
+    description: Address and length of the register set for the wrapper of
+      dwc3 core on the SOC.
+
+  "#address-cells":
+    enum: [ 1, 2 ]
+
+  "#size-cells":
+    enum: [ 1, 2 ]
+
+  dma-ranges:
+    description:
+      See section 2.3.9 of the DeviceTree Specification.
+
+  ranges: true
+
+  interrupts:
+    maxItems: 1
+    description: The interrupt that is asserted when a wakeup event is
+      received.
+
+  clocks:
+    description:
+      A list of phandle and clock-specifier pairs for the clocks
+      listed in clock-names.
+    items:
+      - description: system hsio root clock.
+      - description: suspend clock, used for usb wakeup logic.
+
+  clock-names:
+    items:
+      - const: hsio
+      - const: suspend
+
+# Required child node:
+
+patternProperties:
+  "^dwc3@[0-9a-f]+$":
+    type: object
+    description:
+      A child node must exist to represent the core DWC3 IP block
+      The content of the node is defined in dwc3.txt.
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+  - dma-ranges
+  - ranges
+  - clocks
+  - clock-names
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/imx8mp-clock.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    usb3_0: usb@32f10100 {
+      compatible = "fsl,imx8mp-dwc3";
+      reg = <0x32f10100 0x8>;
+      clocks = <&clk IMX8MP_CLK_HSIO_ROOT>,
+               <&clk IMX8MP_CLK_USB_ROOT>;
+      clock-names = "hsio", "suspend";
+      interrupts = <GIC_SPI 148 IRQ_TYPE_LEVEL_HIGH>;
+      #address-cells = <1>;
+      #size-cells = <1>;
+      dma-ranges = <0x40000000 0x40000000 0xc0000000>;
+      ranges;
+
+      dwc3@38100000 {
+        compatible = "snps,dwc3";
+        reg = <0x38100000 0x10000>;
+        clocks = <&clk IMX8MP_CLK_HSIO_AXI>,
+                 <&clk IMX8MP_CLK_USB_CORE_REF>,
+                 <&clk IMX8MP_CLK_USB_ROOT>;
+        clock-names = "bus_early", "ref", "suspend";
+        assigned-clocks = <&clk IMX8MP_CLK_HSIO_AXI>;
+        assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_500M>;
+        assigned-clock-rates = <500000000>;
+        interrupts = <GIC_SPI 40 IRQ_TYPE_LEVEL_HIGH>;
+        phys = <&usb3_phy0>, <&usb3_phy0>;
+        phy-names = "usb2-phy", "usb3-phy";
+        snps,dis-u2-freeclk-exists-quirk;
+      };
+    };