DWC USB3 DT node is supposed to be compliant with the Generic xHCI
Controller schema, but with additional vendor-specific properties, the
controller-specific reference clocks and PHYs. So let's convert the
currently available legacy text-based DWC USB3 bindings to the DT schema
and make sure the DWC USB3 nodes are also validated against the
usb-xhci.yaml schema.

Note we have to discard the nodename restriction of being prefixed with
"dwc3@" string, since in accordance with the usb-hcd.yaml schema USB nodes
are supposed to be named as "^usb(@.*)".

Signed-off-by: Serge Semin <redacted>

---

Changelog v2:
- Discard '|' from the descriptions, since we don't need to preserve
  the text formatting in any of them.
- Drop quotes from around the string constants.
- Fix the "clock-names" prop description to be referring the enumerated
  clock-names instead of the ones from the Databook.

Changelog v3:
- Apply usb-xhci.yaml# schema only if the controller is supposed to work
  as either host or otg.

Changelog v4:
- Apply usb-drd.yaml schema first. If the controller is configured
  to work in a gadget mode only, then apply the usb.yaml schema too,
  otherwise apply the usb-xhci.yaml schema.
- Discard the Rob'es Reviewed-by tag. Please review the patch one more
  time.
---
 .../devicetree/bindings/usb/dwc3.txt          | 125 --------
 .../devicetree/bindings/usb/snps,dwc3.yaml    | 303 ++++++++++++++++++
 2 files changed, 303 insertions(+), 125 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/usb/dwc3.txt
 create mode 100644 Documentation/devicetree/bindings/usb/snps,dwc3.yaml

diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
deleted file mode 100644
index d03edf9d3935..000000000000
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ /dev/null

@@ -1,125 +0,0 @@
-synopsys DWC3 CORE
-
-DWC3- USB3 CONTROLLER. Complies to the generic USB binding properties
-      as described in 'usb/generic.txt'
-
-Required properties:
- - compatible: must be "snps,dwc3"
- - reg : Address and length of the register set for the device
- - interrupts: Interrupts used by the dwc3 controller.
- - clock-names: list of clock names. Ideally should be "ref",
-                "bus_early", "suspend" but may be less or more.
- - clocks: list of phandle and clock specifier pairs corresponding to
-           entries in the clock-names property.
-
-Exception for clocks:
-  clocks are optional if the parent node (i.e. glue-layer) is compatible to
-  one of the following:
-    "cavium,octeon-7130-usb-uctl"
-    "qcom,dwc3"
-    "samsung,exynos5250-dwusb3"
-    "samsung,exynos5433-dwusb3"
-    "samsung,exynos7-dwusb3"
-    "sprd,sc9860-dwc3"
-    "st,stih407-dwc3"
-    "ti,am437x-dwc3"
-    "ti,dwc3"
-    "ti,keystone-dwc3"
-    "rockchip,rk3399-dwc3"
-    "xlnx,zynqmp-dwc3"