dt-bindings: phy: Add Cadence MHDP PHY bindings in YAML format.

- Add Cadence MHDP PHY bindings in YAML format.
- Add Torrent PHY reference clock bindings.
- Add sub-node bindings for each group of PHY lanes based on PHY type.
  Each sub-node includes properties such as master lane number, link reset,
  phy type, number of lanes etc.
- Add reset support including PHY reset and individual lane reset.
- Add a new compatible string used for TI SoCs using Torrent PHY.
This will not affect ABI as the driver has never been functional,
and therefore do not exist in any active use case.
Signed-off-by: Yuti Amonkar <yamonkar@cadence.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/phy-cadence-torrent.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/phy/phy-cadence-torrent.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Cadence Torrent SD0801 PHY binding for DisplayPort
+
+description:
+  This binding describes the Cadence SD0801 PHY (also known as Torrent PHY)
+  hardware included with the Cadence MHDP DisplayPort controller.
+
+maintainers:
+  - Swapnil Jakhade <sjakhade@cadence.com>
+  - Yuti Amonkar <yamonkar@cadence.com>
+
+properties:
+  compatible:
+    enum:
+      - cdns,torrent-phy
+      - ti,j721e-serdes-10g
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+  clocks:
+    maxItems: 1
+    description:
+      PHY reference clock. Must contain an entry in clock-names.
+
+  clock-names:
+    const: refclk
+
+  reg:
+    minItems: 1
+    maxItems: 2
+    items:
+      - description: Offset of the Torrent PHY configuration registers.
+      - description: Offset of the DPTX PHY configuration registers.
+
+  reg-names:
+    minItems: 1
+    maxItems: 2
+    items:
+      - const: torrent_phy
+      - const: dptx_phy
+
+  resets:
+    maxItems: 1
+    description:
+      Torrent PHY reset.
+      See Documentation/devicetree/bindings/reset/reset.txt
+
+patternProperties:
+  '^phy@[0-7]+$':
+    type: object
+    description:
+      Each group of PHY lanes with a single master lane should be represented as a sub-node.
+    properties:
+      reg:
+        description:
+          The master lane number. This is the lowest numbered lane in the lane group.
+
+      resets:
+        minItems: 1
+        maxItems: 4
+        description:
+          Contains list of resets, one per lane, to get all the link lanes out of reset.
+
+      "#phy-cells":
+        const: 0
+
+      cdns,phy-type:
+        description:
+          Specifies the type of PHY for which the group of PHY lanes is used.
+          Refer include/dt-bindings/phy/phy.h. Constants from the header should be used.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [1, 2, 3, 4, 5, 6]
+
+      cdns,num-lanes:
+        description:
+          Number of DisplayPort lanes.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [1, 2, 4]
+        default: 4
+
+      cdns,max-bit-rate:
+        description:
+          Maximum DisplayPort link bit rate to use, in Mbps
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [2160, 2430, 2700, 3240, 4320, 5400, 8100]
+        default: 8100
+
+    required:
+      - reg
+      - resets
+      - "#phy-cells"
+      - cdns,phy-type
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - "#address-cells"
+  - "#size-cells"
+  - clocks
+  - clock-names
+  - reg
+  - reg-names
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/phy/phy.h>
+    torrent_phy: torrent-phy@f0fb500000 {
+          compatible = "cdns,torrent-phy";
+          reg = <0xf0 0xfb500000 0x0 0x00100000>,
+                <0xf0 0xfb030a00 0x0 0x00000040>;
+          reg-names = "torrent_phy", "dptx_phy";
+          resets = <&phyrst 0>;
+          clocks = <&ref_clk>;
+          clock-names = "refclk";
+          #address-cells = <1>;
+          #size-cells = <0>;
+          torrent_phy_dp: phy@0 {
+                    reg = <0>;
+                    resets = <&phyrst 1>, <&phyrst 2>,
+                             <&phyrst 3>, <&phyrst 4>;
+                    #phy-cells = <0>;
+                    cdns,phy-type = <PHY_TYPE_DP>;
+                    cdns,num-lanes = <4>;
+                    cdns,max-bit-rate = <8100>;
+          };
+    };
+...