dt-bindings: PCI: intel: Add YAML schemas for the PCIe RC controller

Add YAML schemas for PCIe RC controller on Intel Gateway SoCs
which is Synopsys DesignWare based PCIe core.
Signed-off-by: Dilip Kota <eswara.kota@linux.intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/intel-gw-pcie.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/intel-gw-pcie.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: PCIe RC controller on Intel Gateway SoCs
+
+maintainers:
+  - Dilip Kota <eswara.kota@linux.intel.com>
+
+properties:
+  compatible:
+    items:
+      - const: intel,lgm-pcie
+      - const: snps,dw-pcie
+
+  device_type:
+    const: pci
+
+  "#address-cells":
+    const: 3
+
+  "#size-cells":
+    const: 2
+
+  reg:
+    items:
+      - description: Controller control and status registers.
+      - description: PCIe configuration registers.
+      - description: Controller application registers.
+
+  reg-names:
+    items:
+      - const: dbi
+      - const: config
+      - const: app
+
+  ranges:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  phys:
+    maxItems: 1
+
+  phy-names:
+    const: pcie
+
+  reset-gpios:
+    maxItems: 1
+
+  linux,pci-domain: true
+
+  num-lanes:
+    maximum: 2
+    description: Number of lanes to use for this port.
+
+  '#interrupt-cells':
+    const: 1
+
+  interrupt-map-mask:
+    description: Standard PCI IRQ mapping properties.
+
+  interrupt-map:
+    description: Standard PCI IRQ mapping properties.
+
+  max-link-speed:
+    description: Specify PCI Gen for link capability.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - enum: [ 1, 2, 3, 4 ]
+      - default: 1
+
+  bus-range:
+    description: Range of bus numbers associated with this controller.
+
+  reset-assert-ms:
+    description: |
+      Delay after asserting reset to the PCIe device.
+    maximum: 500
+    default: 100
+
+required:
+  - compatible
+  - device_type
+  - "#address-cells"
+  - "#size-cells"
+  - reg
+  - reg-names
+  - ranges
+  - resets
+  - clocks
+  - phys
+  - phy-names
+  - reset-gpios
+  - '#interrupt-cells'
+  - interrupt-map
+  - interrupt-map-mask
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/clock/intel,lgm-clk.h>
+    pcie10: pcie@d0e00000 {
+      compatible = "intel,lgm-pcie", "snps,dw-pcie";
+      device_type = "pci";
+      #address-cells = <3>;
+      #size-cells = <2>;
+      reg = <0xd0e00000 0x1000>,
+            <0xd2000000 0x800000>,
+            <0xd0a41000 0x1000>;
+      reg-names = "dbi", "config", "app";
+      linux,pci-domain = <0>;
+      max-link-speed = <4>;
+      bus-range = <0x00 0x08>;
+      interrupt-parent = <&ioapic1>;
+      #interrupt-cells = <1>;
+      interrupt-map-mask = <0 0 0 0x7>;
+      interrupt-map = <0 0 0 1 &ioapic1 27 1>,
+                      <0 0 0 2 &ioapic1 28 1>,
+                      <0 0 0 3 &ioapic1 29 1>,
+                      <0 0 0 4 &ioapic1 30 1>;
+      ranges = <0x02000000 0 0xd4000000 0xd4000000 0 0x04000000>;
+      resets = <&rcu0 0x50 0>;
+      clocks = <&cgu0 LGM_GCLK_PCIE10>;
+      phys = <&cb0phy0>;
+      phy-names = "pcie";
+      reset-assert-ms = <500>;
+      reset-gpios = <&gpio0 3 GPIO_ACTIVE_LOW>;
+      num-lanes = <2>;
+    };