dt-bindings: PCI: rcar: Add bindings for R-Car PCIe endpoint controller

This patch adds the bindings for the R-Car PCIe endpoint driver.

Link: https://lore.kernel.org/r/1588854799-13710-7-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: NLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Reviewed-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

Documentation/devicetree/bindings/pci/rcar-pci-ep.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2020 Renesas Electronics Europe GmbH - https://www.renesas.com/eu/en/
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/rcar-pci-ep.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas R-Car PCIe Endpoint
+
+maintainers:
+  - Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
+  - Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
+
+properties:
+  compatible:
+    items:
+      - const: renesas,r8a774c0-pcie-ep
+      - const: renesas,rcar-gen3-pcie-ep
+
+  reg:
+    maxItems: 5
+
+  reg-names:
+    items:
+      - const: apb-base
+      - const: memory0
+      - const: memory1
+      - const: memory2
+      - const: memory3
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: pcie
+
+  max-functions:
+    minimum: 1
+    maximum: 1
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - resets
+  - power-domains
+  - clocks
+  - clock-names
+  - max-functions
+
+examples:
+  - |
+    #include <dt-bindings/clock/r8a774c0-cpg-mssr.h>
+    #include <dt-bindings/power/r8a774c0-sysc.h>
+
+     pcie0_ep: pcie-ep@fe000000 {
+            compatible = "renesas,r8a774c0-pcie-ep",
+                         "renesas,rcar-gen3-pcie-ep";
+            reg = <0xfe000000 0x80000>,
+                  <0xfe100000 0x100000>,
+                  <0xfe200000 0x200000>,
+                  <0x30000000 0x8000000>,
+                  <0x38000000 0x8000000>;
+            reg-names = "apb-base", "memory0", "memory1", "memory2", "memory3";
+            resets = <&cpg 319>;
+            power-domains = <&sysc R8A774C0_PD_ALWAYS_ON>;
+            clocks = <&cpg CPG_MOD 319>;
+            clock-names = "pcie";
+            max-functions = /bits/ 8 <1>;
+    };