dt-bindings: PCI: Add Qualcomm PCIe Endpoint controller

Add devicetree binding for Qualcomm PCIe Endpoint controller used in
platforms like SDX55. The Endpoint controller is based on the DesignWare
core with Qualcomm-specific wrappers.

Link: https://lore.kernel.org/r/20210920065946.15090-2-manivannan.sadhasivam@linaro.orgSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/qcom,pcie-ep.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm PCIe Endpoint Controller binding
+
+maintainers:
+  - Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+
+allOf:
+  - $ref: "pci-ep.yaml#"
+
+properties:
+  compatible:
+    const: qcom,sdx55-pcie-ep
+
+  reg:
+    items:
+      - description: Qualcomm-specific PARF configuration registers
+      - description: DesignWare PCIe registers
+      - description: External local bus interface registers
+      - description: Address Translation Unit (ATU) registers
+      - description: Memory region used to map remote RC address space
+      - description: BAR memory region
+
+  reg-names:
+    items:
+      - const: parf
+      - const: dbi
+      - const: elbi
+      - const: atu
+      - const: addr_space
+      - const: mmio
+
+  clocks:
+    items:
+      - description: PCIe Auxiliary clock
+      - description: PCIe CFG AHB clock
+      - description: PCIe Master AXI clock
+      - description: PCIe Slave AXI clock
+      - description: PCIe Slave Q2A AXI clock
+      - description: PCIe Sleep clock
+      - description: PCIe Reference clock
+
+  clock-names:
+    items:
+      - const: aux
+      - const: cfg
+      - const: bus_master
+      - const: bus_slave
+      - const: slave_q2a
+      - const: sleep
+      - const: ref
+
+  qcom,perst-regs:
+    description: Reference to a syscon representing TCSR followed by the two
+                 offsets within syscon for Perst enable and Perst separation
+                 enable registers
+    $ref: "/schemas/types.yaml#/definitions/phandle-array"
+    items:
+      minItems: 3
+      maxItems: 3
+
+  interrupts:
+    items:
+      - description: PCIe Global interrupt
+      - description: PCIe Doorbell interrupt
+
+  interrupt-names:
+    items:
+      - const: global
+      - const: doorbell
+
+  reset-gpios:
+    description: GPIO used as PERST# input signal
+    maxItems: 1
+
+  wake-gpios:
+    description: GPIO used as WAKE# output signal
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    const: core
+
+  power-domains:
+    maxItems: 1
+
+  phys:
+    maxItems: 1
+
+  phy-names:
+    const: pciephy
+
+  num-lanes:
+    default: 2
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - clock-names
+  - qcom,perst-regs
+  - interrupts
+  - interrupt-names
+  - reset-gpios
+  - resets
+  - reset-names
+  - power-domains
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/qcom,gcc-sdx55.h>
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    pcie_ep: pcie-ep@40000000 {
+        compatible = "qcom,sdx55-pcie-ep";
+        reg = <0x01c00000 0x3000>,
+              <0x40000000 0xf1d>,
+              <0x40000f20 0xc8>,
+              <0x40001000 0x1000>,
+              <0x40002000 0x1000>,
+              <0x01c03000 0x3000>;
+        reg-names = "parf", "dbi", "elbi", "atu", "addr_space",
+                    "mmio";
+
+        clocks = <&gcc GCC_PCIE_AUX_CLK>,
+             <&gcc GCC_PCIE_CFG_AHB_CLK>,
+             <&gcc GCC_PCIE_MSTR_AXI_CLK>,
+             <&gcc GCC_PCIE_SLV_AXI_CLK>,
+             <&gcc GCC_PCIE_SLV_Q2A_AXI_CLK>,
+             <&gcc GCC_PCIE_SLEEP_CLK>,
+             <&gcc GCC_PCIE_0_CLKREF_CLK>;
+        clock-names = "aux", "cfg", "bus_master", "bus_slave",
+                      "slave_q2a", "sleep", "ref";
+
+        qcom,perst-regs = <&tcsr 0xb258 0xb270>;
+
+        interrupts = <GIC_SPI 140 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 145 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "global", "doorbell";
+        reset-gpios = <&tlmm 57 GPIO_ACTIVE_LOW>;
+        wake-gpios = <&tlmm 53 GPIO_ACTIVE_LOW>;
+        resets = <&gcc GCC_PCIE_BCR>;
+        reset-names = "core";
+        power-domains = <&gcc PCIE_GDSC>;
+        phys = <&pcie0_lane>;
+        phy-names = "pciephy";
+        max-link-speed = <3>;
+        num-lanes = <2>;
+    };