dt-bindings: PCI: qcom,sa8255p-pcie-ep: Document firmware managed PCIe endpoint

Document the required configuration to enable the PCIe Endpoint controller
on SA8255p which is managed by firmware using power-domain based handling.

Signed-off-by: Mrinmay Sarkar <mrinmay.sarkar@oss.qualcomm.com>
[mani: added MAINTAINERS entry]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260106-firmware_managed_ep-v5-1-1933432127ec@oss.qualcomm.com

Author: Mrinmay Sarkar

Documentation/devicetree/bindings/pci/qcom,sa8255p-pcie-ep.yaml

@@ -0,0 +1,110 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/qcom,sa8255p-pcie-ep.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm firmware managed PCIe Endpoint Controller
+
+description:
+  Qualcomm SA8255p SoC PCIe endpoint controller is based on the Synopsys
+  DesignWare PCIe IP which is managed by firmware.
+
+maintainers:
+  - Manivannan Sadhasivam <mani@kernel.org>
+
+properties:
+  compatible:
+    const: qcom,sa8255p-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
+      - description: DMA register space
+
+  reg-names:
+    items:
+      - const: parf
+      - const: dbi
+      - const: elbi
+      - const: atu
+      - const: addr_space
+      - const: mmio
+      - const: dma
+
+  interrupts:
+    items:
+      - description: PCIe Global interrupt
+      - description: PCIe Doorbell interrupt
+      - description: DMA interrupt
+
+  interrupt-names:
+    items:
+      - const: global
+      - const: doorbell
+      - const: dma
+
+  iommus:
+    maxItems: 1
+
+  reset-gpios:
+    description: GPIO used as PERST# input signal
+    maxItems: 1
+
+  wake-gpios:
+    description: GPIO used as WAKE# output signal
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  dma-coherent: true
+
+  num-lanes:
+    default: 2
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - interrupt-names
+  - reset-gpios
+  - power-domains
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+        pcie1_ep: pcie-ep@1c10000 {
+            compatible = "qcom,sa8255p-pcie-ep";
+            reg = <0x0 0x01c10000 0x0 0x3000>,
+                  <0x0 0x60000000 0x0 0xf20>,
+                  <0x0 0x60000f20 0x0 0xa8>,
+                  <0x0 0x60001000 0x0 0x4000>,
+                  <0x0 0x60200000 0x0 0x100000>,
+                  <0x0 0x01c13000 0x0 0x1000>,
+                  <0x0 0x60005000 0x0 0x2000>;
+            reg-names = "parf", "dbi", "elbi", "atu", "addr_space", "mmio", "dma";
+            interrupts = <GIC_SPI 518 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 152 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 474 IRQ_TYPE_LEVEL_HIGH>;
+            interrupt-names = "global", "doorbell", "dma";
+            reset-gpios = <&tlmm 4 GPIO_ACTIVE_LOW>;
+            wake-gpios = <&tlmm 5 GPIO_ACTIVE_LOW>;
+            dma-coherent;
+            iommus = <&pcie_smmu 0x80 0x7f>;
+            power-domains = <&scmi6_pd 1>;
+            num-lanes = <4>;
+        };
+    };

MAINTAINERS

@@ -20357,6 +20357,7 @@ L:	linux-pci@vger.kernel.org
 L:	linux-arm-msm@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml
+F:	Documentation/devicetree/bindings/pci/qcom,sa8255p-pcie-ep.yaml
 F:	drivers/pci/controller/dwc/pcie-qcom-common.c
 F:	drivers/pci/controller/dwc/pcie-qcom-ep.c