dt-bindings: PCI: rockchip: Add DT bindings for Rockchip PCIe controller

Add a binding that describes the Rockchip PCIe controller found on Rockchip
SoCs PCIe interface.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/rockchip-pcie.txt

+* Rockchip AXI PCIe Root Port Bridge DT description
+
+Required properties:
+- #address-cells: Address representation for root ports, set to <3>
+- #size-cells: Size representation for root ports, set to <2>
+- #interrupt-cells: specifies the number of cells needed to encode an
+		interrupt source. The value must be 1.
+- compatible: Should contain "rockchip,rk3399-pcie"
+- reg: Two register ranges as listed in the reg-names property
+- reg-names: Must include the following names
+	- "axi-base"
+	- "apb-base"
+- clocks: Must contain an entry for each entry in clock-names.
+		See ../clocks/clock-bindings.txt for details.
+- clock-names: Must include the following entries:
+	- "aclk"
+	- "aclk-perf"
+	- "hclk"
+	- "pm"
+- msi-map: Maps a Requester ID to an MSI controller and associated
+	msi-specifier data. See ./pci-msi.txt
+- phys: From PHY bindings: Phandle for the Generic PHY for PCIe.
+- phy-names:  MUST be "pcie-phy".
+- interrupts: Three interrupt entries must be specified.
+- interrupt-names: Must include the following names
+	- "sys"
+	- "legacy"
+	- "client"
+- resets: Must contain five entries for each entry in reset-names.
+	   See ../reset/reset.txt for details.
+- reset-names: Must include the following names
+	- "core"
+	- "mgmt"
+	- "mgmt-sticky"
+	- "pipe"
+- pinctrl-names : The pin control state names
+- pinctrl-0: The "default" pinctrl state
+- #interrupt-cells: specifies the number of cells needed to encode an
+	interrupt source. The value must be 1.
+- interrupt-map-mask and interrupt-map: standard PCI properties
+
+Optional Property:
+- ep-gpios: contain the entry for pre-reset gpio
+- num-lanes: number of lanes to use
+- vpcie3v3-supply: The phandle to the 3.3v regulator to use for PCIe.
+- vpcie1v8-supply: The phandle to the 1.8v regulator to use for PCIe.
+- vpcie0v9-supply: The phandle to the 0.9v regulator to use for PCIe.
+
+*Interrupt controller child node*
+The core controller provides a single interrupt for legacy INTx. The PCIe node
+should contain an interrupt controller node as a target for the PCI
+'interrupt-map' property. This node represents the domain at which the four
+INTx interrupts are decoded and routed.
+
+
+Required properties for Interrupt controller child node:
+- interrupt-controller: identifies the node as an interrupt controller
+- #address-cells: specifies the number of cells needed to encode an
+	address. The value must be 0.
+- #interrupt-cells: specifies the number of cells needed to encode an
+	interrupt source. The value must be 1.
+
+Example:
+
+pcie0: pcie@f8000000 {
+	compatible = "rockchip,rk3399-pcie";
+	#address-cells = <3>;
+	#size-cells = <2>;
+	clocks = <&cru ACLK_PCIE>, <&cru ACLK_PERF_PCIE>,
+		 <&cru PCLK_PCIE>, <&cru SCLK_PCIE_PM>;
+	clock-names = "aclk", "aclk-perf",
+		      "hclk", "pm";
+	bus-range = <0x0 0x1>;
+	interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH 0>,
+		     <GIC_SPI 50 IRQ_TYPE_LEVEL_HIGH 0>,
+		     <GIC_SPI 51 IRQ_TYPE_LEVEL_HIGH 0>;
+	interrupt-names = "sys", "legacy", "client";
+	assigned-clocks = <&cru SCLK_PCIEPHY_REF>;
+	assigned-clock-parents = <&cru SCLK_PCIEPHY_REF100M>;
+	assigned-clock-rates = <100000000>;
+	ep-gpios = <&gpio3 13 GPIO_ACTIVE_HIGH>;
+	ranges = <0x83000000 0x0 0xfa000000 0x0 0xfa000000 0x0 0x600000
+		  0x81000000 0x0 0xfa600000 0x0 0xfa600000 0x0 0x100000>;
+	num-lanes = <4>;
+	msi-map = <0x0 &its 0x0 0x1000>;
+	reg = <0x0 0xf8000000 0x0 0x2000000>, <0x0 0xfd000000 0x0 0x1000000>;
+	reg-names = "axi-base", "apb-base";
+	resets = <&cru SRST_PCIE_CORE>, <&cru SRST_PCIE_MGMT>,
+		 <&cru SRST_PCIE_MGMT_STICKY>, <&cru SRST_PCIE_PIPE>;
+	reset-names = "core", "mgmt", "mgmt-sticky", "pipe";
+	phys = <&pcie_phy>;
+	phy-names = "pcie-phy";
+	pinctrl-names = "default";
+	pinctrl-0 = <&pcie_clkreq>;
+	#interrupt-cells = <1>;
+	interrupt-map-mask = <0 0 0 7>;
+	interrupt-map = <0 0 0 1 &pcie0_intc 0>,
+			<0 0 0 2 &pcie0_intc 1>,
+			<0 0 0 3 &pcie0_intc 2>,
+			<0 0 0 4 &pcie0_intc 3>;
+	pcie0_intc: interrupt-controller {
+		interrupt-controller;
+		#address-cells = <0>;
+		#interrupt-cells = <1>;
+	};
+};