* Freescale i.MX6 PCIe interface

This PCIe host controller is based on the Synopsys DesignWare PCIe IP
and thus inherits all the common properties defined in designware-pcie.txt.

Required properties:
- compatible:
	- "fsl,imx6q-pcie"
	- "fsl,imx6sx-pcie",
	- "fsl,imx6qp-pcie"
	- "fsl,imx7d-pcie"
	- "fsl,imx8qm-pcie"
	- "fsl,imx8qxp-pcie"
	- "fsl,imx8mq-pcie"
	- "fsl,imx8mm-pcie"
- reg: base address and length of the PCIe controller
- interrupts: A list of interrupt outputs of the controller. Must contain an
  entry for each entry in the interrupt-names property.
- interrupt-names: Must include the following entries:
	- "msi": The interrupt that is asserted when an MSI is received
- clock-names: Must include the following additional entries:
	- "pcie_phy"
- ext_osc: use the external oscillator or not.
- hard-wired: the port is hard wired in hw design or not.

Optional properties:
- fsl,tx-deemph-gen1: Gen1 De-emphasis value. Default: 0
- fsl,tx-deemph-gen2-3p5db: Gen2 (3.5db) De-emphasis value. Default: 0
- fsl,tx-deemph-gen2-6db: Gen2 (6db) De-emphasis value. Default: 20
- fsl,tx-swing-full: Gen2 TX SWING FULL value. Default: 127
- fsl,tx-swing-low: TX launch amplitude swing_low value. Default: 127
- fsl,max-link-speed: Specify PCI gen for link capability. Must be '2' for
  gen2, otherwise will default to gen1. Note that the IMX6 LVDS clock outputs
  do not meet gen2 jitter requirements and thus for gen2 capability a gen2
  compliant clock generator should be used and configured.
- reset-gpio: Should specify the GPIO for controlling the PCI bus device reset
  signal. It's not polarity aware and defaults to active-low reset sequence
  (L=reset state, H=operation state).
- reset-gpio-active-high: If present then the reset sequence using the GPIO
  specified in the "reset-gpio" property is reversed (H=reset state,
  L=operation state).
- vpcie-supply: Should specify the regulator in charge of PCIe port power.
  The regulator will be enabled when initializing the PCIe host and
  disabled either as part of the init process or when shutting down the
  host.
- vph-supply: Should specify the regulator in charge of VPH one of the three
  PCIe PHY powers. This regulator can be supplied by both 1.8v and 3.3v voltage
  supplies. Might be used to distinguish different HW board designs.

Additional required properties for imx6sx-pcie:
- clock names: Must include the following additional entries:
	- "pcie_inbound_axi"

Additional required properties for imx7d-pcie:
- power-domains: Must be set to a phandle pointing to PCIE_PHY power domain
- resets: Must contain phandles to PCIe-related reset lines exposed by SRC
  IP block
- reset-names: Must contain the following entires:
	       - "pciephy"
	       - "apps"

Additional required properties for imx8 pcie:
- hsio : should be <&hsio>.
   The phandle points to the hsio region containing the hsio
   such as the pcie and sata control registers.
- hsio-cfg: hsio configration mode when the pcie node is supported.
  mode 1: pciea 2 lanes and one sata ahci port.
  mode 2: pciea 1 lane, pcieb 1 lane and one sata ahci port.
  mode 3: pciea 2 lanes, pcieb 1 lane.
- ctrl-id: used to distinguish pciea or pcieb.
  0: pciea, 1: pcieb.
- cpu-base-addr: the base cpu address mapped from hsio address.
	Example:
		hsio-cfg = <PCIEAX1PCIEBX1SATA>;
		hsio = <&hsio>;
		ctrl-id = <0>; /* pciea */
		cpu-base-addr = <0x40000000>;

Example:

	pcie@0x01000000 {
		compatible = "fsl,imx6q-pcie", "snps,dw-pcie";
		reg = <0x01ffc000 0x04000>,
		      <0x01f00000 0x80000>;
		reg-names = "dbi", "config";
		#address-cells = <3>;
		#size-cells = <2>;
		device_type = "pci";
		ranges = <0x00000800 0 0x01f00000 0x01f00000 0 0x00080000
			  0x81000000 0 0          0x01f80000 0 0x00010000
			  0x82000000 0 0x01000000 0x01000000 0 0x00f00000>;
		num-lanes = <1>;
		interrupts = <GIC_SPI 120 IRQ_TYPE_LEVEL_HIGH>;
		interrupt-names = "msi";
		#interrupt-cells = <1>;
		interrupt-map-mask = <0 0 0 0x7>;
		interrupt-map = <0 0 0 1 &intc GIC_SPI 123 IRQ_TYPE_LEVEL_HIGH>,
		                <0 0 0 2 &intc GIC_SPI 122 IRQ_TYPE_LEVEL_HIGH>,
		                <0 0 0 3 &intc GIC_SPI 121 IRQ_TYPE_LEVEL_HIGH>,
		                <0 0 0 4 &intc GIC_SPI 120 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&clks 144>, <&clks 206>, <&clks 189>;
		clock-names = "pcie", "pcie_bus", "pcie_phy";
	};