PCI: rcar: Add gen2 device tree support

Add device tree probing support to the 'pci-rcar-gen2' driver.

[Sergei: numerous fixes/cleanups/additions]
[bhelgaas: whitespace fix]
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/pci/pci-rcar-gen2.txt

+Renesas AHB to PCI bridge
+-------------------------
+
+This is the bridge used internally to connect the USB controllers to the
+AHB. There is one bridge instance per USB port connected to the internal
+OHCI and EHCI controllers.
+
+Required properties:
+- compatible: "renesas,pci-r8a7790" for the R8A7790 SoC;
+	      "renesas,pci-r8a7791" for the R8A7791 SoC.
+- reg:	A list of physical regions to access the device: the first is
+	the operational registers for the OHCI/EHCI controllers and the
+	second is for the bridge configuration and control registers.
+- interrupts: interrupt for the device.
+- clocks: The reference to the device clock.
+- bus-range: The PCI bus number range; as this is a single bus, the range
+	     should be specified as the same value twice.
+- #address-cells: must be 3.
+- #size-cells: must be 2.
+- #interrupt-cells: must be 1.
+- interrupt-map: standard property used to define the mapping of the PCI
+  interrupts to the GIC interrupts.
+- interrupt-map-mask: standard property that helps to define the interrupt
+  mapping.
+
+Example SoC configuration:
+
+	pci0: pci@ee090000  {
+		compatible = "renesas,pci-r8a7790";
+		clocks = <&mstp7_clks R8A7790_CLK_EHCI>;
+		reg = <0x0 0xee090000 0x0 0xc00>,
+		      <0x0 0xee080000 0x0 0x1100>;
+		interrupts = <0 108 IRQ_TYPE_LEVEL_HIGH>;
+		status = "disabled";
+
+		bus-range = <0 0>;
+		#address-cells = <3>;
+		#size-cells = <2>;
+		#interrupt-cells = <1>;
+		interrupt-map-mask = <0xff00 0 0 0x7>;
+		interrupt-map = <0x0000 0 0 1 &gic 0 108 IRQ_TYPE_LEVEL_HIGH
+				 0x0800 0 0 1 &gic 0 108 IRQ_TYPE_LEVEL_HIGH
+				 0x1000 0 0 2 &gic 0 108 IRQ_TYPE_LEVEL_HIGH>;
+
+		pci@0,1 {
+			reg = <0x800 0 0 0 0>;
+			device_type = "pci";
+			phys = <&usbphy 0 0>;
+			phy-names = "usb";
+		};
+
+		pci@0,2 {
+			reg = <0x1000 0 0 0 0>;
+			device_type = "pci";
+			phys = <&usbphy 0 0>;
+			phy-names = "usb";
+		};
+	};
+
+Example board setup:
+
+&pci0 {
+	status = "okay";
+	pinctrl-0 = <&usb0_pins>;
+	pinctrl-names = "default";
+};

drivers/pci/host/pci-rcar-gen2.c

@@ -99,6 +99,7 @@ struct rcar_pci_priv {
 	struct resource io_res;
 	struct resource mem_res;
 	struct resource *cfg_res;
+	unsigned busnr;
 	int irq;
 	unsigned long window_size;
 };
@@ -318,8 +319,8 @@ static int rcar_pci_setup(int nr, struct pci_sys_data *sys)
 	pci_add_resource(&sys->resources, &priv->io_res);
 	pci_add_resource(&sys->resources, &priv->mem_res);
 
-	/* Setup bus number based on platform device id */
-	sys->busnr = to_platform_device(priv->dev)->id;
+	/* Setup bus number based on platform device id / of bus-range */
+	sys->busnr = priv->busnr;
 	return 1;
 }
 
@@ -372,6 +373,23 @@ static int rcar_pci_probe(struct platform_device *pdev)
 
 	priv->window_size = SZ_1G;
 
+	if (pdev->dev.of_node) {
+		struct resource busnr;
+		int ret;
+
+		ret = of_pci_parse_bus_range(pdev->dev.of_node, &busnr);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "failed to parse bus-range\n");
+			return ret;
+		}
+
+		priv->busnr = busnr.start;
+		if (busnr.end != busnr.start)
+			dev_warn(&pdev->dev, "only one bus number supported\n");
+	} else {
+		priv->busnr = pdev->id;
+	}
+
 	hw_private[0] = priv;
 	memset(&hw, 0, sizeof(hw));
 	hw.nr_controllers = ARRAY_SIZE(hw_private);
@@ -383,11 +401,20 @@ static int rcar_pci_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static struct of_device_id rcar_pci_of_match[] = {
+	{ .compatible = "renesas,pci-r8a7790", },
+	{ .compatible = "renesas,pci-r8a7791", },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, rcar_pci_of_match);
+
 static struct platform_driver rcar_pci_driver = {
 	.driver = {
 		.name = "pci-rcar-gen2",
 		.owner = THIS_MODULE,
 		.suppress_bind_attrs = true,
+		.of_match_table = rcar_pci_of_match,
 	},
 	.probe = rcar_pci_probe,
 };