ARM: OMAP2+: Add GPMC DT support for Ethernet child nodes

Besides being used to interface with external memory devices,
the General-Purpose Memory Controller can be used to connect
Pseudo-SRAM devices such as ethernet controllers to OMAP2+
processors using the TI GPMC as a data bus.

This patch allows an ethernet chip to be defined as an GPMC
child device node.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Jon Hunter <jon-hunter@ti.com>

Documentation/devicetree/bindings/net/gpmc-eth.txt

+Device tree bindings for Ethernet chip connected to TI GPMC
+
+Besides being used to interface with external memory devices, the
+General-Purpose Memory Controller can be used to connect Pseudo-SRAM devices
+such as ethernet controllers to processors using the TI GPMC as a data bus.
+
+Ethernet controllers connected to TI GPMC are represented as child nodes of
+the GPMC controller with an "ethernet" name.
+
+All timing relevant properties as well as generic GPMC child properties are
+explained in a separate documents. Please refer to
+Documentation/devicetree/bindings/bus/ti-gpmc.txt
+
+For the properties relevant to the ethernet controller connected to the GPMC
+refer to the binding documentation of the device. For example, the documentation
+for the SMSC 911x is Documentation/devicetree/bindings/net/smsc911x.txt
+
+Child nodes need to specify the GPMC bus address width using the "bank-width"
+property but is possible that an ethernet controller also has a property to
+specify the I/O registers address width. Even when the GPMC has a maximum 16-bit
+address width, it supports devices with 32-bit word registers.
+For example with an SMSC LAN911x/912x controller connected to the TI GPMC on an
+OMAP2+ board, "bank-width = <2>;" and "reg-io-width = <4>;".
+
+Required properties:
+- bank-width: 		Address width of the device in bytes. GPMC supports 8-bit
+			and 16-bit devices and so must be either 1 or 2 bytes.
+- compatible:		Compatible string property for the ethernet child device.
+- gpmc,cs-on:		Chip-select assertion time
+- gpmc,cs-rd-off:	Chip-select de-assertion time for reads
+- gpmc,cs-wr-off:	Chip-select de-assertion time for writes
+- gpmc,oe-on:		Output-enable assertion time
+- gpmc,oe-off		Output-enable de-assertion time
+- gpmc,we-on:		Write-enable assertion time
+- gpmc,we-off:		Write-enable de-assertion time
+- gpmc,access:		Start cycle to first data capture (read access)
+- gpmc,rd-cycle:	Total read cycle time
+- gpmc,wr-cycle:	Total write cycle time
+- reg:			Chip-select, base address (relative to chip-select)
+			and size of the memory mapped for the device.
+			Note that base address will be typically 0 as this
+			is the start of the chip-select.
+
+Optional properties:
+- gpmc,XXX		Additional GPMC timings and settings parameters. See
+			Documentation/devicetree/bindings/bus/ti-gpmc.txt
+
+Example:
+
+gpmc: gpmc@6e000000 {
+	compatible = "ti,omap3430-gpmc";
+	ti,hwmods = "gpmc";
+	reg = <0x6e000000 0x1000>;
+	interrupts = <20>;
+	gpmc,num-cs = <8>;
+	gpmc,num-waitpins = <4>;
+	#address-cells = <2>;
+	#size-cells = <1>;
+
+	ranges = <5 0 0x2c000000 0x1000000>;
+
+	ethernet@5,0 {
+		compatible = "smsc,lan9221", "smsc,lan9115";
+		reg = <5 0 0xff>;
+		bank-width = <2>;
+
+		gpmc,mux-add-data;
+		gpmc,cs-on = <0>;
+		gpmc,cs-rd-off = <186>;
+		gpmc,cs-wr-off = <186>;
+		gpmc,adv-on = <12>;
+		gpmc,adv-rd-off = <48>;
+		gpmc,adv-wr-off = <48>;
+		gpmc,oe-on = <54>;
+		gpmc,oe-off = <168>;
+		gpmc,we-on = <54>;
+		gpmc,we-off = <168>;
+		gpmc,rd-cycle = <186>;
+		gpmc,wr-cycle = <186>;
+		gpmc,access = <114>;
+		gpmc,page-burst-access = <6>;
+		gpmc,bus-turnaround = <12>;
+		gpmc,cycle2cycle-delay = <18>;
+		gpmc,wr-data-mux-bus = <90>;
+		gpmc,wr-access = <186>;
+		gpmc,cycle2cycle-samecsen;
+		gpmc,cycle2cycle-diffcsen;
+
+		interrupt-parent = <&gpio6>;
+		interrupts = <16>;
+		vmmc-supply = <&vddvario>;
+		vmmc_aux-supply = <&vdd33a>;
+		reg-io-width = <4>;
+
+		smsc,save-mac-address;
+	};
+};

arch/arm/mach-omap2/gpmc.c

@@ -1544,6 +1544,14 @@ static int gpmc_probe_dt(struct platform_device *pdev)
 		}
 	}
 
+	for_each_node_by_name(child, "ethernet") {
+		ret = gpmc_probe_generic_child(pdev, child);
+		if (ret < 0) {
+			of_node_put(child);
+			return ret;
+		}
+	}
+
 	return 0;
 }
 #else