net: ethernet: enc28j60: add device tree support

The following patch adds the required match table for device tree support
(and while at, fix the indent). It's also possible to specify the
MAC address in the DT blob.

Also add the corresponding binding documentation file.

Signed-off-by: Michael Heimpold <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/devicetree/bindings/net/microchip,enc28j60.txt

···
+* Microchip ENC28J60
+
+This is a standalone 10 MBit ethernet controller with SPI interface.
+
+For each device connected to a SPI bus, define a child node within
+the SPI master node.
+
+Required properties:
+- compatible: Should be "microchip,enc28j60"
+- reg: Specify the SPI chip select the ENC28J60 is wired to
+- interrupt-parent: Specify the phandle of the source interrupt, see interrupt
+                    binding documentation for details. Usually this is the GPIO bank
+                    the interrupt line is wired to.
+- interrupts: Specify the interrupt index within the interrupt controller (referred
+              to above in interrupt-parent) and interrupt type. The ENC28J60 natively
+              generates falling edge interrupts, however, additional board logic
+              might invert the signal.
+- pinctrl-names: List of assigned state names, see pinctrl binding documentation.
+- pinctrl-0: List of phandles to configure the GPIO pin used as interrupt line,
+             see also generic and your platform specific pinctrl binding
+             documentation.
+
+Optional properties:
+- spi-max-frequency: Maximum frequency of the SPI bus when accessing the ENC28J60.
+  According to the ENC28J80 datasheet, the chip allows a maximum of 20 MHz, however,
+  board designs may need to limit this value.
+- local-mac-address: See ethernet.txt in the same directory.
+
+
+Example (for NXP i.MX28 with pin control stuff for GPIO irq):
+
+        ssp2: ssp@80014000 {
+                compatible = "fsl,imx28-spi";
+                pinctrl-names = "default";
+                pinctrl-0 = <&spi2_pins_b &spi2_sck_cfg>;
+                status = "okay";
+
+                enc28j60: ethernet@0 {
+                        compatible = "microchip,enc28j60";
+                        pinctrl-names = "default";
+                        pinctrl-0 = <&enc28j60_pins>;
+                        reg = <0>;
+                        interrupt-parent = <&gpio3>;
+                        interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
+                        spi-max-frequency = <12000000>;
+                };
+        };
+
+        pinctrl@80018000 {
+                enc28j60_pins: enc28j60_pins@0 {
+                        reg = <0>;
+                        fsl,pinmux-ids = <
+                                MX28_PAD_AUART0_RTS__GPIO_3_3    /* Interrupt */
+                        >;
+                        fsl,drive-strength = <MXS_DRIVE_4mA>;
+                        fsl,voltage = <MXS_VOLTAGE_HIGH>;
+                        fsl,pull-up = <MXS_PULL_DISABLE>;
+                };
+        };

drivers/net/ethernet/microchip/enc28j60.c

···
 #include <linux/skbuff.h>
 #include <linux/delay.h>
 #include <linux/spi/spi.h>
+#include <linux/of_net.h>
 
 #include "enc28j60_hw.h"
 
 #define DRV_NAME	"enc28j60"
-#define DRV_VERSION	"1.01"
+#define DRV_VERSION	"1.02"
 
 #define SPI_OPLEN	1
 
···
 {
 	struct net_device *dev;
 	struct enc28j60_net *priv;
+	const void *macaddr;
 	int ret = 0;
 
 	if (netif_msg_drv(&debug))
···
 		ret = -EIO;
 		goto error_irq;
 	}
-	eth_hw_addr_random(dev);
+
+	macaddr = of_get_mac_address(spi->dev.of_node);
+	if (macaddr)
+		ether_addr_copy(dev->dev_addr, macaddr);
+	else
+		eth_hw_addr_random(dev);
 	enc28j60_set_hw_macaddr(dev);
 
 	/* Board setup must set the relevant edge trigger type;
···
 	return 0;
 }
 
+static const struct of_device_id enc28j60_dt_ids[] = {
+	{ .compatible = "microchip,enc28j60" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, enc28j60_dt_ids);
+
 static struct spi_driver enc28j60_driver = {
 	.driver = {
-		   .name = DRV_NAME,
+		.name = DRV_NAME,
+		.of_match_table = enc28j60_dt_ids,
 	 },
 	.probe = enc28j60_probe,
 	.remove = enc28j60_remove,