i2c-designware: add OF binding support

Add of_match_table and DT style i2c registration to designware i2c
driver.

Refactored for pci/plat split by Dirk Brandewie.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>

Documentation/devicetree/bindings/i2c/i2c-designware.txt

+* Synopsys DesignWare I2C
+
+Required properties :
+
+ - compatible : should be "snps,designware-i2c"
+ - reg : Offset and length of the register set for the device
+ - interrupts : <IRQ> where IRQ is the interrupt number.
+
+Recommended properties :
+
+ - clock-frequency : desired I2C bus clock frequency in Hz.
+
+Example :
+
+	i2c@f0000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "snps,designware-i2c";
+		reg = <0xf0000 0x1000>;
+		interrupts = <11>;
+		clock-frequency = <400000>;
+	};

drivers/i2c/busses/i2c-designware-platdrv.c

@@ -34,6 +34,7 @@
 #include <linux/sched.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
+#include <linux/of_i2c.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/slab.h>
@@ -137,6 +138,7 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
 			sizeof(adap->name));
 	adap->algo = &i2c_dw_algo;
 	adap->dev.parent = &pdev->dev;
+	adap->dev.of_node = pdev->dev.of_node;
 
 	adap->nr = pdev->id;
 	r = i2c_add_numbered_adapter(adap);
@@ -144,6 +146,7 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "failure adding adapter\n");
 		goto err_free_irq;
 	}
+	of_i2c_register_devices(adap);
 
 	return 0;
 
@@ -187,6 +190,14 @@ static int __devexit dw_i2c_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id dw_i2c_of_match[] = {
+	{ .compatible = "snps,designware-i2c", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
+#endif
+
 /* work with hotplug and coldplug */
 MODULE_ALIAS("platform:i2c_designware");
 
@@ -195,6 +206,7 @@ static struct platform_driver dw_i2c_driver = {
 	.driver		= {
 		.name	= "i2c_designware",
 		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(dw_i2c_of_match),
 	},
 };