staging: nvec: add device tree support

This adds device tree support to the nvec driver. By using this method
it is no longer necessary to specify platform data through a board
file.
Signed-off-by: Marc Dietrich <marvin24@gmx.de>
Acked-by: Stephen Warren <swarren@nvidia.com>
Cc: Julian Andres Klode <jak@jak-linux.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Documentation/devicetree/bindings/nvec/nvec_nvidia.txt

+NVIDIA compliant embedded controller
+
+Required properties:
+- compatible : should be "nvidia,nvec".
+- reg : the iomem of the i2c slave controller
+- interrupts : the interrupt line of the i2c slave controller
+- clock-frequency : the frequency of the i2c bus
+- gpios : the gpio used for ec request
+- slave-addr: the i2c address of the slave controller

drivers/staging/nvec/nvec.c

@@ -27,6 +27,8 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/irq.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/list.h>
 #include <linux/mfd/core.h>
 #include <linux/mutex.h>
@@ -727,8 +729,24 @@ static int __devinit tegra_nvec_probe(struct platform_device *pdev)
 	}
 	platform_set_drvdata(pdev, nvec);
 	nvec->dev = &pdev->dev;
+
+	if (pdata) {
 		nvec->gpio = pdata->gpio;
 		nvec->i2c_addr = pdata->i2c_addr;
+	} else if (nvec->dev->of_node) {
+		nvec->gpio = of_get_named_gpio(nvec->dev->of_node, "request-gpios", 0);
+		if (nvec->gpio < 0) {
+			dev_err(&pdev->dev, "no gpio specified");
+			goto failed;
+		}
+		if (of_property_read_u32(nvec->dev->of_node, "slave-addr", &nvec->i2c_addr)) {
+			dev_err(&pdev->dev, "no i2c address specified");
+			goto failed;
+		}
+	} else {
+		dev_err(&pdev->dev, "no platform data\n");
+		goto failed;
+	}
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
@@ -893,6 +911,13 @@ static int tegra_nvec_resume(struct platform_device *pdev)
 #define tegra_nvec_resume NULL
 #endif
 
+/* Match table for of_platform binding */
+static const struct of_device_id nvidia_nvec_of_match[] __devinitconst = {
+	{ .compatible = "nvidia,nvec", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, nvidia_nvec_of_match);
+
 static struct platform_driver nvec_device_driver = {
 	.probe   = tegra_nvec_probe,
 	.remove  = __devexit_p(tegra_nvec_remove),
@@ -901,6 +926,7 @@ static struct platform_driver nvec_device_driver = {
 	.driver  = {
 		.name = "nvec",
 		.owner = THIS_MODULE,
+		.of_match_table = nvidia_nvec_of_match,
 	}
 };