gpio/mxc: add device tree probe support

The patch adds device tree probe support for gpio-mxc driver.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Documentation/devicetree/bindings/gpio/fsl-imx-gpio.txt

+* Freescale i.MX/MXC GPIO controller
+
+Required properties:
+- compatible : Should be "fsl,<soc>-gpio"
+- reg : Address and length of the register set for the device
+- interrupts : Should be the port interrupt shared by all 32 pins, if
+  one number.  If two numbers, the first one is the interrupt shared
+  by low 16 pins and the second one is for high 16 pins.
+- gpio-controller : Marks the device node as a gpio controller.
+- #gpio-cells : Should be two.  The first cell is the pin number and
+  the second cell is used to specify optional parameters (currently
+  unused).
+
+Example:
+
+gpio0: gpio@73f84000 {
+	compatible = "fsl,imx51-gpio", "fsl,imx31-gpio";
+	reg = <0x73f84000 0x4000>;
+	interrupts = <50 51>;
+	gpio-controller;
+	#gpio-cells = <2>;
+};

drivers/gpio/gpio-mxc.c

@@ -27,6 +27,8 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/basic_mmio_gpio.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include <asm-generic/bug.h>
 
 enum mxc_gpio_hwtype {
@@ -120,6 +122,13 @@ static struct platform_device_id mxc_gpio_devtype[] = {
 	}
 };
 
+static const struct of_device_id mxc_gpio_dt_ids[] = {
+	{ .compatible = "fsl,imx1-gpio", .data = &mxc_gpio_devtype[IMX1_GPIO], },
+	{ .compatible = "fsl,imx21-gpio", .data = &mxc_gpio_devtype[IMX21_GPIO], },
+	{ .compatible = "fsl,imx31-gpio", .data = &mxc_gpio_devtype[IMX31_GPIO], },
+	{ /* sentinel */ }
+};
+
 /*
  * MX2 has one interrupt *for all* gpio ports. The list is used
  * to save the references to all ports, so that mx2_gpio_irq_handler
@@ -302,7 +311,13 @@ static void __init mxc_gpio_init_gc(struct mxc_gpio_port *port)
 
 static void __devinit mxc_gpio_get_hw(struct platform_device *pdev)
 {
-	enum mxc_gpio_hwtype hwtype = pdev->id_entry->driver_data;
+	const struct of_device_id *of_id =
+			of_match_device(mxc_gpio_dt_ids, &pdev->dev);
+	enum mxc_gpio_hwtype hwtype;
+
+	if (of_id)
+		pdev->id_entry = of_id->data;
+	hwtype = pdev->id_entry->driver_data;
 
 	if (mxc_gpio_hwtype) {
 		/*
@@ -324,6 +339,7 @@ static void __devinit mxc_gpio_get_hw(struct platform_device *pdev)
 
 static int __devinit mxc_gpio_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct mxc_gpio_port *port;
 	struct resource *iores;
 	int err;
@@ -334,8 +350,6 @@ static int __devinit mxc_gpio_probe(struct platform_device *pdev)
 	if (!port)
 		return -ENOMEM;
 
-	port->virtual_irq_start = MXC_GPIO_IRQ_START + pdev->id * 32;
-
 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!iores) {
 		err = -ENODEV;
@@ -365,9 +379,6 @@ static int __devinit mxc_gpio_probe(struct platform_device *pdev)
 	writel(0, port->base + GPIO_IMR);
 	writel(~0, port->base + GPIO_ISR);
 
-	/* gpio-mxc can be a generic irq chip */
-	mxc_gpio_init_gc(port);
-
 	if (mxc_gpio_hwtype == IMX21_GPIO) {
 		/* setup one handler for all GPIO interrupts */
 		if (pdev->id == 0)
@@ -400,6 +411,16 @@ static int __devinit mxc_gpio_probe(struct platform_device *pdev)
 	if (err)
 		goto out_bgpio_remove;
 
+	/*
+	 * In dt case, we use gpio number range dynamically
+	 * allocated by gpio core.
+	 */
+	port->virtual_irq_start = MXC_GPIO_IRQ_START + (np ? port->bgc.gc.base :
+							     pdev->id * 32);
+
+	/* gpio-mxc can be a generic irq chip */
+	mxc_gpio_init_gc(port);
+
 	list_add_tail(&port->node, &mxc_gpio_ports);
 
 	return 0;
@@ -420,6 +441,7 @@ static struct platform_driver mxc_gpio_driver = {
 	.driver		= {
 		.name	= "gpio-mxc",
 		.owner	= THIS_MODULE,
+		.of_match_table = mxc_gpio_dt_ids,
 	},
 	.probe		= mxc_gpio_probe,
 	.id_table	= mxc_gpio_devtype,