gpio-rcar: Add DT support

Add DT bindings for the gpio-rcar driver and read the device
configuration from the DT node at probe time if available.

Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt

@@ -0,0 +1,52 @@
+* Renesas R-Car GPIO Controller
+
+Required Properties:
+
+  - compatible: should be one of the following.
+    - "renesas,gpio-r8a7778": for R8A7778 (R-Mobile M1) compatible GPIO controller.
+    - "renesas,gpio-r8a7779": for R8A7779 (R-Car H1) compatible GPIO controller.
+    - "renesas,gpio-r8a7790": for R8A7790 (R-Car H2) compatible GPIO controller.
+    - "renesas,gpio-rcar": for generic R-Car GPIO controller.
+
+  - reg: Base address and length of each memory resource used by the GPIO
+    controller hardware module.
+
+  - interrupt-parent: phandle of the parent interrupt controller.
+  - interrupts: Interrupt specifier for the controllers interrupt.
+
+  - gpio-controller: Marks the device node as a gpio controller.
+  - #gpio-cells: Should be 2. The first cell is the GPIO number and the second
+    cell is used to specify optional parameters as bit flags. Only the GPIO
+    active low flag (bit 0) is currently supported.
+  - gpio-ranges: Range of pins managed by the GPIO controller as a 4-cells
+    tuple using the following syntax.
+
+    <[phandle of the pin controller node]
+     0
+     [index of the first pin]
+     [number of pins]>
+
+Please refer to gpio.txt in this directory for details of the common GPIO
+bindings used by client devices.
+
+Example: R8A7779 (R-Car H1) GPIO controller nodes
+
+	gpio0: gpio@ffc40000 {
+		compatible = "renesas,gpio-r8a7779", "renesas,gpio-rcar";
+		reg = <0xffc40000 0x2c>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 141 0x4>;
+		#gpio-cells = <2>;
+		gpio-controller;
+		gpio-ranges = <&pfc 0 0 32>;
+	};
+	...
+	gpio6: gpio@ffc46000 {
+		compatible = "renesas,gpio-r8a7779", "renesas,gpio-rcar";
+		reg = <0xffc46000 0x2c>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 147 0x4>;
+		#gpio-cells = <2>;
+		gpio-controller;
+		gpio-ranges = <&pfc 0 192 9>;
+	};

drivers/gpio/gpio-rcar.c

@@ -51,6 +51,8 @@ struct gpio_rcar_priv {
 #define FILONOFF 0x28
 #define BOTHEDGE 0x4c
 
+#define RCAR_MAX_GPIO_PER_BANK		32
+
 static inline u32 gpio_rcar_read(struct gpio_rcar_priv *p, int offs)
 {
 	return ioread32(p->base + offs);
@@ -274,9 +276,39 @@ static struct irq_domain_ops gpio_rcar_irq_domain_ops = {
 	.map	= gpio_rcar_irq_domain_map,
 };
 
+static void gpio_rcar_parse_pdata(struct gpio_rcar_priv *p)
+{
+	struct gpio_rcar_config *pdata = p->pdev->dev.platform_data;
+#ifdef CONFIG_OF
+	struct device_node *np = p->pdev->dev.of_node;
+	struct of_phandle_args args;
+	int ret;
+#endif
+
+	if (pdata)
+		p->config = *pdata;
+#ifdef CONFIG_OF
+	else if (np) {
+		ret = of_parse_phandle_with_args(np, "gpio-ranges",
+				"#gpio-range-cells", 0, &args);
+		p->config.number_of_pins = ret == 0 && args.args_count == 3
+					 ? args.args[2]
+					 : RCAR_MAX_GPIO_PER_BANK;
+		p->config.gpio_base = -1;
+	}
+#endif
+
+	if (p->config.number_of_pins == 0 ||
+	    p->config.number_of_pins > RCAR_MAX_GPIO_PER_BANK) {
+		dev_warn(&p->pdev->dev,
+			 "Invalid number of gpio lines %u, using %u\n",
+			 p->config.number_of_pins, RCAR_MAX_GPIO_PER_BANK);
+		p->config.number_of_pins = RCAR_MAX_GPIO_PER_BANK;
+	}
+}
+
 static int gpio_rcar_probe(struct platform_device *pdev)
 {
-	struct gpio_rcar_config *pdata = pdev->dev.platform_data;
 	struct gpio_rcar_priv *p;
 	struct resource *io, *irq;
 	struct gpio_chip *gpio_chip;
@@ -291,14 +323,14 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 		goto err0;
 	}
 
-	/* deal with driver instance configuration */
-	if (pdata)
-		p->config = *pdata;
-
 	p->pdev = pdev;
-	platform_set_drvdata(pdev, p);
 	spin_lock_init(&p->lock);
 
+	/* Get device configuration from DT node or platform data. */
+	gpio_rcar_parse_pdata(p);
+
+	platform_set_drvdata(pdev, p);
+
 	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 
@@ -325,6 +357,7 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 	gpio_chip->set = gpio_rcar_set;
 	gpio_chip->to_irq = gpio_rcar_to_irq;
 	gpio_chip->label = name;
+	gpio_chip->dev = &pdev->dev;
 	gpio_chip->owner = THIS_MODULE;
 	gpio_chip->base = p->config.gpio_base;
 	gpio_chip->ngpio = p->config.number_of_pins;
@@ -371,10 +404,12 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 				 p->config.irq_base, ret);
 	}
 
-	ret = gpiochip_add_pin_range(gpio_chip, p->config.pctl_name, 0,
-				     gpio_chip->base, gpio_chip->ngpio);
-	if (ret < 0)
-		dev_warn(&pdev->dev, "failed to add pin range\n");
+	if (p->config.pctl_name) {
+		ret = gpiochip_add_pin_range(gpio_chip, p->config.pctl_name, 0,
+					     gpio_chip->base, gpio_chip->ngpio);
+		if (ret < 0)
+			dev_warn(&pdev->dev, "failed to add pin range\n");
+	}
 
 	return 0;
 
@@ -397,11 +432,22 @@ static int gpio_rcar_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id gpio_rcar_of_table[] = {
+	{
+		.compatible = "renesas,gpio-rcar",
+	},
+};
+
+MODULE_DEVICE_TABLE(of, gpio_rcar_of_table);
+#endif
+
 static struct platform_driver gpio_rcar_device_driver = {
 	.probe		= gpio_rcar_probe,
 	.remove		= gpio_rcar_remove,
 	.driver		= {
 		.name	= "gpio_rcar",
+		.of_match_table = of_match_ptr(gpio_rcar_of_table),
 	}
 };