[PATCH 2/2] gpiolib-of: ad gpio-export support

[Jean-Christophe PLAGNIOL-VILLARD]

This will allow to export gpios with or without names

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
 Documentation/devicetree/bindings/gpio/gpio.txt |   60 ++++++++++++++++++++++
 drivers/gpio/gpiolib-of.c                       |   61 +++++++++++++++++++++++
 2 files changed, 121 insertions(+)

diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt
index a336287..c2a9024 100644
--- a/Documentation/devicetree/bindings/gpio/gpio.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio.txt
@@ -112,3 +112,63 @@ where,
 
 The pinctrl node must have "#gpio-range-cells" property to show number of
 arguments to pass with phandle from gpio controllers node.
+
+3) gpio-export
+--------------
+
+gpio-export will allow you to automatically export gpio
+
+required properties:
+- compatible: Should be "gpio-export"
+
+in each child node will reprensent a gpio or if no name is specified
+a list of gpio to export
+
+required properties:
+- gpios: gpio to export
+
+optional properties:
+ - gpio-export,name: export name
+ - gpio-export,output: to set the as output with default value
+ 		       if no present gpio as input
+ - pio-export,direction_may_change: boolean to allow the direction to be controllable
+
+Example:
+
+
+gpio_export {
+	compatible = "gpio-export";
+	#size-cells = <0>;
+
+	in {
+		gpio-export,name = "in";
+		gpios = <&pioC 20 0>;
+	};
+
+	out {
+		gpio-export,name = "out";
+		gpio-export,output = <1>;
+		gpio-export,direction_may_change;
+		gpios = <&pioC 21 0>;
+	};
+
+	in_out {
+		gpio-export,name = "in_out";
+		gpio-export,direction_may_change;
+		gpios = <&pioC 21 0>;
+	};
+
+	gpios_in {
+		gpios = <&pioB 0 0
+			 &pioB 3 0
+			 &pioC 4 0>;
+		gpio-export,direction_may_change;
+	};
+
+	gpios_out {
+		gpios = <&pioB 1 0
+			 &pioB 2 0
+			 &pioC 3 0>;
+		gpio-export,output = <1>;
+	};
+};
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index a40cd84..0ab9be4 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -21,6 +21,8 @@
 #include <linux/of_gpio.h>
 #include <linux/pinctrl/pinctrl.h>
 #include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
 
 /* Private data structure for of_gpiochip_find_and_xlate */
 struct gg_data {
@@ -277,3 +279,62 @@ void of_gpiochip_remove(struct gpio_chip *chip)
 	if (chip->of_node)
 		of_node_put(chip->of_node);
 }
+
+static struct of_device_id gpio_export_ids[] = {
+	{ .compatible = "gpio-export" },
+	{ /* sentinel */ }
+};
+
+static int __init of_gpio_export_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct device_node *cnp;
+	u32 val;
+	int nb = 0;
+
+	for_each_child_of_node(np, cnp) {
+		const char *name = NULL;
+		int gpio;
+		bool dmc;
+		int max_gpio = 1;
+		int i;
+
+		of_property_read_string(cnp, "gpio-export,name", &name);
+
+		if (!name)
+			max_gpio = of_gpio_count(cnp);
+
+		for (i = 0; i < max_gpio; i++) {
+			gpio = of_get_gpio(cnp, i);
+			if (devm_gpio_request(&pdev->dev, gpio, name ? name : of_node_full_name(np)))
+				continue;
+
+			if (!of_property_read_u32(cnp, "gpio-export,output", &val))
+				gpio_direction_output(gpio, val);
+			else
+				gpio_direction_input(gpio);
+
+			dmc = of_property_read_bool(np, "gpio-export,direction_may_change");
+			gpio_export_with_name(gpio, dmc, name);
+			nb++;
+		}
+	}
+
+	dev_info(&pdev->dev, "%d gpio(s) exported\n", nb);
+
+	return 0;
+}
+
+static struct platform_driver gpio_export_driver = {
+	.driver		= {
+		.name		= "gpio-export",
+		.owner	= THIS_MODULE,
+		.of_match_table	= of_match_ptr(gpio_export_ids),
+	},
+};
+
+static int __init of_gpio_export_init(void)
+{
+	return platform_driver_probe(&gpio_export_driver, of_gpio_export_probe);
+}
+device_initcall(of_gpio_export_init);
-- 
1.7.10.4