gpio: Move DT support code into drivers/gpio

The code in drivers/of/gpio.c isn't shared by any other subsystem since it
is all gpiolib specific.  drivers/gpio is a better place to maintain these
functions.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>

3 files changed, 245 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e6862f13408..1042c3f534f 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -37,6 +37,10 @@ menuconfig GPIOLIB
 
 if GPIOLIB
 
+config OF_GPIO
+	def_bool y
+	depends on OF && !SPARC
+
 config DEBUG_GPIO
 	bool "Debug GPIO calls"
 	depends on DEBUG_KERNEL
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 007f54bd008..1c2f6c0a835 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -3,6 +3,7 @@
 ccflags-$(CONFIG_DEBUG_GPIO)	+= -DDEBUG
 
 obj-$(CONFIG_GPIOLIB)		+= gpiolib.o devres.o
+obj-$(CONFIG_OF_GPIO)		+= gpiolib-of.o
 
 # Device drivers. Generally keep list sorted alphabetically
 obj-$(CONFIG_GPIO_GENERIC)	+= gpio-generic.o
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
new file mode 100644
index 00000000000..bba81216b4d
--- /dev/null
+++ b/drivers/gpio/gpiolib-of.c
@@ -0,0 +1,240 @@
+/*
+ * OF helpers for the GPIO API
+ *
+ * Copyright (c) 2007-2008  MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_gpio.h>
+#include <linux/slab.h>
+
+/**
+ * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
+ * @np:		device node to get GPIO from
+ * @propname:	property name containing gpio specifier(s)
+ * @index:	index of the GPIO
+ * @flags:	a flags pointer to fill in
+ *
+ * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
+ * value on the error condition. If @flags is not NULL the function also fills
+ * in flags for the GPIO.
+ */
+int of_get_named_gpio_flags(struct device_node *np, const char *propname,
+                           int index, enum of_gpio_flags *flags)
+{
+	int ret;
+	struct gpio_chip *gc;
+	struct of_phandle_args gpiospec;
+
+	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
+					 &gpiospec);
+	if (ret) {
+		pr_debug("%s: can't parse gpios property\n", __func__);
+		goto err0;
+	}
+
+	gc = of_node_to_gpiochip(gpiospec.np);
+	if (!gc) {
+		pr_debug("%s: gpio controller %s isn't registered\n",
+			 np->full_name, gpiospec.np->full_name);
+		ret = -ENODEV;
+		goto err1;
+	}
+
+	if (gpiospec.args_count != gc->of_gpio_n_cells) {
+		pr_debug("%s: wrong #gpio-cells for %s\n",
+			 np->full_name, gpiospec.np->full_name);
+		ret = -EINVAL;
+		goto err1;
+	}
+
+	/* .xlate might decide to not fill in the flags, so clear it. */
+	if (flags)
+		*flags = 0;
+
+	ret = gc->of_xlate(gc, &gpiospec, flags);
+	if (ret < 0)
+		goto err1;
+
+	ret += gc->base;
+err1:
+	of_node_put(gpiospec.np);
+err0:
+	pr_debug("%s exited with status %d\n", __func__, ret);
+	return ret;
+}
+EXPORT_SYMBOL(of_get_named_gpio_flags);
+
+/**
+ * of_gpio_named_count - Count GPIOs for a device
+ * @np:		device node to count GPIOs for
+ * @propname:	property name containing gpio specifier(s)
+ *
+ * The function returns the count of GPIOs specified for a node.
+ *
+ * Note that the empty GPIO specifiers counts too. For example,
+ *
+ * gpios = <0
+ *          &pio1 1 2
+ *          0
+ *          &pio2 3 4>;
+ *
+ * defines four GPIOs (so this function will return 4), two of which
+ * are not specified.
+ */
+unsigned int of_gpio_named_count(struct device_node *np, const char* propname)
+{
+	unsigned int cnt = 0;
+
+	do {
+		int ret;
+
+		ret = of_parse_phandle_with_args(np, propname, "#gpio-cells",
+						 cnt, NULL);
+		/* A hole in the gpios = <> counts anyway. */
+		if (ret < 0 && ret != -EEXIST)
+			break;
+	} while (++cnt);
+
+	return cnt;
+}
+EXPORT_SYMBOL(of_gpio_named_count);
+
+/**
+ * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
+ * @gc:		pointer to the gpio_chip structure
+ * @np:		device node of the GPIO chip
+ * @gpio_spec:	gpio specifier as found in the device tree
+ * @flags:	a flags pointer to fill in
+ *
+ * This is simple translation function, suitable for the most 1:1 mapped
+ * gpio chips. This function performs only one sanity check: whether gpio
+ * is less than ngpios (that is specified in the gpio_chip).
+ */
+int of_gpio_simple_xlate(struct gpio_chip *gc,
+			 const struct of_phandle_args *gpiospec, u32 *flags)
+{
+	/*
+	 * We're discouraging gpio_cells < 2, since that way you'll have to
+	 * write your own xlate function (that will have to retrive the GPIO
+	 * number and the flags from a single gpio cell -- this is possible,
+	 * but not recommended).
+	 */
+	if (gc->of_gpio_n_cells < 2) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
+		return -EINVAL;
+
+	if (gpiospec->args[0] > gc->ngpio)
+		return -EINVAL;
+
+	if (flags)
+		*flags = gpiospec->args[1];
+
+	return gpiospec->args[0];
+}
+EXPORT_SYMBOL(of_gpio_simple_xlate);
+
+/**
+ * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
+ * @np:		device node of the GPIO chip
+ * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
+ *
+ * To use this function you should allocate and fill mm_gc with:
+ *
+ * 1) In the gpio_chip structure:
+ *    - all the callbacks
+ *    - of_gpio_n_cells
+ *    - of_xlate callback (optional)
+ *
+ * 3) In the of_mm_gpio_chip structure:
+ *    - save_regs callback (optional)
+ *
+ * If succeeded, this function will map bank's memory and will
+ * do all necessary work for you. Then you'll able to use .regs
+ * to manage GPIOs from the callbacks.
+ */
+int of_mm_gpiochip_add(struct device_node *np,
+		       struct of_mm_gpio_chip *mm_gc)
+{
+	int ret = -ENOMEM;
+	struct gpio_chip *gc = &mm_gc->gc;
+
+	gc->label = kstrdup(np->full_name, GFP_KERNEL);
+	if (!gc->label)
+		goto err0;
+
+	mm_gc->regs = of_iomap(np, 0);
+	if (!mm_gc->regs)
+		goto err1;
+
+	gc->base = -1;
+
+	if (mm_gc->save_regs)
+		mm_gc->save_regs(mm_gc);
+
+	mm_gc->gc.of_node = np;
+
+	ret = gpiochip_add(gc);
+	if (ret)
+		goto err2;
+
+	return 0;
+err2:
+	iounmap(mm_gc->regs);
+err1:
+	kfree(gc->label);
+err0:
+	pr_err("%s: GPIO chip registration failed with status %d\n",
+	       np->full_name, ret);
+	return ret;
+}
+EXPORT_SYMBOL(of_mm_gpiochip_add);
+
+void of_gpiochip_add(struct gpio_chip *chip)
+{
+	if ((!chip->of_node) && (chip->dev))
+		chip->of_node = chip->dev->of_node;
+
+	if (!chip->of_node)
+		return;
+
+	if (!chip->of_xlate) {
+		chip->of_gpio_n_cells = 2;
+		chip->of_xlate = of_gpio_simple_xlate;
+	}
+
+	of_node_get(chip->of_node);
+}
+
+void of_gpiochip_remove(struct gpio_chip *chip)
+{
+	if (chip->of_node)
+		of_node_put(chip->of_node);
+}
+
+/* Private function for resolving node pointer to gpio_chip */
+static int of_gpiochip_is_match(struct gpio_chip *chip, const void *data)
+{
+	return chip->of_node == data;
+}
+
+struct gpio_chip *of_node_to_gpiochip(struct device_node *np)
+{
+	return gpiochip_find(np, of_gpiochip_is_match);
+}