1 files changed, 446 insertions, 0 deletions

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
new file mode 100644
index 000000000..a6c67c6b4
--- /dev/null
+++ b/drivers/gpio/gpiolib-of.c
@@ -0,0 +1,446 @@
+/*
+ * 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/err.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_gpio.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/slab.h>
+#include <linux/gpio/machine.h>
+
+#include "gpiolib.h"
+
+/* Private data structure for of_gpiochip_find_and_xlate */
+struct gg_data {
+	enum of_gpio_flags *flags;
+	struct of_phandle_args gpiospec;
+
+	struct gpio_desc *out_gpio;
+};
+
+/* Private function for resolving node pointer to gpio_chip */
+static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
+{
+	struct gg_data *gg_data = data;
+	int ret;
+
+	if ((gc->of_node != gg_data->gpiospec.np) ||
+	    (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
+	    (!gc->of_xlate))
+		return false;
+
+	ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
+	if (ret < 0) {
+		/* We've found a gpio chip, but the translation failed.
+		 * Store translation error in out_gpio.
+		 * Return false to keep looking, as more than one gpio chip
+		 * could be registered per of-node.
+		 */
+		gg_data->out_gpio = ERR_PTR(ret);
+		return false;
+	 }
+
+	gg_data->out_gpio = gpiochip_get_desc(gc, ret);
+	return true;
+}
+
+/**
+ * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for 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 descriptor to use with Linux 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.
+ */
+struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
+		     const char *propname, int index, enum of_gpio_flags *flags)
+{
+	/* Return -EPROBE_DEFER to support probe() functions to be called
+	 * later when the GPIO actually becomes available
+	 */
+	struct gg_data gg_data = {
+		.flags = flags,
+		.out_gpio = ERR_PTR(-EPROBE_DEFER)
+	};
+	int ret;
+
+	/* .of_xlate might decide to not fill in the flags, so clear it. */
+	if (flags)
+		*flags = 0;
+
+	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
+					 &gg_data.gpiospec);
+	if (ret) {
+		pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
+			__func__, propname, np->full_name, index);
+		return ERR_PTR(ret);
+	}
+
+	gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
+
+	of_node_put(gg_data.gpiospec.np);
+	pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
+		 __func__, propname, np->full_name, index,
+		 PTR_ERR_OR_ZERO(gg_data.out_gpio));
+	return gg_data.out_gpio;
+}
+
+int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
+			    int index, enum of_gpio_flags *flags)
+{
+	struct gpio_desc *desc;
+
+	desc = of_get_named_gpiod_flags(np, list_name, index, flags);
+
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+	else
+		return desc_to_gpio(desc);
+}
+EXPORT_SYMBOL(of_get_named_gpio_flags);
+
+/**
+ * of_get_gpio_hog() - Get a GPIO hog descriptor, names and flags for GPIO API
+ * @np:		device node to get GPIO from
+ * @name:	GPIO line name
+ * @lflags:	gpio_lookup_flags - returned from of_find_gpio() or
+ *		of_get_gpio_hog()
+ * @dflags:	gpiod_flags - optional GPIO initialization flags
+ *
+ * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
+ * value on the error condition.
+ */
+static struct gpio_desc *of_get_gpio_hog(struct device_node *np,
+				  const char **name,
+				  enum gpio_lookup_flags *lflags,
+				  enum gpiod_flags *dflags)
+{
+	struct device_node *chip_np;
+	enum of_gpio_flags xlate_flags;
+	struct gpio_desc *desc;
+	struct gg_data gg_data = {
+		.flags = &xlate_flags,
+	};
+	u32 tmp;
+	int i, ret;
+
+	chip_np = np->parent;
+	if (!chip_np)
+		return ERR_PTR(-EINVAL);
+
+	xlate_flags = 0;
+	*lflags = 0;
+	*dflags = 0;
+
+	ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (tmp > MAX_PHANDLE_ARGS)
+		return ERR_PTR(-EINVAL);
+
+	gg_data.gpiospec.args_count = tmp;
+	gg_data.gpiospec.np = chip_np;
+	for (i = 0; i < tmp; i++) {
+		ret = of_property_read_u32_index(np, "gpios", i,
+					   &gg_data.gpiospec.args[i]);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
+	if (!gg_data.out_gpio) {
+		if (np->parent == np)
+			return ERR_PTR(-ENXIO);
+		else
+			return ERR_PTR(-EINVAL);
+	}
+
+	if (xlate_flags & OF_GPIO_ACTIVE_LOW)
+		*lflags |= GPIO_ACTIVE_LOW;
+
+	if (of_property_read_bool(np, "input"))
+		*dflags |= GPIOD_IN;
+	else if (of_property_read_bool(np, "output-low"))
+		*dflags |= GPIOD_OUT_LOW;
+	else if (of_property_read_bool(np, "output-high"))
+		*dflags |= GPIOD_OUT_HIGH;
+	else {
+		pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
+			desc_to_gpio(gg_data.out_gpio), np->name);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (name && of_property_read_string(np, "line-name", name))
+		*name = np->name;
+
+	desc = gg_data.out_gpio;
+
+	return desc;
+}
+
+/**
+ * of_gpiochip_scan_hogs - Scan gpio-controller and apply GPIO hog as requested
+ * @chip:	gpio chip to act on
+ *
+ * This is only used by of_gpiochip_add to request/set GPIO initial
+ * configuration.
+ */
+static void of_gpiochip_scan_hogs(struct gpio_chip *chip)
+{
+	struct gpio_desc *desc = NULL;
+	struct device_node *np;
+	const char *name;
+	enum gpio_lookup_flags lflags;
+	enum gpiod_flags dflags;
+
+	for_each_child_of_node(chip->of_node, np) {
+		if (!of_property_read_bool(np, "gpio-hog"))
+			continue;
+
+		desc = of_get_gpio_hog(np, &name, &lflags, &dflags);
+		if (IS_ERR(desc))
+			continue;
+
+		if (gpiod_hog(desc, name, lflags, dflags))
+			continue;
+	}
+}
+
+/**
+ * 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);
+
+/**
+ * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
+ * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
+ */
+void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
+{
+	struct gpio_chip *gc = &mm_gc->gc;
+
+	if (!mm_gc)
+		return;
+
+	gpiochip_remove(gc);
+	iounmap(mm_gc->regs);
+	kfree(gc->label);
+}
+EXPORT_SYMBOL(of_mm_gpiochip_remove);
+
+#ifdef CONFIG_PINCTRL
+static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
+{
+	struct device_node *np = chip->of_node;
+	struct of_phandle_args pinspec;
+	struct pinctrl_dev *pctldev;
+	int index = 0, ret;
+	const char *name;
+	static const char group_names_propname[] = "gpio-ranges-group-names";
+	struct property *group_names;
+
+	if (!np)
+		return;
+
+	group_names = of_find_property(np, group_names_propname, NULL);
+
+	for (;; index++) {
+		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
+				index, &pinspec);
+		if (ret)
+			break;
+
+		pctldev = of_pinctrl_get(pinspec.np);
+		if (!pctldev)
+			break;
+
+		if (pinspec.args[2]) {
+			if (group_names) {
+				ret = of_property_read_string_index(np,
+						group_names_propname,
+						index, &name);
+				if (strlen(name)) {
+					pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
+						np->full_name);
+					break;
+				}
+			}
+			/* npins != 0: linear range */
+			ret = gpiochip_add_pin_range(chip,
+					pinctrl_dev_get_devname(pctldev),
+					pinspec.args[0],
+					pinspec.args[1],
+					pinspec.args[2]);
+			if (ret)
+				break;
+		} else {
+			/* npins == 0: special range */
+			if (pinspec.args[1]) {
+				pr_err("%s: Illegal gpio-range format.\n",
+					np->full_name);
+				break;
+			}
+
+			if (!group_names) {
+				pr_err("%s: GPIO group range requested but no %s property.\n",
+					np->full_name, group_names_propname);
+				break;
+			}
+
+			ret = of_property_read_string_index(np,
+						group_names_propname,
+						index, &name);
+			if (ret)
+				break;
+
+			if (!strlen(name)) {
+				pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
+				np->full_name);
+				break;
+			}
+
+			ret = gpiochip_add_pingroup_range(chip, pctldev,
+						pinspec.args[0], name);
+			if (ret)
+				break;
+		}
+	}
+}
+
+#else
+static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
+#endif
+
+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_gpiochip_add_pin_range(chip);
+	of_node_get(chip->of_node);
+
+	of_gpiochip_scan_hogs(chip);
+}
+
+void of_gpiochip_remove(struct gpio_chip *chip)
+{
+	gpiochip_remove_pin_ranges(chip);
+	of_node_put(chip->of_node);
+}