Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1032 insertions, 0 deletions

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
new file mode 100644
index 000000000..0e4e12916
--- /dev/null
+++ b/drivers/gpio/gpiolib-of.c
@@ -0,0 +1,1032 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * OF helpers for the GPIO API
+ *
+ * Copyright (c) 2007-2008  MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ */
+
+#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"
+#include "gpiolib-of.h"
+
+/**
+ * of_gpio_spi_cs_get_count() - special GPIO counting for SPI
+ * @dev:    Consuming device
+ * @con_id: Function within the GPIO consumer
+ *
+ * Some elder GPIO controllers need special quirks. Currently we handle
+ * the Freescale and PPC GPIO controller with bindings that doesn't use the
+ * established "cs-gpios" for chip selects but instead rely on
+ * "gpios" for the chip select lines. If we detect this, we redirect
+ * the counting of "cs-gpios" to count "gpios" transparent to the
+ * driver.
+ */
+static int of_gpio_spi_cs_get_count(struct device *dev, const char *con_id)
+{
+	struct device_node *np = dev->of_node;
+
+	if (!IS_ENABLED(CONFIG_SPI_MASTER))
+		return 0;
+	if (!con_id || strcmp(con_id, "cs"))
+		return 0;
+	if (!of_device_is_compatible(np, "fsl,spi") &&
+	    !of_device_is_compatible(np, "aeroflexgaisler,spictrl") &&
+	    !of_device_is_compatible(np, "ibm,ppc4xx-spi"))
+		return 0;
+	return of_gpio_named_count(np, "gpios");
+}
+
+/*
+ * This is used by external users of of_gpio_count() from <linux/of_gpio.h>
+ *
+ * FIXME: get rid of those external users by converting them to GPIO
+ * descriptors and let them all use gpiod_count()
+ */
+int of_gpio_get_count(struct device *dev, const char *con_id)
+{
+	int ret;
+	char propname[32];
+	unsigned int i;
+
+	ret = of_gpio_spi_cs_get_count(dev, con_id);
+	if (ret > 0)
+		return ret;
+
+	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
+		if (con_id)
+			snprintf(propname, sizeof(propname), "%s-%s",
+				 con_id, gpio_suffixes[i]);
+		else
+			snprintf(propname, sizeof(propname), "%s",
+				 gpio_suffixes[i]);
+
+		ret = of_gpio_named_count(dev->of_node, propname);
+		if (ret > 0)
+			break;
+	}
+	return ret ? ret : -ENOENT;
+}
+
+static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data)
+{
+	struct of_phandle_args *gpiospec = data;
+
+	return chip->gpiodev->dev.of_node == gpiospec->np &&
+				chip->of_xlate &&
+				chip->of_xlate(chip, gpiospec, NULL) >= 0;
+}
+
+static struct gpio_chip *of_find_gpiochip_by_xlate(
+					struct of_phandle_args *gpiospec)
+{
+	return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate);
+}
+
+static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
+					struct of_phandle_args *gpiospec,
+					enum of_gpio_flags *flags)
+{
+	int ret;
+
+	if (chip->of_gpio_n_cells != gpiospec->args_count)
+		return ERR_PTR(-EINVAL);
+
+	ret = chip->of_xlate(chip, gpiospec, flags);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	return gpiochip_get_desc(chip, ret);
+}
+
+/**
+ * of_gpio_need_valid_mask() - figure out if the OF GPIO driver needs
+ * to set the .valid_mask
+ * @gc: the target gpio_chip
+ *
+ * Return: true if the valid mask needs to be set
+ */
+bool of_gpio_need_valid_mask(const struct gpio_chip *gc)
+{
+	int size;
+	const struct device_node *np = gc->of_node;
+
+	size = of_property_count_u32_elems(np,  "gpio-reserved-ranges");
+	if (size > 0 && size % 2 == 0)
+		return true;
+	return false;
+}
+
+static void of_gpio_flags_quirks(const struct device_node *np,
+				 const char *propname,
+				 enum of_gpio_flags *flags,
+				 int index)
+{
+	/*
+	 * Some GPIO fixed regulator quirks.
+	 * Note that active low is the default.
+	 */
+	if (IS_ENABLED(CONFIG_REGULATOR) &&
+	    (of_device_is_compatible(np, "regulator-fixed") ||
+	     of_device_is_compatible(np, "reg-fixed-voltage") ||
+	     (!(strcmp(propname, "enable-gpio") &&
+		strcmp(propname, "enable-gpios")) &&
+	      of_device_is_compatible(np, "regulator-gpio")))) {
+		bool active_low = !of_property_read_bool(np,
+							 "enable-active-high");
+		/*
+		 * The regulator GPIO handles are specified such that the
+		 * presence or absence of "enable-active-high" solely controls
+		 * the polarity of the GPIO line. Any phandle flags must
+		 * be actively ignored.
+		 */
+		if ((*flags & OF_GPIO_ACTIVE_LOW) && !active_low) {
+			pr_warn("%s GPIO handle specifies active low - ignored\n",
+				of_node_full_name(np));
+			*flags &= ~OF_GPIO_ACTIVE_LOW;
+		}
+		if (active_low)
+			*flags |= OF_GPIO_ACTIVE_LOW;
+	}
+	/*
+	 * Legacy open drain handling for fixed voltage regulators.
+	 */
+	if (IS_ENABLED(CONFIG_REGULATOR) &&
+	    of_device_is_compatible(np, "reg-fixed-voltage") &&
+	    of_property_read_bool(np, "gpio-open-drain")) {
+		*flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN);
+		pr_info("%s uses legacy open drain flag - update the DTS if you can\n",
+			of_node_full_name(np));
+	}
+
+	/*
+	 * Legacy handling of SPI active high chip select. If we have a
+	 * property named "cs-gpios" we need to inspect the child node
+	 * to determine if the flags should have inverted semantics.
+	 */
+	if (IS_ENABLED(CONFIG_SPI_MASTER) && !strcmp(propname, "cs-gpios") &&
+	    of_property_read_bool(np, "cs-gpios")) {
+		struct device_node *child;
+		u32 cs;
+		int ret;
+
+		for_each_child_of_node(np, child) {
+			ret = of_property_read_u32(child, "reg", &cs);
+			if (ret)
+				continue;
+			if (cs == index) {
+				/*
+				 * SPI children have active low chip selects
+				 * by default. This can be specified negatively
+				 * by just omitting "spi-cs-high" in the
+				 * device node, or actively by tagging on
+				 * GPIO_ACTIVE_LOW as flag in the device
+				 * tree. If the line is simultaneously
+				 * tagged as active low in the device tree
+				 * and has the "spi-cs-high" set, we get a
+				 * conflict and the "spi-cs-high" flag will
+				 * take precedence.
+				 */
+				if (of_property_read_bool(child, "spi-cs-high")) {
+					if (*flags & OF_GPIO_ACTIVE_LOW) {
+						pr_warn("%s GPIO handle specifies active low - ignored\n",
+							of_node_full_name(child));
+						*flags &= ~OF_GPIO_ACTIVE_LOW;
+					}
+				} else {
+					if (!(*flags & OF_GPIO_ACTIVE_LOW))
+						pr_info("%s enforce active low on chipselect handle\n",
+							of_node_full_name(child));
+					*flags |= OF_GPIO_ACTIVE_LOW;
+				}
+				of_node_put(child);
+				break;
+			}
+		}
+	}
+
+	/* Legacy handling of stmmac's active-low PHY reset line */
+	if (IS_ENABLED(CONFIG_STMMAC_ETH) &&
+	    !strcmp(propname, "snps,reset-gpio") &&
+	    of_property_read_bool(np, "snps,reset-active-low"))
+		*flags |= OF_GPIO_ACTIVE_LOW;
+}
+
+/**
+ * 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.
+ */
+static struct gpio_desc *of_get_named_gpiod_flags(const struct device_node *np,
+		     const char *propname, int index, enum of_gpio_flags *flags)
+{
+	struct of_phandle_args gpiospec;
+	struct gpio_chip *chip;
+	struct gpio_desc *desc;
+	int ret;
+
+	ret = of_parse_phandle_with_args_map(np, propname, "gpio", index,
+					     &gpiospec);
+	if (ret) {
+		pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n",
+			__func__, propname, np, index);
+		return ERR_PTR(ret);
+	}
+
+	chip = of_find_gpiochip_by_xlate(&gpiospec);
+	if (!chip) {
+		desc = ERR_PTR(-EPROBE_DEFER);
+		goto out;
+	}
+
+	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
+	if (IS_ERR(desc))
+		goto out;
+
+	if (flags)
+		of_gpio_flags_quirks(np, propname, flags, index);
+
+	pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n",
+		 __func__, propname, np, index,
+		 PTR_ERR_OR_ZERO(desc));
+
+out:
+	of_node_put(gpiospec.np);
+
+	return desc;
+}
+
+int of_get_named_gpio_flags(const 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_GPL(of_get_named_gpio_flags);
+
+/* Converts gpio_lookup_flags into bitmask of GPIO_* values */
+static unsigned long of_convert_gpio_flags(enum of_gpio_flags flags)
+{
+	unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
+
+	if (flags & OF_GPIO_ACTIVE_LOW)
+		lflags |= GPIO_ACTIVE_LOW;
+
+	if (flags & OF_GPIO_SINGLE_ENDED) {
+		if (flags & OF_GPIO_OPEN_DRAIN)
+			lflags |= GPIO_OPEN_DRAIN;
+		else
+			lflags |= GPIO_OPEN_SOURCE;
+	}
+
+	if (flags & OF_GPIO_TRANSITORY)
+		lflags |= GPIO_TRANSITORY;
+
+	if (flags & OF_GPIO_PULL_UP)
+		lflags |= GPIO_PULL_UP;
+
+	if (flags & OF_GPIO_PULL_DOWN)
+		lflags |= GPIO_PULL_DOWN;
+
+	if (flags & OF_GPIO_PULL_DISABLE)
+		lflags |= GPIO_PULL_DISABLE;
+
+	return lflags;
+}
+
+/**
+ * gpiod_get_from_of_node() - obtain a GPIO from an OF node
+ * @node:	handle of the OF node
+ * @propname:	name of the DT property representing the GPIO
+ * @index:	index of the GPIO to obtain for the consumer
+ * @dflags:	GPIO initialization flags
+ * @label:	label to attach to the requested GPIO
+ *
+ * Returns:
+ * On successful request the GPIO pin is configured in accordance with
+ * provided @dflags.
+ *
+ * In case of error an ERR_PTR() is returned.
+ */
+struct gpio_desc *gpiod_get_from_of_node(const struct device_node *node,
+					 const char *propname, int index,
+					 enum gpiod_flags dflags,
+					 const char *label)
+{
+	unsigned long lflags;
+	struct gpio_desc *desc;
+	enum of_gpio_flags of_flags;
+	int ret;
+
+	desc = of_get_named_gpiod_flags(node, propname, index, &of_flags);
+	if (!desc || IS_ERR(desc))
+		return desc;
+
+	ret = gpiod_request(desc, label);
+	if (ret == -EBUSY && (dflags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
+		return desc;
+	if (ret)
+		return ERR_PTR(ret);
+
+	lflags = of_convert_gpio_flags(of_flags);
+
+	ret = gpiod_configure_flags(desc, propname, lflags, dflags);
+	if (ret < 0) {
+		gpiod_put(desc);
+		return ERR_PTR(ret);
+	}
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_from_of_node);
+
+/*
+ * The SPI GPIO bindings happened before we managed to establish that GPIO
+ * properties should be named "foo-gpios" so we have this special kludge for
+ * them.
+ */
+static struct gpio_desc *of_find_spi_gpio(struct device_node *np,
+					  const char *con_id,
+					  unsigned int idx,
+					  enum of_gpio_flags *of_flags)
+{
+	char prop_name[32]; /* 32 is max size of property name */
+
+	/*
+	 * Hopefully the compiler stubs the rest of the function if this
+	 * is false.
+	 */
+	if (!IS_ENABLED(CONFIG_SPI_MASTER))
+		return ERR_PTR(-ENOENT);
+
+	/* Allow this specifically for "spi-gpio" devices */
+	if (!of_device_is_compatible(np, "spi-gpio") || !con_id)
+		return ERR_PTR(-ENOENT);
+
+	/* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */
+	snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id);
+
+	return of_get_named_gpiod_flags(np, prop_name, idx, of_flags);
+}
+
+/*
+ * The old Freescale bindings use simply "gpios" as name for the chip select
+ * lines rather than "cs-gpios" like all other SPI hardware. Account for this
+ * with a special quirk.
+ */
+static struct gpio_desc *of_find_spi_cs_gpio(struct device_node *np,
+					     const char *con_id,
+					     unsigned int idx,
+					     enum of_gpio_flags *of_flags)
+{
+	if (!IS_ENABLED(CONFIG_SPI_MASTER))
+		return ERR_PTR(-ENOENT);
+
+	/* Allow this specifically for Freescale and PPC devices */
+	if (!of_device_is_compatible(np, "fsl,spi") &&
+	    !of_device_is_compatible(np, "aeroflexgaisler,spictrl") &&
+	    !of_device_is_compatible(np, "ibm,ppc4xx-spi"))
+		return ERR_PTR(-ENOENT);
+	/* Allow only if asking for "cs-gpios" */
+	if (!con_id || strcmp(con_id, "cs"))
+		return ERR_PTR(-ENOENT);
+
+	/*
+	 * While all other SPI controllers use "cs-gpios" the Freescale
+	 * uses just "gpios" so translate to that when "cs-gpios" is
+	 * requested.
+	 */
+	return of_get_named_gpiod_flags(np, "gpios", idx, of_flags);
+}
+
+/*
+ * Some regulator bindings happened before we managed to establish that GPIO
+ * properties should be named "foo-gpios" so we have this special kludge for
+ * them.
+ */
+static struct gpio_desc *of_find_regulator_gpio(struct device_node *np,
+						const char *con_id,
+						unsigned int idx,
+						enum of_gpio_flags *of_flags)
+{
+	/* These are the connection IDs we accept as legacy GPIO phandles */
+	const char *whitelist[] = {
+		"wlf,ldoena", /* Arizona */
+		"wlf,ldo1ena", /* WM8994 */
+		"wlf,ldo2ena", /* WM8994 */
+	};
+	int i;
+
+	if (!IS_ENABLED(CONFIG_REGULATOR))
+		return ERR_PTR(-ENOENT);
+
+	if (!con_id)
+		return ERR_PTR(-ENOENT);
+
+	i = match_string(whitelist, ARRAY_SIZE(whitelist), con_id);
+	if (i < 0)
+		return ERR_PTR(-ENOENT);
+
+	return of_get_named_gpiod_flags(np, con_id, idx, of_flags);
+}
+
+static struct gpio_desc *of_find_arizona_gpio(struct device_node *np,
+					      const char *con_id,
+					      unsigned int idx,
+					      enum of_gpio_flags *of_flags)
+{
+	if (!IS_ENABLED(CONFIG_MFD_ARIZONA))
+		return ERR_PTR(-ENOENT);
+
+	if (!con_id || strcmp(con_id, "wlf,reset"))
+		return ERR_PTR(-ENOENT);
+
+	return of_get_named_gpiod_flags(np, con_id, idx, of_flags);
+}
+
+static struct gpio_desc *of_find_usb_gpio(struct device_node *np,
+					  const char *con_id,
+					  unsigned int idx,
+					  enum of_gpio_flags *of_flags)
+{
+	/*
+	 * Currently this USB quirk is only for the Fairchild FUSB302 host
+	 * which is using an undocumented DT GPIO line named "fcs,int_n"
+	 * without the compulsory "-gpios" suffix.
+	 */
+	if (!IS_ENABLED(CONFIG_TYPEC_FUSB302))
+		return ERR_PTR(-ENOENT);
+
+	if (!con_id || strcmp(con_id, "fcs,int_n"))
+		return ERR_PTR(-ENOENT);
+
+	return of_get_named_gpiod_flags(np, con_id, idx, of_flags);
+}
+
+typedef struct gpio_desc *(*of_find_gpio_quirk)(struct device_node *np,
+						const char *con_id,
+						unsigned int idx,
+						enum of_gpio_flags *of_flags);
+static const of_find_gpio_quirk of_find_gpio_quirks[] = {
+	of_find_spi_gpio,
+	of_find_spi_cs_gpio,
+	of_find_regulator_gpio,
+	of_find_arizona_gpio,
+	of_find_usb_gpio,
+	NULL
+};
+
+struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
+			       unsigned int idx, unsigned long *flags)
+{
+	char prop_name[32]; /* 32 is max size of property name */
+	enum of_gpio_flags of_flags;
+	const of_find_gpio_quirk *q;
+	struct gpio_desc *desc;
+	unsigned int i;
+
+	/* Try GPIO property "foo-gpios" and "foo-gpio" */
+	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
+		if (con_id)
+			snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
+				 gpio_suffixes[i]);
+		else
+			snprintf(prop_name, sizeof(prop_name), "%s",
+				 gpio_suffixes[i]);
+
+		desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
+						&of_flags);
+
+		if (!gpiod_not_found(desc))
+			break;
+	}
+
+	/* Properly named GPIO was not found, try workarounds */
+	for (q = of_find_gpio_quirks; gpiod_not_found(desc) && *q; q++)
+		desc = (*q)(dev->of_node, con_id, idx, &of_flags);
+
+	if (IS_ERR(desc))
+		return desc;
+
+	*flags = of_convert_gpio_flags(of_flags);
+
+	return desc;
+}
+
+/**
+ * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
+ * @np:		device node to get GPIO from
+ * @chip:	GPIO chip whose hog is parsed
+ * @idx:	Index of the GPIO to parse
+ * @name:	GPIO line name
+ * @lflags:	bitmask of gpio_lookup_flags GPIO_* values - returned from
+ *		of_find_gpio() or of_parse_own_gpio()
+ * @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_parse_own_gpio(struct device_node *np,
+					   struct gpio_chip *chip,
+					   unsigned int idx, const char **name,
+					   unsigned long *lflags,
+					   enum gpiod_flags *dflags)
+{
+	struct device_node *chip_np;
+	enum of_gpio_flags xlate_flags;
+	struct of_phandle_args gpiospec;
+	struct gpio_desc *desc;
+	unsigned int i;
+	u32 tmp;
+	int ret;
+
+	chip_np = chip->of_node;
+	if (!chip_np)
+		return ERR_PTR(-EINVAL);
+
+	xlate_flags = 0;
+	*lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
+	*dflags = GPIOD_ASIS;
+
+	ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
+	if (ret)
+		return ERR_PTR(ret);
+
+	gpiospec.np = chip_np;
+	gpiospec.args_count = tmp;
+
+	for (i = 0; i < tmp; i++) {
+		ret = of_property_read_u32_index(np, "gpios", idx * tmp + i,
+						 &gpiospec.args[i]);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
+	if (IS_ERR(desc))
+		return desc;
+
+	*lflags = of_convert_gpio_flags(xlate_flags);
+
+	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 (%pOFn): no hogging state specified, bailing out\n",
+			desc_to_gpio(desc), np);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (name && of_property_read_string(np, "line-name", name))
+		*name = np->name;
+
+	return desc;
+}
+
+/**
+ * of_gpiochip_add_hog - Add all hogs in a hog device node
+ * @chip:	gpio chip to act on
+ * @hog:	device node describing the hogs
+ *
+ * Returns error if it fails otherwise 0 on success.
+ */
+static int of_gpiochip_add_hog(struct gpio_chip *chip, struct device_node *hog)
+{
+	enum gpiod_flags dflags;
+	struct gpio_desc *desc;
+	unsigned long lflags;
+	const char *name;
+	unsigned int i;
+	int ret;
+
+	for (i = 0;; i++) {
+		desc = of_parse_own_gpio(hog, chip, i, &name, &lflags, &dflags);
+		if (IS_ERR(desc))
+			break;
+
+		ret = gpiod_hog(desc, name, lflags, dflags);
+		if (ret < 0)
+			return ret;
+
+#ifdef CONFIG_OF_DYNAMIC
+		desc->hog = hog;
+#endif
+	}
+
+	return 0;
+}
+
+/**
+ * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
+ * @chip:	gpio chip to act on
+ *
+ * This is only used by of_gpiochip_add to request/set GPIO initial
+ * configuration.
+ * It returns error if it fails otherwise 0 on success.
+ */
+static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
+{
+	struct device_node *np;
+	int ret;
+
+	for_each_available_child_of_node(chip->of_node, np) {
+		if (!of_property_read_bool(np, "gpio-hog"))
+			continue;
+
+		ret = of_gpiochip_add_hog(chip, np);
+		if (ret < 0) {
+			of_node_put(np);
+			return ret;
+		}
+
+		of_node_set_flag(np, OF_POPULATED);
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_OF_DYNAMIC
+/**
+ * of_gpiochip_remove_hog - Remove all hogs in a hog device node
+ * @chip:	gpio chip to act on
+ * @hog:	device node describing the hogs
+ */
+static void of_gpiochip_remove_hog(struct gpio_chip *chip,
+				   struct device_node *hog)
+{
+	struct gpio_desc *desc;
+
+	for_each_gpio_desc_with_flag(chip, desc, FLAG_IS_HOGGED)
+		if (desc->hog == hog)
+			gpiochip_free_own_desc(desc);
+}
+
+static int of_gpiochip_match_node(struct gpio_chip *chip, void *data)
+{
+	return device_match_of_node(&chip->gpiodev->dev, data);
+}
+
+static struct gpio_chip *of_find_gpiochip_by_node(struct device_node *np)
+{
+	return gpiochip_find(np, of_gpiochip_match_node);
+}
+
+static int of_gpio_notify(struct notifier_block *nb, unsigned long action,
+			  void *arg)
+{
+	struct of_reconfig_data *rd = arg;
+	struct gpio_chip *chip;
+	int ret;
+
+	/*
+	 * This only supports adding and removing complete gpio-hog nodes.
+	 * Modifying an existing gpio-hog node is not supported (except for
+	 * changing its "status" property, which is treated the same as
+	 * addition/removal).
+	 */
+	switch (of_reconfig_get_state_change(action, arg)) {
+	case OF_RECONFIG_CHANGE_ADD:
+		if (!of_property_read_bool(rd->dn, "gpio-hog"))
+			return NOTIFY_OK;	/* not for us */
+
+		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED))
+			return NOTIFY_OK;
+
+		chip = of_find_gpiochip_by_node(rd->dn->parent);
+		if (chip == NULL)
+			return NOTIFY_OK;	/* not for us */
+
+		ret = of_gpiochip_add_hog(chip, rd->dn);
+		if (ret < 0) {
+			pr_err("%s: failed to add hogs for %pOF\n", __func__,
+			       rd->dn);
+			of_node_clear_flag(rd->dn, OF_POPULATED);
+			return notifier_from_errno(ret);
+		}
+		break;
+
+	case OF_RECONFIG_CHANGE_REMOVE:
+		if (!of_node_check_flag(rd->dn, OF_POPULATED))
+			return NOTIFY_OK;	/* already depopulated */
+
+		chip = of_find_gpiochip_by_node(rd->dn->parent);
+		if (chip == NULL)
+			return NOTIFY_OK;	/* not for us */
+
+		of_gpiochip_remove_hog(chip, rd->dn);
+		of_node_clear_flag(rd->dn, OF_POPULATED);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+struct notifier_block gpio_of_notifier = {
+	.notifier_call = of_gpio_notify,
+};
+#endif /* CONFIG_OF_DYNAMIC */
+
+/**
+ * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags
+ * @gc:		pointer to the gpio_chip structure
+ * @gpiospec:	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).
+ */
+static 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 retrieve 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];
+}
+
+/**
+ * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
+ * @np:		device node of the GPIO chip
+ * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
+ * @data:	driver data to store in the struct gpio_chip
+ *
+ * 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_data(struct device_node *np,
+			    struct of_mm_gpio_chip *mm_gc,
+			    void *data)
+{
+	int ret = -ENOMEM;
+	struct gpio_chip *gc = &mm_gc->gc;
+
+	gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
+	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);
+
+	of_node_put(mm_gc->gc.of_node);
+	mm_gc->gc.of_node = of_node_get(np);
+
+	ret = gpiochip_add_data(gc, data);
+	if (ret)
+		goto err2;
+
+	return 0;
+err2:
+	of_node_put(np);
+	iounmap(mm_gc->regs);
+err1:
+	kfree(gc->label);
+err0:
+	pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_mm_gpiochip_add_data);
+
+/**
+ * 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_GPL(of_mm_gpiochip_remove);
+
+static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)
+{
+	int len, i;
+	u32 start, count;
+	struct device_node *np = chip->of_node;
+
+	len = of_property_count_u32_elems(np,  "gpio-reserved-ranges");
+	if (len < 0 || len % 2 != 0)
+		return;
+
+	for (i = 0; i < len; i += 2) {
+		of_property_read_u32_index(np, "gpio-reserved-ranges",
+					   i, &start);
+		of_property_read_u32_index(np, "gpio-reserved-ranges",
+					   i + 1, &count);
+		if (start >= chip->ngpio || start + count > chip->ngpio)
+			continue;
+
+		bitmap_clear(chip->valid_mask, start, count);
+	}
+};
+
+#ifdef CONFIG_PINCTRL
+static int 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 0;
+
+	if (!of_property_read_bool(np, "gpio-ranges") &&
+	    chip->of_gpio_ranges_fallback) {
+		return chip->of_gpio_ranges_fallback(chip, np);
+	}
+
+	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);
+		of_node_put(pinspec.np);
+		if (!pctldev)
+			return -EPROBE_DEFER;
+
+		if (pinspec.args[2]) {
+			if (group_names) {
+				of_property_read_string_index(np,
+						group_names_propname,
+						index, &name);
+				if (strlen(name)) {
+					pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n",
+						np);
+					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)
+				return ret;
+		} else {
+			/* npins == 0: special range */
+			if (pinspec.args[1]) {
+				pr_err("%pOF: Illegal gpio-range format.\n",
+					np);
+				break;
+			}
+
+			if (!group_names) {
+				pr_err("%pOF: GPIO group range requested but no %s property.\n",
+					np, group_names_propname);
+				break;
+			}
+
+			ret = of_property_read_string_index(np,
+						group_names_propname,
+						index, &name);
+			if (ret)
+				break;
+
+			if (!strlen(name)) {
+				pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n",
+				np);
+				break;
+			}
+
+			ret = gpiochip_add_pingroup_range(chip, pctldev,
+						pinspec.args[0], name);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+#else
+static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
+#endif
+
+int of_gpiochip_add(struct gpio_chip *chip)
+{
+	int ret;
+
+	if (!chip->of_node)
+		return 0;
+
+	if (!chip->of_xlate) {
+		chip->of_gpio_n_cells = 2;
+		chip->of_xlate = of_gpio_simple_xlate;
+	}
+
+	if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
+		return -EINVAL;
+
+	of_gpiochip_init_valid_mask(chip);
+
+	ret = of_gpiochip_add_pin_range(chip);
+	if (ret)
+		return ret;
+
+	of_node_get(chip->of_node);
+
+	ret = of_gpiochip_scan_gpios(chip);
+	if (ret)
+		of_node_put(chip->of_node);
+
+	return ret;
+}
+
+void of_gpiochip_remove(struct gpio_chip *chip)
+{
+	of_node_put(chip->of_node);
+}
+
+void of_gpio_dev_init(struct gpio_chip *gc, struct gpio_device *gdev)
+{
+	/* Set default OF node to parent's one if present */
+	if (gc->parent)
+		gdev->dev.of_node = gc->parent->of_node;
+
+	if (gc->fwnode)
+		gc->of_node = to_of_node(gc->fwnode);
+
+	/* If the gpiochip has an assigned OF node this takes precedence */
+	if (gc->of_node)
+		gdev->dev.of_node = gc->of_node;
+	else
+		gc->of_node = gdev->dev.of_node;
+}