Initial import

1 files changed, 2377 insertions, 0 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
new file mode 100644
index 000000000..6bc612b8a
--- /dev/null
+++ b/drivers/gpio/gpiolib.c
@@ -0,0 +1,2377 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/machine.h>
+
+#include "gpiolib.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/gpio.h>
+
+/* Implementation infrastructure for GPIO interfaces.
+ *
+ * The GPIO programming interface allows for inlining speed-critical
+ * get/set operations for common cases, so that access to SOC-integrated
+ * GPIOs can sometimes cost only an instruction or two per bit.
+ */
+
+
+/* When debugging, extend minimal trust to callers and platform code.
+ * Also emit diagnostic messages that may help initial bringup, when
+ * board setup or driver bugs are most common.
+ *
+ * Otherwise, minimize overhead in what may be bitbanging codepaths.
+ */
+#ifdef	DEBUG
+#define	extra_checks	1
+#else
+#define	extra_checks	0
+#endif
+
+/* gpio_lock prevents conflicts during gpio_desc[] table updates.
+ * While any GPIO is requested, its gpio_chip is not removable;
+ * each GPIO's "requested" flag serves as a lock and refcount.
+ */
+DEFINE_SPINLOCK(gpio_lock);
+
+#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
+
+static DEFINE_MUTEX(gpio_lookup_lock);
+static LIST_HEAD(gpio_lookup_list);
+LIST_HEAD(gpio_chips);
+
+
+static void gpiochip_free_hogs(struct gpio_chip *chip);
+static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);
+
+
+static inline void desc_set_label(struct gpio_desc *d, const char *label)
+{
+	d->label = label;
+}
+
+/**
+ * Convert a GPIO number to its descriptor
+ */
+struct gpio_desc *gpio_to_desc(unsigned gpio)
+{
+	struct gpio_chip *chip;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpio_lock, flags);
+
+	list_for_each_entry(chip, &gpio_chips, list) {
+		if (chip->base <= gpio && chip->base + chip->ngpio > gpio) {
+			spin_unlock_irqrestore(&gpio_lock, flags);
+			return &chip->desc[gpio - chip->base];
+		}
+	}
+
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	if (!gpio_is_valid(gpio))
+		WARN(1, "invalid GPIO %d\n", gpio);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(gpio_to_desc);
+
+/**
+ * Get the GPIO descriptor corresponding to the given hw number for this chip.
+ */
+struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
+				    u16 hwnum)
+{
+	if (hwnum >= chip->ngpio)
+		return ERR_PTR(-EINVAL);
+
+	return &chip->desc[hwnum];
+}
+
+/**
+ * Convert a GPIO descriptor to the integer namespace.
+ * This should disappear in the future but is needed since we still
+ * use GPIO numbers for error messages and sysfs nodes
+ */
+int desc_to_gpio(const struct gpio_desc *desc)
+{
+	return desc->chip->base + (desc - &desc->chip->desc[0]);
+}
+EXPORT_SYMBOL_GPL(desc_to_gpio);
+
+
+/**
+ * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
+ * @desc:	descriptor to return the chip of
+ */
+struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
+{
+	return desc ? desc->chip : NULL;
+}
+EXPORT_SYMBOL_GPL(gpiod_to_chip);
+
+/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
+static int gpiochip_find_base(int ngpio)
+{
+	struct gpio_chip *chip;
+	int base = ARCH_NR_GPIOS - ngpio;
+
+	list_for_each_entry_reverse(chip, &gpio_chips, list) {
+		/* found a free space? */
+		if (chip->base + chip->ngpio <= base)
+			break;
+		else
+			/* nope, check the space right before the chip */
+			base = chip->base - ngpio;
+	}
+
+	if (gpio_is_valid(base)) {
+		pr_debug("%s: found new base at %d\n", __func__, base);
+		return base;
+	} else {
+		pr_err("%s: cannot find free range\n", __func__);
+		return -ENOSPC;
+	}
+}
+
+/**
+ * gpiod_get_direction - return the current direction of a GPIO
+ * @desc:	GPIO to get the direction of
+ *
+ * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
+ *
+ * This function may sleep if gpiod_cansleep() is true.
+ */
+int gpiod_get_direction(struct gpio_desc *desc)
+{
+	struct gpio_chip	*chip;
+	unsigned		offset;
+	int			status = -EINVAL;
+
+	chip = gpiod_to_chip(desc);
+	offset = gpio_chip_hwgpio(desc);
+
+	if (!chip->get_direction)
+		return status;
+
+	status = chip->get_direction(chip, offset);
+	if (status > 0) {
+		/* GPIOF_DIR_IN, or other positive */
+		status = 1;
+		clear_bit(FLAG_IS_OUT, &desc->flags);
+	}
+	if (status == 0) {
+		/* GPIOF_DIR_OUT */
+		set_bit(FLAG_IS_OUT, &desc->flags);
+	}
+	return status;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_direction);
+
+/*
+ * Add a new chip to the global chips list, keeping the list of chips sorted
+ * by base order.
+ *
+ * Return -EBUSY if the new chip overlaps with some other chip's integer
+ * space.
+ */
+static int gpiochip_add_to_list(struct gpio_chip *chip)
+{
+	struct list_head *pos = &gpio_chips;
+	struct gpio_chip *_chip;
+	int err = 0;
+
+	/* find where to insert our chip */
+	list_for_each(pos, &gpio_chips) {
+		_chip = list_entry(pos, struct gpio_chip, list);
+		/* shall we insert before _chip? */
+		if (_chip->base >= chip->base + chip->ngpio)
+			break;
+	}
+
+	/* are we stepping on the chip right before? */
+	if (pos != &gpio_chips && pos->prev != &gpio_chips) {
+		_chip = list_entry(pos->prev, struct gpio_chip, list);
+		if (_chip->base + _chip->ngpio > chip->base) {
+			dev_err(chip->dev,
+			       "GPIO integer space overlap, cannot add chip\n");
+			err = -EBUSY;
+		}
+	}
+
+	if (!err)
+		list_add_tail(&chip->list, pos);
+
+	return err;
+}
+
+/**
+ * gpiochip_add() - register a gpio_chip
+ * @chip: the chip to register, with chip->base initialized
+ * Context: potentially before irqs will work
+ *
+ * Returns a negative errno if the chip can't be registered, such as
+ * because the chip->base is invalid or already associated with a
+ * different chip.  Otherwise it returns zero as a success code.
+ *
+ * When gpiochip_add() is called very early during boot, so that GPIOs
+ * can be freely used, the chip->dev device must be registered before
+ * the gpio framework's arch_initcall().  Otherwise sysfs initialization
+ * for GPIOs will fail rudely.
+ *
+ * If chip->base is negative, this requests dynamic assignment of
+ * a range of valid GPIOs.
+ */
+int gpiochip_add(struct gpio_chip *chip)
+{
+	unsigned long	flags;
+	int		status = 0;
+	unsigned	id;
+	int		base = chip->base;
+	struct gpio_desc *descs;
+
+	descs = kcalloc(chip->ngpio, sizeof(descs[0]), GFP_KERNEL);
+	if (!descs)
+		return -ENOMEM;
+
+	spin_lock_irqsave(&gpio_lock, flags);
+
+	if (base < 0) {
+		base = gpiochip_find_base(chip->ngpio);
+		if (base < 0) {
+			status = base;
+			spin_unlock_irqrestore(&gpio_lock, flags);
+			goto err_free_descs;
+		}
+		chip->base = base;
+	}
+
+	status = gpiochip_add_to_list(chip);
+	if (status) {
+		spin_unlock_irqrestore(&gpio_lock, flags);
+		goto err_free_descs;
+	}
+
+	for (id = 0; id < chip->ngpio; id++) {
+		struct gpio_desc *desc = &descs[id];
+
+		desc->chip = chip;
+
+		/* REVISIT: most hardware initializes GPIOs as inputs (often
+		 * with pullups enabled) so power usage is minimized. Linux
+		 * code should set the gpio direction first thing; but until
+		 * it does, and in case chip->get_direction is not set, we may
+		 * expose the wrong direction in sysfs.
+		 */
+		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
+	}
+
+	chip->desc = descs;
+
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+#ifdef CONFIG_PINCTRL
+	INIT_LIST_HEAD(&chip->pin_ranges);
+#endif
+
+	of_gpiochip_add(chip);
+	acpi_gpiochip_add(chip);
+
+	status = gpiochip_export(chip);
+	if (status)
+		goto err_remove_chip;
+
+	pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__,
+		chip->base, chip->base + chip->ngpio - 1,
+		chip->label ? : "generic");
+
+	return 0;
+
+err_remove_chip:
+	acpi_gpiochip_remove(chip);
+	gpiochip_free_hogs(chip);
+	of_gpiochip_remove(chip);
+	spin_lock_irqsave(&gpio_lock, flags);
+	list_del(&chip->list);
+	spin_unlock_irqrestore(&gpio_lock, flags);
+	chip->desc = NULL;
+err_free_descs:
+	kfree(descs);
+
+	/* failures here can mean systems won't boot... */
+	pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__,
+		chip->base, chip->base + chip->ngpio - 1,
+		chip->label ? : "generic");
+	return status;
+}
+EXPORT_SYMBOL_GPL(gpiochip_add);
+
+/**
+ * gpiochip_remove() - unregister a gpio_chip
+ * @chip: the chip to unregister
+ *
+ * A gpio_chip with any GPIOs still requested may not be removed.
+ */
+void gpiochip_remove(struct gpio_chip *chip)
+{
+	unsigned long	flags;
+	unsigned	id;
+
+	gpiochip_unexport(chip);
+
+	gpiochip_irqchip_remove(chip);
+
+	acpi_gpiochip_remove(chip);
+	gpiochip_remove_pin_ranges(chip);
+	gpiochip_free_hogs(chip);
+	of_gpiochip_remove(chip);
+
+	spin_lock_irqsave(&gpio_lock, flags);
+	for (id = 0; id < chip->ngpio; id++) {
+		if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags))
+			dev_crit(chip->dev, "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
+	}
+	for (id = 0; id < chip->ngpio; id++)
+		chip->desc[id].chip = NULL;
+
+	list_del(&chip->list);
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	kfree(chip->desc);
+	chip->desc = NULL;
+}
+EXPORT_SYMBOL_GPL(gpiochip_remove);
+
+/**
+ * gpiochip_find() - iterator for locating a specific gpio_chip
+ * @data: data to pass to match function
+ * @callback: Callback function to check gpio_chip
+ *
+ * Similar to bus_find_device.  It returns a reference to a gpio_chip as
+ * determined by a user supplied @match callback.  The callback should return
+ * 0 if the device doesn't match and non-zero if it does.  If the callback is
+ * non-zero, this function will return to the caller and not iterate over any
+ * more gpio_chips.
+ */
+struct gpio_chip *gpiochip_find(void *data,
+				int (*match)(struct gpio_chip *chip,
+					     void *data))
+{
+	struct gpio_chip *chip;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpio_lock, flags);
+	list_for_each_entry(chip, &gpio_chips, list)
+		if (match(chip, data))
+			break;
+
+	/* No match? */
+	if (&chip->list == &gpio_chips)
+		chip = NULL;
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	return chip;
+}
+EXPORT_SYMBOL_GPL(gpiochip_find);
+
+static int gpiochip_match_name(struct gpio_chip *chip, void *data)
+{
+	const char *name = data;
+
+	return !strcmp(chip->label, name);
+}
+
+static struct gpio_chip *find_chip_by_name(const char *name)
+{
+	return gpiochip_find((void *)name, gpiochip_match_name);
+}
+
+#ifdef CONFIG_GPIOLIB_IRQCHIP
+
+/*
+ * The following is irqchip helper code for gpiochips.
+ */
+
+/**
+ * gpiochip_set_chained_irqchip() - sets a chained irqchip to a gpiochip
+ * @gpiochip: the gpiochip to set the irqchip chain to
+ * @irqchip: the irqchip to chain to the gpiochip
+ * @parent_irq: the irq number corresponding to the parent IRQ for this
+ * chained irqchip
+ * @parent_handler: the parent interrupt handler for the accumulated IRQ
+ * coming out of the gpiochip. If the interrupt is nested rather than
+ * cascaded, pass NULL in this handler argument
+ */
+void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
+				  struct irq_chip *irqchip,
+				  int parent_irq,
+				  irq_flow_handler_t parent_handler)
+{
+	unsigned int offset;
+
+	if (!gpiochip->irqdomain) {
+		chip_err(gpiochip, "called %s before setting up irqchip\n",
+			 __func__);
+		return;
+	}
+
+	if (parent_handler) {
+		if (gpiochip->can_sleep) {
+			chip_err(gpiochip,
+				 "you cannot have chained interrupts on a "
+				 "chip that may sleep\n");
+			return;
+		}
+		/*
+		 * The parent irqchip is already using the chip_data for this
+		 * irqchip, so our callbacks simply use the handler_data.
+		 */
+		irq_set_handler_data(parent_irq, gpiochip);
+		irq_set_chained_handler(parent_irq, parent_handler);
+	}
+
+	/* Set the parent IRQ for all affected IRQs */
+	for (offset = 0; offset < gpiochip->ngpio; offset++)
+		irq_set_parent(irq_find_mapping(gpiochip->irqdomain, offset),
+			       parent_irq);
+}
+EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);
+
+/*
+ * This lock class tells lockdep that GPIO irqs are in a different
+ * category than their parents, so it won't report false recursion.
+ */
+static struct lock_class_key gpiochip_irq_lock_class;
+
+/**
+ * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip
+ * @d: the irqdomain used by this irqchip
+ * @irq: the global irq number used by this GPIO irqchip irq
+ * @hwirq: the local IRQ/GPIO line offset on this gpiochip
+ *
+ * This function will set up the mapping for a certain IRQ line on a
+ * gpiochip by assigning the gpiochip as chip data, and using the irqchip
+ * stored inside the gpiochip.
+ */
+static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
+			    irq_hw_number_t hwirq)
+{
+	struct gpio_chip *chip = d->host_data;
+
+	irq_set_chip_data(irq, chip);
+	irq_set_lockdep_class(irq, &gpiochip_irq_lock_class);
+	irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
+	/* Chips that can sleep need nested thread handlers */
+	if (chip->can_sleep && !chip->irq_not_threaded)
+		irq_set_nested_thread(irq, 1);
+#ifdef CONFIG_ARM
+	set_irq_flags(irq, IRQF_VALID);
+#else
+	irq_set_noprobe(irq);
+#endif
+	/*
+	 * No set-up of the hardware will happen if IRQ_TYPE_NONE
+	 * is passed as default type.
+	 */
+	if (chip->irq_default_type != IRQ_TYPE_NONE)
+		irq_set_irq_type(irq, chip->irq_default_type);
+
+	return 0;
+}
+
+static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
+{
+	struct gpio_chip *chip = d->host_data;
+
+#ifdef CONFIG_ARM
+	set_irq_flags(irq, 0);
+#endif
+	if (chip->can_sleep)
+		irq_set_nested_thread(irq, 0);
+	irq_set_chip_and_handler(irq, NULL, NULL);
+	irq_set_chip_data(irq, NULL);
+}
+
+static const struct irq_domain_ops gpiochip_domain_ops = {
+	.map	= gpiochip_irq_map,
+	.unmap	= gpiochip_irq_unmap,
+	/* Virtually all GPIO irqchips are twocell:ed */
+	.xlate	= irq_domain_xlate_twocell,
+};
+
+static int gpiochip_irq_reqres(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+
+	if (gpiochip_lock_as_irq(chip, d->hwirq)) {
+		chip_err(chip,
+			"unable to lock HW IRQ %lu for IRQ\n",
+			d->hwirq);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static void gpiochip_irq_relres(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+
+	gpiochip_unlock_as_irq(chip, d->hwirq);
+}
+
+static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	return irq_find_mapping(chip->irqdomain, offset);
+}
+
+/**
+ * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip
+ * @gpiochip: the gpiochip to remove the irqchip from
+ *
+ * This is called only from gpiochip_remove()
+ */
+static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
+{
+	unsigned int offset;
+
+	acpi_gpiochip_free_interrupts(gpiochip);
+
+	/* Remove all IRQ mappings and delete the domain */
+	if (gpiochip->irqdomain) {
+		for (offset = 0; offset < gpiochip->ngpio; offset++)
+			irq_dispose_mapping(
+				irq_find_mapping(gpiochip->irqdomain, offset));
+		irq_domain_remove(gpiochip->irqdomain);
+	}
+
+	if (gpiochip->irqchip) {
+		gpiochip->irqchip->irq_request_resources = NULL;
+		gpiochip->irqchip->irq_release_resources = NULL;
+		gpiochip->irqchip = NULL;
+	}
+}
+
+/**
+ * gpiochip_irqchip_add() - adds an irqchip to a gpiochip
+ * @gpiochip: the gpiochip to add the irqchip to
+ * @irqchip: the irqchip to add to the gpiochip
+ * @first_irq: if not dynamically assigned, the base (first) IRQ to
+ * allocate gpiochip irqs from
+ * @handler: the irq handler to use (often a predefined irq core function)
+ * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE
+ * to have the core avoid setting up any default type in the hardware.
+ *
+ * This function closely associates a certain irqchip with a certain
+ * gpiochip, providing an irq domain to translate the local IRQs to
+ * global irqs in the gpiolib core, and making sure that the gpiochip
+ * is passed as chip data to all related functions. Driver callbacks
+ * need to use container_of() to get their local state containers back
+ * from the gpiochip passed as chip data. An irqdomain will be stored
+ * in the gpiochip that shall be used by the driver to handle IRQ number
+ * translation. The gpiochip will need to be initialized and registered
+ * before calling this function.
+ *
+ * This function will handle two cell:ed simple IRQs and assumes all
+ * the pins on the gpiochip can generate a unique IRQ. Everything else
+ * need to be open coded.
+ */
+int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
+			 struct irq_chip *irqchip,
+			 unsigned int first_irq,
+			 irq_flow_handler_t handler,
+			 unsigned int type)
+{
+	struct device_node *of_node;
+	unsigned int offset;
+	unsigned irq_base = 0;
+
+	if (!gpiochip || !irqchip)
+		return -EINVAL;
+
+	if (!gpiochip->dev) {
+		pr_err("missing gpiochip .dev parent pointer\n");
+		return -EINVAL;
+	}
+	of_node = gpiochip->dev->of_node;
+#ifdef CONFIG_OF_GPIO
+	/*
+	 * If the gpiochip has an assigned OF node this takes precendence
+	 * FIXME: get rid of this and use gpiochip->dev->of_node everywhere
+	 */
+	if (gpiochip->of_node)
+		of_node = gpiochip->of_node;
+#endif
+	gpiochip->irqchip = irqchip;
+	gpiochip->irq_handler = handler;
+	gpiochip->irq_default_type = type;
+	gpiochip->to_irq = gpiochip_to_irq;
+	gpiochip->irqdomain = irq_domain_add_simple(of_node,
+					gpiochip->ngpio, first_irq,
+					&gpiochip_domain_ops, gpiochip);
+	if (!gpiochip->irqdomain) {
+		gpiochip->irqchip = NULL;
+		return -EINVAL;
+	}
+	irqchip->irq_request_resources = gpiochip_irq_reqres;
+	irqchip->irq_release_resources = gpiochip_irq_relres;
+
+	/*
+	 * Prepare the mapping since the irqchip shall be orthogonal to
+	 * any gpiochip calls. If the first_irq was zero, this is
+	 * necessary to allocate descriptors for all IRQs.
+	 */
+	for (offset = 0; offset < gpiochip->ngpio; offset++) {
+		irq_base = irq_create_mapping(gpiochip->irqdomain, offset);
+		if (offset == 0)
+			/*
+			 * Store the base into the gpiochip to be used when
+			 * unmapping the irqs.
+			 */
+			gpiochip->irq_base = irq_base;
+	}
+
+	acpi_gpiochip_request_interrupts(gpiochip);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gpiochip_irqchip_add);
+
+#else /* CONFIG_GPIOLIB_IRQCHIP */
+
+static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}
+
+#endif /* CONFIG_GPIOLIB_IRQCHIP */
+
+#ifdef CONFIG_PINCTRL
+
+/**
+ * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
+ * @chip: the gpiochip to add the range for
+ * @pinctrl: the dev_name() of the pin controller to map to
+ * @gpio_offset: the start offset in the current gpio_chip number space
+ * @pin_group: name of the pin group inside the pin controller
+ */
+int gpiochip_add_pingroup_range(struct gpio_chip *chip,
+			struct pinctrl_dev *pctldev,
+			unsigned int gpio_offset, const char *pin_group)
+{
+	struct gpio_pin_range *pin_range;
+	int ret;
+
+	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
+	if (!pin_range) {
+		chip_err(chip, "failed to allocate pin ranges\n");
+		return -ENOMEM;
+	}
+
+	/* Use local offset as range ID */
+	pin_range->range.id = gpio_offset;
+	pin_range->range.gc = chip;
+	pin_range->range.name = chip->label;
+	pin_range->range.base = chip->base + gpio_offset;
+	pin_range->pctldev = pctldev;
+
+	ret = pinctrl_get_group_pins(pctldev, pin_group,
+					&pin_range->range.pins,
+					&pin_range->range.npins);
+	if (ret < 0) {
+		kfree(pin_range);
+		return ret;
+	}
+
+	pinctrl_add_gpio_range(pctldev, &pin_range->range);
+
+	chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n",
+		 gpio_offset, gpio_offset + pin_range->range.npins - 1,
+		 pinctrl_dev_get_devname(pctldev), pin_group);
+
+	list_add_tail(&pin_range->node, &chip->pin_ranges);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
+
+/**
+ * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
+ * @chip: the gpiochip to add the range for
+ * @pinctrl_name: the dev_name() of the pin controller to map to
+ * @gpio_offset: the start offset in the current gpio_chip number space
+ * @pin_offset: the start offset in the pin controller number space
+ * @npins: the number of pins from the offset of each pin space (GPIO and
+ *	pin controller) to accumulate in this range
+ */
+int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
+			   unsigned int gpio_offset, unsigned int pin_offset,
+			   unsigned int npins)
+{
+	struct gpio_pin_range *pin_range;
+	int ret;
+
+	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
+	if (!pin_range) {
+		chip_err(chip, "failed to allocate pin ranges\n");
+		return -ENOMEM;
+	}
+
+	/* Use local offset as range ID */
+	pin_range->range.id = gpio_offset;
+	pin_range->range.gc = chip;
+	pin_range->range.name = chip->label;
+	pin_range->range.base = chip->base + gpio_offset;
+	pin_range->range.pin_base = pin_offset;
+	pin_range->range.npins = npins;
+	pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
+			&pin_range->range);
+	if (IS_ERR(pin_range->pctldev)) {
+		ret = PTR_ERR(pin_range->pctldev);
+		chip_err(chip, "could not create pin range\n");
+		kfree(pin_range);
+		return ret;
+	}
+	chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
+		 gpio_offset, gpio_offset + npins - 1,
+		 pinctl_name,
+		 pin_offset, pin_offset + npins - 1);
+
+	list_add_tail(&pin_range->node, &chip->pin_ranges);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
+
+/**
+ * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
+ * @chip: the chip to remove all the mappings for
+ */
+void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
+{
+	struct gpio_pin_range *pin_range, *tmp;
+
+	list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
+		list_del(&pin_range->node);
+		pinctrl_remove_gpio_range(pin_range->pctldev,
+				&pin_range->range);
+		kfree(pin_range);
+	}
+}
+EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
+
+#endif /* CONFIG_PINCTRL */
+
+/* These "optional" allocation calls help prevent drivers from stomping
+ * on each other, and help provide better diagnostics in debugfs.
+ * They're called even less than the "set direction" calls.
+ */
+static int __gpiod_request(struct gpio_desc *desc, const char *label)
+{
+	struct gpio_chip	*chip = desc->chip;
+	int			status;
+	unsigned long		flags;
+
+	spin_lock_irqsave(&gpio_lock, flags);
+
+	/* NOTE:  gpio_request() can be called in early boot,
+	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
+	 */
+
+	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
+		desc_set_label(desc, label ? : "?");
+		status = 0;
+	} else {
+		status = -EBUSY;
+		goto done;
+	}
+
+	if (chip->request) {
+		/* chip->request may sleep */
+		spin_unlock_irqrestore(&gpio_lock, flags);
+		status = chip->request(chip, gpio_chip_hwgpio(desc));
+		spin_lock_irqsave(&gpio_lock, flags);
+
+		if (status < 0) {
+			desc_set_label(desc, NULL);
+			clear_bit(FLAG_REQUESTED, &desc->flags);
+			goto done;
+		}
+	}
+	if (chip->get_direction) {
+		/* chip->get_direction may sleep */
+		spin_unlock_irqrestore(&gpio_lock, flags);
+		gpiod_get_direction(desc);
+		spin_lock_irqsave(&gpio_lock, flags);
+	}
+done:
+	spin_unlock_irqrestore(&gpio_lock, flags);
+	return status;
+}
+
+int gpiod_request(struct gpio_desc *desc, const char *label)
+{
+	int status = -EPROBE_DEFER;
+	struct gpio_chip *chip;
+
+	if (!desc) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+
+	chip = desc->chip;
+	if (!chip)
+		goto done;
+
+	if (try_module_get(chip->owner)) {
+		status = __gpiod_request(desc, label);
+		if (status < 0)
+			module_put(chip->owner);
+	}
+
+done:
+	if (status)
+		gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+
+	return status;
+}
+
+static bool __gpiod_free(struct gpio_desc *desc)
+{
+	bool			ret = false;
+	unsigned long		flags;
+	struct gpio_chip	*chip;
+
+	might_sleep();
+
+	gpiod_unexport(desc);
+
+	spin_lock_irqsave(&gpio_lock, flags);
+
+	chip = desc->chip;
+	if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
+		if (chip->free) {
+			spin_unlock_irqrestore(&gpio_lock, flags);
+			might_sleep_if(chip->can_sleep);
+			chip->free(chip, gpio_chip_hwgpio(desc));
+			spin_lock_irqsave(&gpio_lock, flags);
+		}
+		desc_set_label(desc, NULL);
+		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
+		clear_bit(FLAG_REQUESTED, &desc->flags);
+		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
+		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
+		clear_bit(FLAG_IS_HOGGED, &desc->flags);
+		ret = true;
+	}
+
+	spin_unlock_irqrestore(&gpio_lock, flags);
+	return ret;
+}
+
+void gpiod_free(struct gpio_desc *desc)
+{
+	if (desc && __gpiod_free(desc))
+		module_put(desc->chip->owner);
+	else
+		WARN_ON(extra_checks);
+}
+
+/**
+ * gpiochip_is_requested - return string iff signal was requested
+ * @chip: controller managing the signal
+ * @offset: of signal within controller's 0..(ngpio - 1) range
+ *
+ * Returns NULL if the GPIO is not currently requested, else a string.
+ * The string returned is the label passed to gpio_request(); if none has been
+ * passed it is a meaningless, non-NULL constant.
+ *
+ * This function is for use by GPIO controller drivers.  The label can
+ * help with diagnostics, and knowing that the signal is used as a GPIO
+ * can help avoid accidentally multiplexing it to another controller.
+ */
+const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
+{
+	struct gpio_desc *desc;
+
+	if (!GPIO_OFFSET_VALID(chip, offset))
+		return NULL;
+
+	desc = &chip->desc[offset];
+
+	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
+		return NULL;
+	return desc->label;
+}
+EXPORT_SYMBOL_GPL(gpiochip_is_requested);
+
+/**
+ * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
+ * @desc: GPIO descriptor to request
+ * @label: label for the GPIO
+ *
+ * Function allows GPIO chip drivers to request and use their own GPIO
+ * descriptors via gpiolib API. Difference to gpiod_request() is that this
+ * function will not increase reference count of the GPIO chip module. This
+ * allows the GPIO chip module to be unloaded as needed (we assume that the
+ * GPIO chip driver handles freeing the GPIOs it has requested).
+ */
+struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
+					    const char *label)
+{
+	struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum);
+	int err;
+
+	if (IS_ERR(desc)) {
+		chip_err(chip, "failed to get GPIO descriptor\n");
+		return desc;
+	}
+
+	err = __gpiod_request(desc, label);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(gpiochip_request_own_desc);
+
+/**
+ * gpiochip_free_own_desc - Free GPIO requested by the chip driver
+ * @desc: GPIO descriptor to free
+ *
+ * Function frees the given GPIO requested previously with
+ * gpiochip_request_own_desc().
+ */
+void gpiochip_free_own_desc(struct gpio_desc *desc)
+{
+	if (desc)
+		__gpiod_free(desc);
+}
+EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
+
+/* Drivers MUST set GPIO direction before making get/set calls.  In
+ * some cases this is done in early boot, before IRQs are enabled.
+ *
+ * As a rule these aren't called more than once (except for drivers
+ * using the open-drain emulation idiom) so these are natural places
+ * to accumulate extra debugging checks.  Note that we can't (yet)
+ * rely on gpio_request() having been called beforehand.
+ */
+
+/**
+ * gpiod_direction_input - set the GPIO direction to input
+ * @desc:	GPIO to set to input
+ *
+ * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
+ * be called safely on it.
+ *
+ * Return 0 in case of success, else an error code.
+ */
+int gpiod_direction_input(struct gpio_desc *desc)
+{
+	struct gpio_chip	*chip;
+	int			status = -EINVAL;
+
+	if (!desc || !desc->chip) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+
+	chip = desc->chip;
+	if (!chip->get || !chip->direction_input) {
+		gpiod_warn(desc,
+			"%s: missing get() or direction_input() operations\n",
+			__func__);
+		return -EIO;
+	}
+
+	status = chip->direction_input(chip, gpio_chip_hwgpio(desc));
+	if (status == 0)
+		clear_bit(FLAG_IS_OUT, &desc->flags);
+
+	trace_gpio_direction(desc_to_gpio(desc), 1, status);
+
+	return status;
+}
+EXPORT_SYMBOL_GPL(gpiod_direction_input);
+
+static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
+{
+	struct gpio_chip	*chip;
+	int			status = -EINVAL;
+
+	/* GPIOs used for IRQs shall not be set as output */
+	if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
+		gpiod_err(desc,
+			  "%s: tried to set a GPIO tied to an IRQ as output\n",
+			  __func__);
+		return -EIO;
+	}
+
+	/* Open drain pin should not be driven to 1 */
+	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
+		return gpiod_direction_input(desc);
+
+	/* Open source pin should not be driven to 0 */
+	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))
+		return gpiod_direction_input(desc);
+
+	chip = desc->chip;
+	if (!chip->set || !chip->direction_output) {
+		gpiod_warn(desc,
+		       "%s: missing set() or direction_output() operations\n",
+		       __func__);
+		return -EIO;
+	}
+
+	status = chip->direction_output(chip, gpio_chip_hwgpio(desc), value);
+	if (status == 0)
+		set_bit(FLAG_IS_OUT, &desc->flags);
+	trace_gpio_value(desc_to_gpio(desc), 0, value);
+	trace_gpio_direction(desc_to_gpio(desc), 0, status);
+	return status;
+}
+
+/**
+ * gpiod_direction_output_raw - set the GPIO direction to output
+ * @desc:	GPIO to set to output
+ * @value:	initial output value of the GPIO
+ *
+ * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
+ * be called safely on it. The initial value of the output must be specified
+ * as raw value on the physical line without regard for the ACTIVE_LOW status.
+ *
+ * Return 0 in case of success, else an error code.
+ */
+int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
+{
+	if (!desc || !desc->chip) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+	return _gpiod_direction_output_raw(desc, value);
+}
+EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
+
+/**
+ * gpiod_direction_output - set the GPIO direction to output
+ * @desc:	GPIO to set to output
+ * @value:	initial output value of the GPIO
+ *
+ * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
+ * be called safely on it. The initial value of the output must be specified
+ * as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
+ * account.
+ *
+ * Return 0 in case of success, else an error code.
+ */
+int gpiod_direction_output(struct gpio_desc *desc, int value)
+{
+	if (!desc || !desc->chip) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+		value = !value;
+	return _gpiod_direction_output_raw(desc, value);
+}
+EXPORT_SYMBOL_GPL(gpiod_direction_output);
+
+/**
+ * gpiod_set_debounce - sets @debounce time for a @gpio
+ * @gpio: the gpio to set debounce time
+ * @debounce: debounce time is microseconds
+ *
+ * returns -ENOTSUPP if the controller does not support setting
+ * debounce.
+ */
+int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
+{
+	struct gpio_chip	*chip;
+
+	if (!desc || !desc->chip) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+
+	chip = desc->chip;
+	if (!chip->set || !chip->set_debounce) {
+		gpiod_dbg(desc,
+			  "%s: missing set() or set_debounce() operations\n",
+			  __func__);
+		return -ENOTSUPP;
+	}
+
+	return chip->set_debounce(chip, gpio_chip_hwgpio(desc), debounce);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_debounce);
+
+/**
+ * gpiod_is_active_low - test whether a GPIO is active-low or not
+ * @desc: the gpio descriptor to test
+ *
+ * Returns 1 if the GPIO is active-low, 0 otherwise.
+ */
+int gpiod_is_active_low(const struct gpio_desc *desc)
+{
+	return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
+}
+EXPORT_SYMBOL_GPL(gpiod_is_active_low);
+
+/* I/O calls are only valid after configuration completed; the relevant
+ * "is this a valid GPIO" error checks should already have been done.
+ *
+ * "Get" operations are often inlinable as reading a pin value register,
+ * and masking the relevant bit in that register.
+ *
+ * When "set" operations are inlinable, they involve writing that mask to
+ * one register to set a low value, or a different register to set it high.
+ * Otherwise locking is needed, so there may be little value to inlining.
+ *
+ *------------------------------------------------------------------------
+ *
+ * IMPORTANT!!!  The hot paths -- get/set value -- assume that callers
+ * have requested the GPIO.  That can include implicit requesting by
+ * a direction setting call.  Marking a gpio as requested locks its chip
+ * in memory, guaranteeing that these table lookups need no more locking
+ * and that gpiochip_remove() will fail.
+ *
+ * REVISIT when debugging, consider adding some instrumentation to ensure
+ * that the GPIO was actually requested.
+ */
+
+static bool _gpiod_get_raw_value(const struct gpio_desc *desc)
+{
+	struct gpio_chip	*chip;
+	bool value;
+	int offset;
+
+	chip = desc->chip;
+	offset = gpio_chip_hwgpio(desc);
+	value = chip->get ? chip->get(chip, offset) : false;
+	trace_gpio_value(desc_to_gpio(desc), 1, value);
+	return value;
+}
+
+/**
+ * gpiod_get_raw_value() - return a gpio's raw value
+ * @desc: gpio whose value will be returned
+ *
+ * Return the GPIO's raw value, i.e. the value of the physical line disregarding
+ * its ACTIVE_LOW status.
+ *
+ * This function should be called from contexts where we cannot sleep, and will
+ * complain if the GPIO chip functions potentially sleep.
+ */
+int gpiod_get_raw_value(const struct gpio_desc *desc)
+{
+	if (!desc)
+		return 0;
+	/* Should be using gpio_get_value_cansleep() */
+	WARN_ON(desc->chip->can_sleep);
+	return _gpiod_get_raw_value(desc);
+}
+EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
+
+/**
+ * gpiod_get_value() - return a gpio's value
+ * @desc: gpio whose value will be returned
+ *
+ * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
+ * account.
+ *
+ * This function should be called from contexts where we cannot sleep, and will
+ * complain if the GPIO chip functions potentially sleep.
+ */
+int gpiod_get_value(const struct gpio_desc *desc)
+{
+	int value;
+	if (!desc)
+		return 0;
+	/* Should be using gpio_get_value_cansleep() */
+	WARN_ON(desc->chip->can_sleep);
+
+	value = _gpiod_get_raw_value(desc);
+	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+		value = !value;
+
+	return value;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_value);
+
+/*
+ *  _gpio_set_open_drain_value() - Set the open drain gpio's value.
+ * @desc: gpio descriptor whose state need to be set.
+ * @value: Non-zero for setting it HIGH otherise it will set to LOW.
+ */
+static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value)
+{
+	int err = 0;
+	struct gpio_chip *chip = desc->chip;
+	int offset = gpio_chip_hwgpio(desc);
+
+	if (value) {
+		err = chip->direction_input(chip, offset);
+		if (!err)
+			clear_bit(FLAG_IS_OUT, &desc->flags);
+	} else {
+		err = chip->direction_output(chip, offset, 0);
+		if (!err)
+			set_bit(FLAG_IS_OUT, &desc->flags);
+	}
+	trace_gpio_direction(desc_to_gpio(desc), value, err);
+	if (err < 0)
+		gpiod_err(desc,
+			  "%s: Error in set_value for open drain err %d\n",
+			  __func__, err);
+}
+
+/*
+ *  _gpio_set_open_source_value() - Set the open source gpio's value.
+ * @desc: gpio descriptor whose state need to be set.
+ * @value: Non-zero for setting it HIGH otherise it will set to LOW.
+ */
+static void _gpio_set_open_source_value(struct gpio_desc *desc, bool value)
+{
+	int err = 0;
+	struct gpio_chip *chip = desc->chip;
+	int offset = gpio_chip_hwgpio(desc);
+
+	if (value) {
+		err = chip->direction_output(chip, offset, 1);
+		if (!err)
+			set_bit(FLAG_IS_OUT, &desc->flags);
+	} else {
+		err = chip->direction_input(chip, offset);
+		if (!err)
+			clear_bit(FLAG_IS_OUT, &desc->flags);
+	}
+	trace_gpio_direction(desc_to_gpio(desc), !value, err);
+	if (err < 0)
+		gpiod_err(desc,
+			  "%s: Error in set_value for open source err %d\n",
+			  __func__, err);
+}
+
+static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value)
+{
+	struct gpio_chip	*chip;
+
+	chip = desc->chip;
+	trace_gpio_value(desc_to_gpio(desc), 0, value);
+	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
+		_gpio_set_open_drain_value(desc, value);
+	else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
+		_gpio_set_open_source_value(desc, value);
+	else
+		chip->set(chip, gpio_chip_hwgpio(desc), value);
+}
+
+/*
+ * set multiple outputs on the same chip;
+ * use the chip's set_multiple function if available;
+ * otherwise set the outputs sequentially;
+ * @mask: bit mask array; one bit per output; BITS_PER_LONG bits per word
+ *        defines which outputs are to be changed
+ * @bits: bit value array; one bit per output; BITS_PER_LONG bits per word
+ *        defines the values the outputs specified by mask are to be set to
+ */
+static void gpio_chip_set_multiple(struct gpio_chip *chip,
+				   unsigned long *mask, unsigned long *bits)
+{
+	if (chip->set_multiple) {
+		chip->set_multiple(chip, mask, bits);
+	} else {
+		int i;
+		for (i = 0; i < chip->ngpio; i++) {
+			if (mask[BIT_WORD(i)] == 0) {
+				/* no more set bits in this mask word;
+				 * skip ahead to the next word */
+				i = (BIT_WORD(i) + 1) * BITS_PER_LONG - 1;
+				continue;
+			}
+			/* set outputs if the corresponding mask bit is set */
+			if (__test_and_clear_bit(i, mask)) {
+				chip->set(chip, i, test_bit(i, bits));
+			}
+		}
+	}
+}
+
+static void gpiod_set_array_priv(bool raw, bool can_sleep,
+				 unsigned int array_size,
+				 struct gpio_desc **desc_array,
+				 int *value_array)
+{
+	int i = 0;
+
+	while (i < array_size) {
+		struct gpio_chip *chip = desc_array[i]->chip;
+		unsigned long mask[BITS_TO_LONGS(chip->ngpio)];
+		unsigned long bits[BITS_TO_LONGS(chip->ngpio)];
+		int count = 0;
+
+		if (!can_sleep) {
+			WARN_ON(chip->can_sleep);
+		}
+		memset(mask, 0, sizeof(mask));
+		do {
+			struct gpio_desc *desc = desc_array[i];
+			int hwgpio = gpio_chip_hwgpio(desc);
+			int value = value_array[i];
+
+			if (!raw && test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+				value = !value;
+			trace_gpio_value(desc_to_gpio(desc), 0, value);
+			/*
+			 * collect all normal outputs belonging to the same chip
+			 * open drain and open source outputs are set individually
+			 */
+			if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
+				_gpio_set_open_drain_value(desc,value);
+			} else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) {
+				_gpio_set_open_source_value(desc, value);
+			} else {
+				__set_bit(hwgpio, mask);
+				if (value) {
+					__set_bit(hwgpio, bits);
+				} else {
+					__clear_bit(hwgpio, bits);
+				}
+				count++;
+			}
+			i++;
+		} while ((i < array_size) && (desc_array[i]->chip == chip));
+		/* push collected bits to outputs */
+		if (count != 0) {
+			gpio_chip_set_multiple(chip, mask, bits);
+		}
+	}
+}
+
+/**
+ * gpiod_set_raw_value() - assign a gpio's raw value
+ * @desc: gpio whose value will be assigned
+ * @value: value to assign
+ *
+ * Set the raw value of the GPIO, i.e. the value of its physical line without
+ * regard for its ACTIVE_LOW status.
+ *
+ * This function should be called from contexts where we cannot sleep, and will
+ * complain if the GPIO chip functions potentially sleep.
+ */
+void gpiod_set_raw_value(struct gpio_desc *desc, int value)
+{
+	if (!desc)
+		return;
+	/* Should be using gpio_set_value_cansleep() */
+	WARN_ON(desc->chip->can_sleep);
+	_gpiod_set_raw_value(desc, value);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
+
+/**
+ * gpiod_set_value() - assign a gpio's value
+ * @desc: gpio whose value will be assigned
+ * @value: value to assign
+ *
+ * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
+ * account
+ *
+ * This function should be called from contexts where we cannot sleep, and will
+ * complain if the GPIO chip functions potentially sleep.
+ */
+void gpiod_set_value(struct gpio_desc *desc, int value)
+{
+	if (!desc)
+		return;
+	/* Should be using gpio_set_value_cansleep() */
+	WARN_ON(desc->chip->can_sleep);
+	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+		value = !value;
+	_gpiod_set_raw_value(desc, value);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_value);
+
+/**
+ * gpiod_set_raw_array() - assign values to an array of GPIOs
+ * @array_size: number of elements in the descriptor / value arrays
+ * @desc_array: array of GPIO descriptors whose values will be assigned
+ * @value_array: array of values to assign
+ *
+ * Set the raw values of the GPIOs, i.e. the values of the physical lines
+ * without regard for their ACTIVE_LOW status.
+ *
+ * This function should be called from contexts where we cannot sleep, and will
+ * complain if the GPIO chip functions potentially sleep.
+ */
+void gpiod_set_raw_array(unsigned int array_size,
+			 struct gpio_desc **desc_array, int *value_array)
+{
+	if (!desc_array)
+		return;
+	gpiod_set_array_priv(true, false, array_size, desc_array, value_array);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_raw_array);
+
+/**
+ * gpiod_set_array() - assign values to an array of GPIOs
+ * @array_size: number of elements in the descriptor / value arrays
+ * @desc_array: array of GPIO descriptors whose values will be assigned
+ * @value_array: array of values to assign
+ *
+ * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
+ * into account.
+ *
+ * This function should be called from contexts where we cannot sleep, and will
+ * complain if the GPIO chip functions potentially sleep.
+ */
+void gpiod_set_array(unsigned int array_size,
+		     struct gpio_desc **desc_array, int *value_array)
+{
+	if (!desc_array)
+		return;
+	gpiod_set_array_priv(false, false, array_size, desc_array, value_array);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_array);
+
+/**
+ * gpiod_cansleep() - report whether gpio value access may sleep
+ * @desc: gpio to check
+ *
+ */
+int gpiod_cansleep(const struct gpio_desc *desc)
+{
+	if (!desc)
+		return 0;
+	return desc->chip->can_sleep;
+}
+EXPORT_SYMBOL_GPL(gpiod_cansleep);
+
+/**
+ * gpiod_to_irq() - return the IRQ corresponding to a GPIO
+ * @desc: gpio whose IRQ will be returned (already requested)
+ *
+ * Return the IRQ corresponding to the passed GPIO, or an error code in case of
+ * error.
+ */
+int gpiod_to_irq(const struct gpio_desc *desc)
+{
+	struct gpio_chip	*chip;
+	int			offset;
+
+	if (!desc)
+		return -EINVAL;
+	chip = desc->chip;
+	offset = gpio_chip_hwgpio(desc);
+	return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
+}
+EXPORT_SYMBOL_GPL(gpiod_to_irq);
+
+/**
+ * gpiochip_lock_as_irq() - lock a GPIO to be used as IRQ
+ * @chip: the chip the GPIO to lock belongs to
+ * @offset: the offset of the GPIO to lock as IRQ
+ *
+ * This is used directly by GPIO drivers that want to lock down
+ * a certain GPIO line to be used for IRQs.
+ */
+int gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
+{
+	if (offset >= chip->ngpio)
+		return -EINVAL;
+
+	if (test_bit(FLAG_IS_OUT, &chip->desc[offset].flags)) {
+		chip_err(chip,
+			  "%s: tried to flag a GPIO set as output for IRQ\n",
+			  __func__);
+		return -EIO;
+	}
+
+	set_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq);
+
+/**
+ * gpiochip_unlock_as_irq() - unlock a GPIO used as IRQ
+ * @chip: the chip the GPIO to lock belongs to
+ * @offset: the offset of the GPIO to lock as IRQ
+ *
+ * This is used directly by GPIO drivers that want to indicate
+ * that a certain GPIO is no longer used exclusively for IRQ.
+ */
+void gpiochip_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
+{
+	if (offset >= chip->ngpio)
+		return;
+
+	clear_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
+}
+EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);
+
+/**
+ * gpiod_get_raw_value_cansleep() - return a gpio's raw value
+ * @desc: gpio whose value will be returned
+ *
+ * Return the GPIO's raw value, i.e. the value of the physical line disregarding
+ * its ACTIVE_LOW status.
+ *
+ * This function is to be called from contexts that can sleep.
+ */
+int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
+{
+	might_sleep_if(extra_checks);
+	if (!desc)
+		return 0;
+	return _gpiod_get_raw_value(desc);
+}
+EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
+
+/**
+ * gpiod_get_value_cansleep() - return a gpio's value
+ * @desc: gpio whose value will be returned
+ *
+ * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
+ * account.
+ *
+ * This function is to be called from contexts that can sleep.
+ */
+int gpiod_get_value_cansleep(const struct gpio_desc *desc)
+{
+	int value;
+
+	might_sleep_if(extra_checks);
+	if (!desc)
+		return 0;
+
+	value = _gpiod_get_raw_value(desc);
+	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+		value = !value;
+
+	return value;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
+
+/**
+ * gpiod_set_raw_value_cansleep() - assign a gpio's raw value
+ * @desc: gpio whose value will be assigned
+ * @value: value to assign
+ *
+ * Set the raw value of the GPIO, i.e. the value of its physical line without
+ * regard for its ACTIVE_LOW status.
+ *
+ * This function is to be called from contexts that can sleep.
+ */
+void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
+{
+	might_sleep_if(extra_checks);
+	if (!desc)
+		return;
+	_gpiod_set_raw_value(desc, value);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
+
+/**
+ * gpiod_set_value_cansleep() - assign a gpio's value
+ * @desc: gpio whose value will be assigned
+ * @value: value to assign
+ *
+ * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
+ * account
+ *
+ * This function is to be called from contexts that can sleep.
+ */
+void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
+{
+	might_sleep_if(extra_checks);
+	if (!desc)
+		return;
+
+	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+		value = !value;
+	_gpiod_set_raw_value(desc, value);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
+
+/**
+ * gpiod_set_raw_array_cansleep() - assign values to an array of GPIOs
+ * @array_size: number of elements in the descriptor / value arrays
+ * @desc_array: array of GPIO descriptors whose values will be assigned
+ * @value_array: array of values to assign
+ *
+ * Set the raw values of the GPIOs, i.e. the values of the physical lines
+ * without regard for their ACTIVE_LOW status.
+ *
+ * This function is to be called from contexts that can sleep.
+ */
+void gpiod_set_raw_array_cansleep(unsigned int array_size,
+				  struct gpio_desc **desc_array,
+				  int *value_array)
+{
+	might_sleep_if(extra_checks);
+	if (!desc_array)
+		return;
+	gpiod_set_array_priv(true, true, array_size, desc_array, value_array);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_raw_array_cansleep);
+
+/**
+ * gpiod_set_array_cansleep() - assign values to an array of GPIOs
+ * @array_size: number of elements in the descriptor / value arrays
+ * @desc_array: array of GPIO descriptors whose values will be assigned
+ * @value_array: array of values to assign
+ *
+ * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
+ * into account.
+ *
+ * This function is to be called from contexts that can sleep.
+ */
+void gpiod_set_array_cansleep(unsigned int array_size,
+			      struct gpio_desc **desc_array,
+			      int *value_array)
+{
+	might_sleep_if(extra_checks);
+	if (!desc_array)
+		return;
+	gpiod_set_array_priv(false, true, array_size, desc_array, value_array);
+}
+EXPORT_SYMBOL_GPL(gpiod_set_array_cansleep);
+
+/**
+ * gpiod_add_lookup_table() - register GPIO device consumers
+ * @table: table of consumers to register
+ */
+void gpiod_add_lookup_table(struct gpiod_lookup_table *table)
+{
+	mutex_lock(&gpio_lookup_lock);
+
+	list_add_tail(&table->list, &gpio_lookup_list);
+
+	mutex_unlock(&gpio_lookup_lock);
+}
+
+static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
+				      unsigned int idx,
+				      enum gpio_lookup_flags *flags)
+{
+	char prop_name[32]; /* 32 is max size of property name */
+	enum of_gpio_flags of_flags;
+	struct gpio_desc *desc;
+	unsigned int i;
+
+	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 (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
+			break;
+	}
+
+	if (IS_ERR(desc))
+		return desc;
+
+	if (of_flags & OF_GPIO_ACTIVE_LOW)
+		*flags |= GPIO_ACTIVE_LOW;
+
+	return desc;
+}
+
+static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
+					unsigned int idx,
+					enum gpio_lookup_flags *flags)
+{
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+	struct acpi_gpio_info info;
+	struct gpio_desc *desc;
+	char propname[32];
+	int i;
+
+	/* Try first from _DSD */
+	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
+		if (con_id && strcmp(con_id, "gpios")) {
+			snprintf(propname, sizeof(propname), "%s-%s",
+				 con_id, gpio_suffixes[i]);
+		} else {
+			snprintf(propname, sizeof(propname), "%s",
+				 gpio_suffixes[i]);
+		}
+
+		desc = acpi_get_gpiod_by_index(adev, propname, idx, &info);
+		if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
+			break;
+	}
+
+	/* Then from plain _CRS GPIOs */
+	if (IS_ERR(desc)) {
+		desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
+		if (IS_ERR(desc))
+			return desc;
+	}
+
+	if (info.active_low)
+		*flags |= GPIO_ACTIVE_LOW;
+
+	return desc;
+}
+
+static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
+{
+	const char *dev_id = dev ? dev_name(dev) : NULL;
+	struct gpiod_lookup_table *table;
+
+	mutex_lock(&gpio_lookup_lock);
+
+	list_for_each_entry(table, &gpio_lookup_list, list) {
+		if (table->dev_id && dev_id) {
+			/*
+			 * Valid strings on both ends, must be identical to have
+			 * a match
+			 */
+			if (!strcmp(table->dev_id, dev_id))
+				goto found;
+		} else {
+			/*
+			 * One of the pointers is NULL, so both must be to have
+			 * a match
+			 */
+			if (dev_id == table->dev_id)
+				goto found;
+		}
+	}
+	table = NULL;
+
+found:
+	mutex_unlock(&gpio_lookup_lock);
+	return table;
+}
+
+static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
+				    unsigned int idx,
+				    enum gpio_lookup_flags *flags)
+{
+	struct gpio_desc *desc = ERR_PTR(-ENOENT);
+	struct gpiod_lookup_table *table;
+	struct gpiod_lookup *p;
+
+	table = gpiod_find_lookup_table(dev);
+	if (!table)
+		return desc;
+
+	for (p = &table->table[0]; p->chip_label; p++) {
+		struct gpio_chip *chip;
+
+		/* idx must always match exactly */
+		if (p->idx != idx)
+			continue;
+
+		/* If the lookup entry has a con_id, require exact match */
+		if (p->con_id && (!con_id || strcmp(p->con_id, con_id)))
+			continue;
+
+		chip = find_chip_by_name(p->chip_label);
+
+		if (!chip) {
+			dev_err(dev, "cannot find GPIO chip %s\n",
+				p->chip_label);
+			return ERR_PTR(-ENODEV);
+		}
+
+		if (chip->ngpio <= p->chip_hwnum) {
+			dev_err(dev,
+				"requested GPIO %d is out of range [0..%d] for chip %s\n",
+				idx, chip->ngpio, chip->label);
+			return ERR_PTR(-EINVAL);
+		}
+
+		desc = gpiochip_get_desc(chip, p->chip_hwnum);
+		*flags = p->flags;
+
+		return desc;
+	}
+
+	return desc;
+}
+
+static int dt_gpio_count(struct device *dev, const char *con_id)
+{
+	int ret;
+	char propname[32];
+	unsigned int i;
+
+	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;
+}
+
+static int platform_gpio_count(struct device *dev, const char *con_id)
+{
+	struct gpiod_lookup_table *table;
+	struct gpiod_lookup *p;
+	unsigned int count = 0;
+
+	table = gpiod_find_lookup_table(dev);
+	if (!table)
+		return -ENOENT;
+
+	for (p = &table->table[0]; p->chip_label; p++) {
+		if ((con_id && p->con_id && !strcmp(con_id, p->con_id)) ||
+		    (!con_id && !p->con_id))
+			count++;
+	}
+	if (!count)
+		return -ENOENT;
+
+	return count;
+}
+
+/**
+ * gpiod_count - return the number of GPIOs associated with a device / function
+ *		or -ENOENT if no GPIO has been assigned to the requested function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ */
+int gpiod_count(struct device *dev, const char *con_id)
+{
+	int count = -ENOENT;
+
+	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
+		count = dt_gpio_count(dev, con_id);
+	else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev))
+		count = acpi_gpio_count(dev, con_id);
+
+	if (count < 0)
+		count = platform_gpio_count(dev, con_id);
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(gpiod_count);
+
+/**
+ * gpiod_get - obtain a GPIO for a given GPIO function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * Return the GPIO descriptor corresponding to the function con_id of device
+ * dev, -ENOENT if no GPIO has been assigned to the requested function, or
+ * another IS_ERR() code if an error occured while trying to acquire the GPIO.
+ */
+struct gpio_desc *__must_check __gpiod_get(struct device *dev, const char *con_id,
+					 enum gpiod_flags flags)
+{
+	return gpiod_get_index(dev, con_id, 0, flags);
+}
+EXPORT_SYMBOL_GPL(__gpiod_get);
+
+/**
+ * gpiod_get_optional - obtain an optional GPIO for a given GPIO function
+ * @dev: GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id: function within the GPIO consumer
+ * @flags: optional GPIO initialization flags
+ *
+ * This is equivalent to gpiod_get(), except that when no GPIO was assigned to
+ * the requested function it will return NULL. This is convenient for drivers
+ * that need to handle optional GPIOs.
+ */
+struct gpio_desc *__must_check __gpiod_get_optional(struct device *dev,
+						  const char *con_id,
+						  enum gpiod_flags flags)
+{
+	return gpiod_get_index_optional(dev, con_id, 0, flags);
+}
+EXPORT_SYMBOL_GPL(__gpiod_get_optional);
+
+
+/**
+ * gpiod_configure_flags - helper function to configure a given GPIO
+ * @desc:	gpio whose value will be assigned
+ * @con_id:	function within the GPIO consumer
+ * @lflags:	gpio_lookup_flags - returned from of_find_gpio() or
+ *		of_get_gpio_hog()
+ * @dflags:	gpiod_flags - optional GPIO initialization flags
+ *
+ * Return 0 on success, -ENOENT if no GPIO has been assigned to the
+ * requested function and/or index, or another IS_ERR() code if an error
+ * occurred while trying to acquire the GPIO.
+ */
+static int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
+		unsigned long lflags, enum gpiod_flags dflags)
+{
+	int status;
+
+	if (lflags & GPIO_ACTIVE_LOW)
+		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+	if (lflags & GPIO_OPEN_DRAIN)
+		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
+	if (lflags & GPIO_OPEN_SOURCE)
+		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+
+	/* No particular flag request, return here... */
+	if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) {
+		pr_debug("no flags found for %s\n", con_id);
+		return 0;
+	}
+
+	/* Process flags */
+	if (dflags & GPIOD_FLAGS_BIT_DIR_OUT)
+		status = gpiod_direction_output(desc,
+					      dflags & GPIOD_FLAGS_BIT_DIR_VAL);
+	else
+		status = gpiod_direction_input(desc);
+
+	return status;
+}
+
+/**
+ * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ * @idx:	index of the GPIO to obtain in the consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * This variant of gpiod_get() allows to access GPIOs other than the first
+ * defined one for functions that define several GPIOs.
+ *
+ * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the
+ * requested function and/or index, or another IS_ERR() code if an error
+ * occured while trying to acquire the GPIO.
+ */
+struct gpio_desc *__must_check __gpiod_get_index(struct device *dev,
+					       const char *con_id,
+					       unsigned int idx,
+					       enum gpiod_flags flags)
+{
+	struct gpio_desc *desc = NULL;
+	int status;
+	enum gpio_lookup_flags lookupflags = 0;
+
+	dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
+
+	if (dev) {
+		/* Using device tree? */
+		if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
+			dev_dbg(dev, "using device tree for GPIO lookup\n");
+			desc = of_find_gpio(dev, con_id, idx, &lookupflags);
+		} else if (ACPI_COMPANION(dev)) {
+			dev_dbg(dev, "using ACPI for GPIO lookup\n");
+			desc = acpi_find_gpio(dev, con_id, idx, &lookupflags);
+		}
+	}
+
+	/*
+	 * Either we are not using DT or ACPI, or their lookup did not return
+	 * a result. In that case, use platform lookup as a fallback.
+	 */
+	if (!desc || desc == ERR_PTR(-ENOENT)) {
+		dev_dbg(dev, "using lookup tables for GPIO lookup\n");
+		desc = gpiod_find(dev, con_id, idx, &lookupflags);
+	}
+
+	if (IS_ERR(desc)) {
+		dev_dbg(dev, "lookup for GPIO %s failed\n", con_id);
+		return desc;
+	}
+
+	status = gpiod_request(desc, con_id);
+	if (status < 0)
+		return ERR_PTR(status);
+
+	status = gpiod_configure_flags(desc, con_id, lookupflags, flags);
+	if (status < 0) {
+		dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
+		gpiod_put(desc);
+		return ERR_PTR(status);
+	}
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(__gpiod_get_index);
+
+/**
+ * fwnode_get_named_gpiod - obtain a GPIO from firmware node
+ * @fwnode:	handle of the firmware node
+ * @propname:	name of the firmware property representing the GPIO
+ *
+ * This function can be used for drivers that get their configuration
+ * from firmware.
+ *
+ * Function properly finds the corresponding GPIO using whatever is the
+ * underlying firmware interface and then makes sure that the GPIO
+ * descriptor is requested before it is returned to the caller.
+ *
+ * In case of error an ERR_PTR() is returned.
+ */
+struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
+					 const char *propname)
+{
+	struct gpio_desc *desc = ERR_PTR(-ENODEV);
+	bool active_low = false;
+	int ret;
+
+	if (!fwnode)
+		return ERR_PTR(-EINVAL);
+
+	if (is_of_node(fwnode)) {
+		enum of_gpio_flags flags;
+
+		desc = of_get_named_gpiod_flags(of_node(fwnode), propname, 0,
+						&flags);
+		if (!IS_ERR(desc))
+			active_low = flags & OF_GPIO_ACTIVE_LOW;
+	} else if (is_acpi_node(fwnode)) {
+		struct acpi_gpio_info info;
+
+		desc = acpi_get_gpiod_by_index(acpi_node(fwnode), propname, 0,
+					       &info);
+		if (!IS_ERR(desc))
+			active_low = info.active_low;
+	}
+
+	if (IS_ERR(desc))
+		return desc;
+
+	ret = gpiod_request(desc, NULL);
+	if (ret)
+		return ERR_PTR(ret);
+
+	/* Only value flag can be set from both DT and ACPI is active_low */
+	if (active_low)
+		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_named_gpiod);
+
+/**
+ * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO
+ *                            function
+ * @dev: GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id: function within the GPIO consumer
+ * @index: index of the GPIO to obtain in the consumer
+ * @flags: optional GPIO initialization flags
+ *
+ * This is equivalent to gpiod_get_index(), except that when no GPIO with the
+ * specified index was assigned to the requested function it will return NULL.
+ * This is convenient for drivers that need to handle optional GPIOs.
+ */
+struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
+							const char *con_id,
+							unsigned int index,
+							enum gpiod_flags flags)
+{
+	struct gpio_desc *desc;
+
+	desc = gpiod_get_index(dev, con_id, index, flags);
+	if (IS_ERR(desc)) {
+		if (PTR_ERR(desc) == -ENOENT)
+			return NULL;
+	}
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(__gpiod_get_index_optional);
+
+/**
+ * gpiod_hog - Hog the specified GPIO desc given the provided flags
+ * @desc:	gpio whose value will be assigned
+ * @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
+ */
+int gpiod_hog(struct gpio_desc *desc, const char *name,
+	      unsigned long lflags, enum gpiod_flags dflags)
+{
+	struct gpio_chip *chip;
+	struct gpio_desc *local_desc;
+	int hwnum;
+	int status;
+
+	chip = gpiod_to_chip(desc);
+	hwnum = gpio_chip_hwgpio(desc);
+
+	local_desc = gpiochip_request_own_desc(chip, hwnum, name);
+	if (IS_ERR(local_desc)) {
+		pr_debug("requesting own GPIO %s failed\n", name);
+		return PTR_ERR(local_desc);
+	}
+
+	status = gpiod_configure_flags(desc, name, lflags, dflags);
+	if (status < 0) {
+		pr_debug("setup of GPIO %s failed\n", name);
+		gpiochip_free_own_desc(desc);
+		return status;
+	}
+
+	/* Mark GPIO as hogged so it can be identified and removed later */
+	set_bit(FLAG_IS_HOGGED, &desc->flags);
+
+	pr_info("GPIO line %d (%s) hogged as %s%s\n",
+		desc_to_gpio(desc), name,
+		(dflags&GPIOD_FLAGS_BIT_DIR_OUT) ? "output" : "input",
+		(dflags&GPIOD_FLAGS_BIT_DIR_OUT) ?
+		  (dflags&GPIOD_FLAGS_BIT_DIR_VAL) ? "/high" : "/low":"");
+
+	return 0;
+}
+
+/**
+ * gpiochip_free_hogs - Scan gpio-controller chip and release GPIO hog
+ * @chip:	gpio chip to act on
+ *
+ * This is only used by of_gpiochip_remove to free hogged gpios
+ */
+static void gpiochip_free_hogs(struct gpio_chip *chip)
+{
+	int id;
+
+	for (id = 0; id < chip->ngpio; id++) {
+		if (test_bit(FLAG_IS_HOGGED, &chip->desc[id].flags))
+			gpiochip_free_own_desc(&chip->desc[id]);
+	}
+}
+
+/**
+ * gpiod_get_array - obtain multiple GPIOs from a multi-index GPIO function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * This function acquires all the GPIOs defined under a given function.
+ *
+ * Return a struct gpio_descs containing an array of descriptors, -ENOENT if
+ * no GPIO has been assigned to the requested function, or another IS_ERR()
+ * code if an error occurred while trying to acquire the GPIOs.
+ */
+struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
+						const char *con_id,
+						enum gpiod_flags flags)
+{
+	struct gpio_desc *desc;
+	struct gpio_descs *descs;
+	int count;
+
+	count = gpiod_count(dev, con_id);
+	if (count < 0)
+		return ERR_PTR(count);
+
+	descs = kzalloc(sizeof(*descs) + sizeof(descs->desc[0]) * count,
+			GFP_KERNEL);
+	if (!descs)
+		return ERR_PTR(-ENOMEM);
+
+	for (descs->ndescs = 0; descs->ndescs < count; ) {
+		desc = gpiod_get_index(dev, con_id, descs->ndescs, flags);
+		if (IS_ERR(desc)) {
+			gpiod_put_array(descs);
+			return ERR_CAST(desc);
+		}
+		descs->desc[descs->ndescs] = desc;
+		descs->ndescs++;
+	}
+	return descs;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_array);
+
+/**
+ * gpiod_get_array_optional - obtain multiple GPIOs from a multi-index GPIO
+ *                            function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * This is equivalent to gpiod_get_array(), except that when no GPIO was
+ * assigned to the requested function it will return NULL.
+ */
+struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev,
+							const char *con_id,
+							enum gpiod_flags flags)
+{
+	struct gpio_descs *descs;
+
+	descs = gpiod_get_array(dev, con_id, flags);
+	if (IS_ERR(descs) && (PTR_ERR(descs) == -ENOENT))
+		return NULL;
+
+	return descs;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_array_optional);
+
+/**
+ * gpiod_put - dispose of a GPIO descriptor
+ * @desc:	GPIO descriptor to dispose of
+ *
+ * No descriptor can be used after gpiod_put() has been called on it.
+ */
+void gpiod_put(struct gpio_desc *desc)
+{
+	gpiod_free(desc);
+}
+EXPORT_SYMBOL_GPL(gpiod_put);
+
+/**
+ * gpiod_put_array - dispose of multiple GPIO descriptors
+ * @descs:	struct gpio_descs containing an array of descriptors
+ */
+void gpiod_put_array(struct gpio_descs *descs)
+{
+	unsigned int i;
+
+	for (i = 0; i < descs->ndescs; i++)
+		gpiod_put(descs->desc[i]);
+
+	kfree(descs);
+}
+EXPORT_SYMBOL_GPL(gpiod_put_array);
+
+#ifdef CONFIG_DEBUG_FS
+
+static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
+{
+	unsigned		i;
+	unsigned		gpio = chip->base;
+	struct gpio_desc	*gdesc = &chip->desc[0];
+	int			is_out;
+	int			is_irq;
+
+	for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
+		if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
+			continue;
+
+		gpiod_get_direction(gdesc);
+		is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
+		is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags);
+		seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s",
+			gpio, gdesc->label,
+			is_out ? "out" : "in ",
+			chip->get
+				? (chip->get(chip, i) ? "hi" : "lo")
+				: "?  ",
+			is_irq ? "IRQ" : "   ");
+		seq_printf(s, "\n");
+	}
+}
+
+static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
+{
+	unsigned long flags;
+	struct gpio_chip *chip = NULL;
+	loff_t index = *pos;
+
+	s->private = "";
+
+	spin_lock_irqsave(&gpio_lock, flags);
+	list_for_each_entry(chip, &gpio_chips, list)
+		if (index-- == 0) {
+			spin_unlock_irqrestore(&gpio_lock, flags);
+			return chip;
+		}
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	return NULL;
+}
+
+static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	unsigned long flags;
+	struct gpio_chip *chip = v;
+	void *ret = NULL;
+
+	spin_lock_irqsave(&gpio_lock, flags);
+	if (list_is_last(&chip->list, &gpio_chips))
+		ret = NULL;
+	else
+		ret = list_entry(chip->list.next, struct gpio_chip, list);
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	s->private = "\n";
+	++*pos;
+
+	return ret;
+}
+
+static void gpiolib_seq_stop(struct seq_file *s, void *v)
+{
+}
+
+static int gpiolib_seq_show(struct seq_file *s, void *v)
+{
+	struct gpio_chip *chip = v;
+	struct device *dev;
+
+	seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
+			chip->base, chip->base + chip->ngpio - 1);
+	dev = chip->dev;
+	if (dev)
+		seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
+			dev_name(dev));
+	if (chip->label)
+		seq_printf(s, ", %s", chip->label);
+	if (chip->can_sleep)
+		seq_printf(s, ", can sleep");
+	seq_printf(s, ":\n");
+
+	if (chip->dbg_show)
+		chip->dbg_show(s, chip);
+	else
+		gpiolib_dbg_show(s, chip);
+
+	return 0;
+}
+
+static const struct seq_operations gpiolib_seq_ops = {
+	.start = gpiolib_seq_start,
+	.next = gpiolib_seq_next,
+	.stop = gpiolib_seq_stop,
+	.show = gpiolib_seq_show,
+};
+
+static int gpiolib_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &gpiolib_seq_ops);
+}
+
+static const struct file_operations gpiolib_operations = {
+	.owner		= THIS_MODULE,
+	.open		= gpiolib_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static int __init gpiolib_debugfs_init(void)
+{
+	/* /sys/kernel/debug/gpio */
+	(void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
+				NULL, NULL, &gpiolib_operations);
+	return 0;
+}
+subsys_initcall(gpiolib_debugfs_init);
+
+#endif	/* DEBUG_FS */