xref: /linux/drivers/gpio/gpiolib-acpi-core.c (revision bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43)

// SPDX-License-Identifier: GPL-2.0
/*
 * ACPI helpers for GPIO API
 *
 * Copyright (C) 2012, Intel Corporation
 * Authors: Mathias Nyman <mathias.nyman@linux.intel.com>
 *          Mika Westerberg <mika.westerberg@linux.intel.com>
 */

#include <linux/acpi.h>
#include <linux/dmi.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/mutex.h>
#include <linux/pinctrl/pinctrl.h>

#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/machine.h>

#include "gpiolib.h"
#include "gpiolib-acpi.h"

/**
 * struct acpi_gpio_event - ACPI GPIO event handler data
 *
 * @node:	  list-entry of the events list of the struct acpi_gpio_chip
 * @handle:	  handle of ACPI method to execute when the IRQ triggers
 * @handler:	  handler function to pass to request_irq() when requesting the IRQ
 * @pin:	  GPIO pin number on the struct gpio_chip
 * @irq:	  Linux IRQ number for the event, for request_irq() / free_irq()
 * @irqflags:	  flags to pass to request_irq() when requesting the IRQ
 * @irq_is_wake:  If the ACPI flags indicate the IRQ is a wakeup source
 * @irq_requested:True if request_irq() has been done
 * @desc:	  struct gpio_desc for the GPIO pin for this event
 */
struct acpi_gpio_event {
	struct list_head node;
	acpi_handle handle;
	irq_handler_t handler;
	unsigned int pin;
	unsigned int irq;
	unsigned long irqflags;
	bool irq_is_wake;
	bool irq_requested;
	struct gpio_desc *desc;
};

struct acpi_gpio_connection {
	struct list_head node;
	unsigned int pin;
	struct gpio_desc *desc;
};

struct acpi_gpio_chip {
	/*
	 * ACPICA requires that the first field of the context parameter
	 * passed to acpi_install_address_space_handler() is large enough
	 * to hold struct acpi_connection_info.
	 */
	struct acpi_connection_info conn_info;
	struct list_head conns;
	struct mutex conn_lock;
	struct gpio_chip *chip;
	struct list_head events;
	struct list_head deferred_req_irqs_list_entry;
};

/**
 * struct acpi_gpio_info - ACPI GPIO specific information
 * @adev: reference to ACPI device which consumes GPIO resource
 * @flags: GPIO initialization flags
 * @gpioint: if %true this GPIO is of type GpioInt otherwise type is GpioIo
 * @wake_capable: wake capability as provided by ACPI
 * @pin_config: pin bias as provided by ACPI
 * @polarity: interrupt polarity as provided by ACPI
 * @triggering: triggering type as provided by ACPI
 * @debounce: debounce timeout as provided by ACPI
 * @quirks: Linux specific quirks as provided by struct acpi_gpio_mapping
 */
struct acpi_gpio_info {
	struct acpi_device *adev;
	enum gpiod_flags flags;
	bool gpioint;
	bool wake_capable;
	int pin_config;
	int polarity;
	int triggering;
	unsigned int debounce;
	unsigned int quirks;
};

static int acpi_gpiochip_find(struct gpio_chip *gc, const void *data)
{
	/* First check the actual GPIO device */
	if (device_match_acpi_handle(&gc->gpiodev->dev, data))
		return true;

	/*
	 * When the ACPI device is artificially split to the banks of GPIOs,
	 * where each of them is represented by a separate GPIO device,
	 * the firmware node of the physical device may not be shared among
	 * the banks as they may require different values for the same property,
	 * e.g., number of GPIOs in a certain bank. In such case the ACPI handle
	 * of a GPIO device is NULL and can not be used. Hence we have to check
	 * the parent device to be sure that there is no match before bailing
	 * out.
	 */
	if (gc->parent)
		return device_match_acpi_handle(gc->parent, data);

	return false;
}

/**
 * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
 * @path:	ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
 * @pin:	ACPI GPIO pin number (0-based, controller-relative)
 *
 * Returns:
 * GPIO descriptor to use with Linux generic GPIO API.
 * If the GPIO cannot be translated or there is an error an ERR_PTR is
 * returned.
 *
 * Specifically returns %-EPROBE_DEFER if the referenced GPIO
 * controller does not have GPIO chip registered at the moment. This is to
 * support probe deferral.
 */
static struct gpio_desc *acpi_get_gpiod(char *path, unsigned int pin)
{
	acpi_handle handle;
	acpi_status status;

	status = acpi_get_handle(NULL, path, &handle);
	if (ACPI_FAILURE(status))
		return ERR_PTR(-ENODEV);

	struct gpio_device *gdev __free(gpio_device_put) =
				gpio_device_find(handle, acpi_gpiochip_find);
	if (!gdev)
		return ERR_PTR(-EPROBE_DEFER);

	/*
	 * FIXME: keep track of the reference to the GPIO device somehow
	 * instead of putting it here.
	 */
	return gpio_device_get_desc(gdev, pin);
}

static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
{
	struct acpi_gpio_event *event = data;

	acpi_evaluate_object(event->handle, NULL, NULL, NULL);

	return IRQ_HANDLED;
}

static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
{
	struct acpi_gpio_event *event = data;

	acpi_execute_simple_method(event->handle, NULL, event->pin);

	return IRQ_HANDLED;
}

static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
{
	/* The address of this function is used as a key. */
}

bool acpi_gpio_get_irq_resource(struct acpi_resource *ares,
				struct acpi_resource_gpio **agpio)
{
	struct acpi_resource_gpio *gpio;

	if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
		return false;

	gpio = &ares->data.gpio;
	if (gpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT)
		return false;

	*agpio = gpio;
	return true;
}
EXPORT_SYMBOL_GPL(acpi_gpio_get_irq_resource);

/**
 * acpi_gpio_get_io_resource - Fetch details of an ACPI resource if it is a GPIO
 *			       I/O resource or return False if not.
 * @ares:	Pointer to the ACPI resource to fetch
 * @agpio:	Pointer to a &struct acpi_resource_gpio to store the output pointer
 *
 * Returns:
 * %true if GpioIo resource is found, %false otherwise.
 */
bool acpi_gpio_get_io_resource(struct acpi_resource *ares,
			       struct acpi_resource_gpio **agpio)
{
	struct acpi_resource_gpio *gpio;

	if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
		return false;

	gpio = &ares->data.gpio;
	if (gpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
		return false;

	*agpio = gpio;
	return true;
}
EXPORT_SYMBOL_GPL(acpi_gpio_get_io_resource);

static void acpi_gpiochip_request_irq(struct acpi_gpio_chip *acpi_gpio,
				      struct acpi_gpio_event *event)
{
	struct device *parent = acpi_gpio->chip->parent;
	int ret, value;

	ret = request_threaded_irq(event->irq, NULL, event->handler,
				   event->irqflags | IRQF_ONESHOT, "ACPI:Event", event);
	if (ret) {
		dev_err(parent, "Failed to setup interrupt handler for %d\n", event->irq);
		return;
	}

	if (event->irq_is_wake)
		enable_irq_wake(event->irq);

	event->irq_requested = true;

	/* Make sure we trigger the initial state of edge-triggered IRQs */
	if (acpi_gpio_need_run_edge_events_on_boot() &&
	    (event->irqflags & (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING))) {
		value = gpiod_get_raw_value_cansleep(event->desc);
		if (((event->irqflags & IRQF_TRIGGER_RISING) && value == 1) ||
		    ((event->irqflags & IRQF_TRIGGER_FALLING) && value == 0))
			event->handler(event->irq, event);
	}
}

static void acpi_gpiochip_request_irqs(struct acpi_gpio_chip *acpi_gpio)
{
	struct acpi_gpio_event *event;

	list_for_each_entry(event, &acpi_gpio->events, node)
		acpi_gpiochip_request_irq(acpi_gpio, event);
}

static enum gpiod_flags
acpi_gpio_to_gpiod_flags(const struct acpi_resource_gpio *agpio, int polarity)
{
	/* GpioInt() implies input configuration */
	if (agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT)
		return GPIOD_IN;

	switch (agpio->io_restriction) {
	case ACPI_IO_RESTRICT_INPUT:
		return GPIOD_IN;
	case ACPI_IO_RESTRICT_OUTPUT:
		/*
		 * ACPI GPIO resources don't contain an initial value for the
		 * GPIO. Therefore we deduce that value from the pull field
		 * and the polarity instead. If the pin is pulled up we assume
		 * default to be high, if it is pulled down we assume default
		 * to be low, otherwise we leave pin untouched. For active low
		 * polarity values will be switched. See also
		 * Documentation/firmware-guide/acpi/gpio-properties.rst.
		 */
		switch (agpio->pin_config) {
		case ACPI_PIN_CONFIG_PULLUP:
			return polarity == GPIO_ACTIVE_LOW ? GPIOD_OUT_LOW : GPIOD_OUT_HIGH;
		case ACPI_PIN_CONFIG_PULLDOWN:
			return polarity == GPIO_ACTIVE_LOW ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
		default:
			break;
		}
		break;
	default:
		break;
	}

	/*
	 * Assume that the BIOS has configured the direction and pull
	 * accordingly.
	 */
	return GPIOD_ASIS;
}

static void acpi_gpio_set_debounce_timeout(struct gpio_desc *desc,
					   unsigned int acpi_debounce)
{
	int ret;

	/* ACPI uses hundredths of milliseconds units */
	acpi_debounce *= 10;
	ret = gpio_set_debounce_timeout(desc, acpi_debounce);
	if (ret)
		gpiod_warn(desc, "Failed to set debounce-timeout %u: %d\n",
			   acpi_debounce, ret);
}

static struct gpio_desc *acpi_request_own_gpiod(struct gpio_chip *chip,
						struct acpi_resource_gpio *agpio,
						unsigned int index,
						const char *label)
{
	int polarity = GPIO_ACTIVE_HIGH;
	enum gpiod_flags flags = acpi_gpio_to_gpiod_flags(agpio, polarity);
	unsigned int pin = agpio->pin_table[index];
	struct gpio_desc *desc;

	desc = gpiochip_request_own_desc(chip, pin, label, polarity, flags);
	if (IS_ERR(desc))
		return desc;

	acpi_gpio_set_debounce_timeout(desc, agpio->debounce_timeout);

	return desc;
}

static bool acpi_gpio_irq_is_wake(struct device *parent,
				  const struct acpi_resource_gpio *agpio)
{
	unsigned int pin = agpio->pin_table[0];

	if (agpio->wake_capable != ACPI_WAKE_CAPABLE)
		return false;

	if (acpi_gpio_in_ignore_list(ACPI_GPIO_IGNORE_WAKE, dev_name(parent), pin)) {
		dev_info(parent, "Ignoring wakeup on pin %u\n", pin);
		return false;
	}

	return true;
}

/* Always returns AE_OK so that we keep looping over the resources */
static acpi_status acpi_gpiochip_alloc_event(struct acpi_resource *ares,
					     void *context)
{
	struct acpi_gpio_chip *acpi_gpio = context;
	struct gpio_chip *chip = acpi_gpio->chip;
	struct acpi_resource_gpio *agpio;
	acpi_handle handle, evt_handle;
	struct acpi_gpio_event *event;
	irq_handler_t handler = NULL;
	struct gpio_desc *desc;
	unsigned int pin;
	int ret, irq;

	if (!acpi_gpio_get_irq_resource(ares, &agpio))
		return AE_OK;

	handle = ACPI_HANDLE(chip->parent);
	pin = agpio->pin_table[0];

	if (pin <= 255) {
		char ev_name[8];
		sprintf(ev_name, "_%c%02X",
			agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
			pin);
		if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
			handler = acpi_gpio_irq_handler;
	}
	if (!handler) {
		if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
			handler = acpi_gpio_irq_handler_evt;
	}
	if (!handler)
		return AE_OK;

	if (acpi_gpio_in_ignore_list(ACPI_GPIO_IGNORE_INTERRUPT, dev_name(chip->parent), pin)) {
		dev_info(chip->parent, "Ignoring interrupt on pin %u\n", pin);
		return AE_OK;
	}

	desc = acpi_request_own_gpiod(chip, agpio, 0, "ACPI:Event");
	if (IS_ERR(desc)) {
		dev_err(chip->parent,
			"Failed to request GPIO for pin 0x%04X, err %pe\n",
			pin, desc);
		return AE_OK;
	}

	ret = gpiochip_lock_as_irq(chip, pin);
	if (ret) {
		dev_err(chip->parent,
			"Failed to lock GPIO pin 0x%04X as interrupt, err %d\n",
			pin, ret);
		goto fail_free_desc;
	}

	irq = gpiod_to_irq(desc);
	if (irq < 0) {
		dev_err(chip->parent,
			"Failed to translate GPIO pin 0x%04X to IRQ, err %d\n",
			pin, irq);
		goto fail_unlock_irq;
	}

	event = kzalloc_obj(*event);
	if (!event)
		goto fail_unlock_irq;

	event->irqflags = IRQF_ONESHOT;
	if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
		if (agpio->polarity == ACPI_ACTIVE_HIGH)
			event->irqflags |= IRQF_TRIGGER_HIGH;
		else
			event->irqflags |= IRQF_TRIGGER_LOW;
	} else {
		switch (agpio->polarity) {
		case ACPI_ACTIVE_HIGH:
			event->irqflags |= IRQF_TRIGGER_RISING;
			break;
		case ACPI_ACTIVE_LOW:
			event->irqflags |= IRQF_TRIGGER_FALLING;
			break;
		default:
			event->irqflags |= IRQF_TRIGGER_RISING |
					   IRQF_TRIGGER_FALLING;
			break;
		}
	}

	event->handle = evt_handle;
	event->handler = handler;
	event->irq = irq;
	event->irq_is_wake = acpi_gpio_irq_is_wake(chip->parent, agpio);
	event->pin = pin;
	event->desc = desc;

	list_add_tail(&event->node, &acpi_gpio->events);

	return AE_OK;

fail_unlock_irq:
	gpiochip_unlock_as_irq(chip, pin);
fail_free_desc:
	gpiochip_free_own_desc(desc);

	return AE_OK;
}

/**
 * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
 * @chip:      GPIO chip
 *
 * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
 * handled by ACPI event methods which need to be called from the GPIO
 * chip's interrupt handler. acpi_gpiochip_request_interrupts() finds out which
 * GPIO pins have ACPI event methods and assigns interrupt handlers that calls
 * the ACPI event methods for those pins.
 */
void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
{
	struct acpi_gpio_chip *acpi_gpio;
	acpi_handle handle;
	acpi_status status;

	if (!chip->parent || !chip->to_irq)
		return;

	handle = ACPI_HANDLE(chip->parent);
	if (!handle)
		return;

	status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
	if (ACPI_FAILURE(status))
		return;

	if (acpi_quirk_skip_gpio_event_handlers())
		return;

	acpi_walk_resources(handle, METHOD_NAME__AEI,
			    acpi_gpiochip_alloc_event, acpi_gpio);

	if (acpi_gpio_add_to_deferred_list(&acpi_gpio->deferred_req_irqs_list_entry))
		return;

	acpi_gpiochip_request_irqs(acpi_gpio);
}
EXPORT_SYMBOL_GPL(acpi_gpiochip_request_interrupts);

/**
 * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts.
 * @chip:      GPIO chip
 *
 * Free interrupts associated with GPIO ACPI event method for the given
 * GPIO chip.
 */
void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
{
	struct acpi_gpio_chip *acpi_gpio;
	struct acpi_gpio_event *event, *ep;
	acpi_handle handle;
	acpi_status status;

	if (!chip->parent || !chip->to_irq)
		return;

	handle = ACPI_HANDLE(chip->parent);
	if (!handle)
		return;

	status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
	if (ACPI_FAILURE(status))
		return;

	acpi_gpio_remove_from_deferred_list(&acpi_gpio->deferred_req_irqs_list_entry);

	list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
		if (event->irq_requested) {
			if (event->irq_is_wake)
				disable_irq_wake(event->irq);

			free_irq(event->irq, event);
		}

		gpiochip_unlock_as_irq(chip, event->pin);
		gpiochip_free_own_desc(event->desc);
		list_del(&event->node);
		kfree(event);
	}
}
EXPORT_SYMBOL_GPL(acpi_gpiochip_free_interrupts);

void __init acpi_gpio_process_deferred_list(struct list_head *list)
{
	struct acpi_gpio_chip *acpi_gpio, *tmp;

	list_for_each_entry_safe(acpi_gpio, tmp, list, deferred_req_irqs_list_entry)
		acpi_gpiochip_request_irqs(acpi_gpio);
}

int acpi_dev_add_driver_gpios(struct acpi_device *adev,
			      const struct acpi_gpio_mapping *gpios)
{
	if (adev && gpios) {
		adev->driver_gpios = gpios;
		return 0;
	}
	return -EINVAL;
}
EXPORT_SYMBOL_GPL(acpi_dev_add_driver_gpios);

void acpi_dev_remove_driver_gpios(struct acpi_device *adev)
{
	if (adev)
		adev->driver_gpios = NULL;
}
EXPORT_SYMBOL_GPL(acpi_dev_remove_driver_gpios);

static void acpi_dev_release_driver_gpios(void *adev)
{
	acpi_dev_remove_driver_gpios(adev);
}

int devm_acpi_dev_add_driver_gpios(struct device *dev,
				   const struct acpi_gpio_mapping *gpios)
{
	struct acpi_device *adev = ACPI_COMPANION(dev);
	int ret;

	ret = acpi_dev_add_driver_gpios(adev, gpios);
	if (ret)
		return ret;

	return devm_add_action_or_reset(dev, acpi_dev_release_driver_gpios, adev);
}
EXPORT_SYMBOL_GPL(devm_acpi_dev_add_driver_gpios);

static bool acpi_get_driver_gpio_data(struct acpi_device *adev,
				      const char *name, int index,
				      struct fwnode_reference_args *args,
				      unsigned int *quirks)
{
	const struct acpi_gpio_mapping *gm;

	if (!adev || !adev->driver_gpios)
		return false;

	for (gm = adev->driver_gpios; gm->name; gm++)
		if (!strcmp(name, gm->name) && gm->data && index < gm->size) {
			const struct acpi_gpio_params *params = gm->data + index;

			args->fwnode = acpi_fwnode_handle(adev);
			args->args[0] = params->crs_entry_index;
			args->args[1] = params->line_index;
			args->args[2] = params->active_low;
			args->nargs = 3;

			*quirks = gm->quirks;
			return true;
		}

	return false;
}

static int
__acpi_gpio_update_gpiod_flags(enum gpiod_flags *flags, enum gpiod_flags update)
{
	const enum gpiod_flags mask =
		GPIOD_FLAGS_BIT_DIR_SET | GPIOD_FLAGS_BIT_DIR_OUT |
		GPIOD_FLAGS_BIT_DIR_VAL;
	int ret = 0;

	/*
	 * Check if the BIOS has IoRestriction with explicitly set direction
	 * and update @flags accordingly. Otherwise use whatever caller asked
	 * for.
	 */
	if (update & GPIOD_FLAGS_BIT_DIR_SET) {
		enum gpiod_flags diff = *flags ^ update;

		/*
		 * Check if caller supplied incompatible GPIO initialization
		 * flags.
		 *
		 * Return %-EINVAL to notify that firmware has different
		 * settings and we are going to use them.
		 */
		if (((*flags & GPIOD_FLAGS_BIT_DIR_SET) && (diff & GPIOD_FLAGS_BIT_DIR_OUT)) ||
		    ((*flags & GPIOD_FLAGS_BIT_DIR_OUT) && (diff & GPIOD_FLAGS_BIT_DIR_VAL)))
			ret = -EINVAL;
		*flags = (*flags & ~mask) | (update & mask);
	}
	return ret;
}

static int acpi_gpio_update_gpiod_flags(enum gpiod_flags *flags,
				        struct acpi_gpio_info *info)
{
	struct device *dev = &info->adev->dev;
	enum gpiod_flags old = *flags;
	int ret;

	ret = __acpi_gpio_update_gpiod_flags(&old, info->flags);
	if (info->quirks & ACPI_GPIO_QUIRK_NO_IO_RESTRICTION) {
		if (ret)
			dev_warn(dev, FW_BUG "GPIO not in correct mode, fixing\n");
	} else {
		if (ret)
			dev_dbg(dev, "Override GPIO initialization flags\n");
		*flags = old;
	}

	return ret;
}

static int acpi_gpio_update_gpiod_lookup_flags(unsigned long *lookupflags,
					       struct acpi_gpio_info *info)
{
	switch (info->pin_config) {
	case ACPI_PIN_CONFIG_PULLUP:
		*lookupflags |= GPIO_PULL_UP;
		break;
	case ACPI_PIN_CONFIG_PULLDOWN:
		*lookupflags |= GPIO_PULL_DOWN;
		break;
	case ACPI_PIN_CONFIG_NOPULL:
		*lookupflags |= GPIO_PULL_DISABLE;
		break;
	default:
		break;
	}

	if (info->polarity == GPIO_ACTIVE_LOW)
		*lookupflags |= GPIO_ACTIVE_LOW;

	return 0;
}

struct acpi_gpio_lookup {
	struct acpi_gpio_params params;
	struct acpi_gpio_info *info;
	struct gpio_desc *desc;
	int n;
};

static int acpi_populate_gpio_lookup(struct acpi_resource *ares, void *data)
{
	struct acpi_gpio_lookup *lookup = data;
	struct acpi_gpio_params *params = &lookup->params;
	struct acpi_gpio_info *info = lookup->info;

	if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
		return 1;

	if (!lookup->desc) {
		const struct acpi_resource_gpio *agpio = &ares->data.gpio;
		bool gpioint = agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
		struct gpio_desc *desc;
		u16 pin_index;

		if (info->quirks & ACPI_GPIO_QUIRK_ONLY_GPIOIO && gpioint)
			params->crs_entry_index++;

		if (lookup->n++ != params->crs_entry_index)
			return 1;

		pin_index = params->line_index;
		if (pin_index >= agpio->pin_table_length)
			return 1;

		if (info->quirks & ACPI_GPIO_QUIRK_ABSOLUTE_NUMBER)
			desc = gpio_to_desc(agpio->pin_table[pin_index]);
		else
			desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
					      agpio->pin_table[pin_index]);
		lookup->desc = desc;
		info->pin_config = agpio->pin_config;
		info->debounce = agpio->debounce_timeout;
		info->gpioint = gpioint;
		info->wake_capable = acpi_gpio_irq_is_wake(&info->adev->dev, agpio);

		/*
		 * Polarity and triggering are only specified for GpioInt
		 * resource.
		 * Note: we expect here:
		 * - ACPI_ACTIVE_LOW == GPIO_ACTIVE_LOW
		 * - ACPI_ACTIVE_HIGH == GPIO_ACTIVE_HIGH
		 */
		if (info->gpioint) {
			info->polarity = agpio->polarity;
			info->triggering = agpio->triggering;
		} else {
			info->polarity = params->active_low;
		}

		info->flags = acpi_gpio_to_gpiod_flags(agpio, info->polarity);
	}

	return 1;
}

static int acpi_gpio_resource_lookup(struct acpi_gpio_lookup *lookup)
{
	struct acpi_gpio_info *info = lookup->info;
	struct acpi_device *adev = info->adev;
	struct list_head res_list;
	int ret;

	INIT_LIST_HEAD(&res_list);

	ret = acpi_dev_get_resources(adev, &res_list,
				     acpi_populate_gpio_lookup,
				     lookup);
	if (ret < 0)
		return ret;

	acpi_dev_free_resource_list(&res_list);

	if (!lookup->desc)
		return -ENOENT;

	return 0;
}

static int acpi_gpio_property_lookup(struct fwnode_handle *fwnode, const char *propname,
				     struct acpi_gpio_lookup *lookup)
{
	struct fwnode_reference_args args;
	struct acpi_gpio_params *params = &lookup->params;
	struct acpi_gpio_info *info = lookup->info;
	unsigned int index = params->crs_entry_index;
	unsigned int quirks = 0;
	int ret;

	memset(&args, 0, sizeof(args));

	ret = __acpi_node_get_property_reference(fwnode, propname, index, 3, &args);
	if (ret) {
		struct acpi_device *adev;

		adev = to_acpi_device_node(fwnode);
		if (!acpi_get_driver_gpio_data(adev, propname, index, &args, &quirks))
			return ret;
	}
	/*
	 * The property was found and resolved, so need to lookup the GPIO based
	 * on returned args.
	 */
	if (!to_acpi_device_node(args.fwnode))
		return -EINVAL;
	if (args.nargs != 3)
		return -EPROTO;

	params->crs_entry_index = args.args[0];
	params->line_index = args.args[1];
	params->active_low = !!args.args[2];

	info->adev = to_acpi_device_node(args.fwnode);
	info->quirks = quirks;

	return 0;
}

/**
 * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
 * @adev: pointer to a ACPI device to get GPIO from
 * @propname: Property name of the GPIO (optional)
 * @lookup: pointer to struct acpi_gpio_lookup to fill in
 *
 * Function goes through ACPI resources for @adev and based on @lookup.index looks
 * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
 * and returns it. @lookup.index matches GpioIo/GpioInt resources only so if there
 * are total 3 GPIO resources, the index goes from 0 to 2.
 *
 * If @propname is specified the GPIO is looked using device property. In
 * that case @index is used to select the GPIO entry in the property value
 * (in case of multiple).
 *
 * Returns:
 * 0 on success, negative errno on failure.
 *
 * The @lookup is filled with GPIO descriptor to use with Linux generic GPIO API.
 * If the GPIO cannot be translated an error will be returned.
 *
 * Note: if the GPIO resource has multiple entries in the pin list, this
 * function only returns the first.
 */
static int acpi_get_gpiod_by_index(struct acpi_device *adev, const char *propname,
				   struct acpi_gpio_lookup *lookup)
{
	struct acpi_gpio_params *params = &lookup->params;
	struct acpi_gpio_info *info = lookup->info;
	int ret;

	if (propname) {
		dev_dbg(&adev->dev, "GPIO: looking up %s\n", propname);

		ret = acpi_gpio_property_lookup(acpi_fwnode_handle(adev), propname, lookup);
		if (ret)
			return ret;

		dev_dbg(&adev->dev, "GPIO: _DSD returned %s %u %u %u\n",
			dev_name(&info->adev->dev),
			params->crs_entry_index, params->line_index, params->active_low);
	} else {
		dev_dbg(&adev->dev, "GPIO: looking up %u in _CRS\n", params->crs_entry_index);
		info->adev = adev;
	}

	return acpi_gpio_resource_lookup(lookup);
}

/**
 * acpi_get_gpiod_from_data() - get a GPIO descriptor from ACPI data node
 * @fwnode: pointer to an ACPI firmware node to get the GPIO information from
 * @propname: Property name of the GPIO
 * @lookup: pointer to struct acpi_gpio_lookup to fill in
 *
 * This function uses the property-based GPIO lookup to get to the GPIO
 * resource with the relevant information from a data-only ACPI firmware node
 * and uses that to obtain the GPIO descriptor to return.
 *
 * Returns:
 * 0 on success, negative errno on failure.
 *
 * The @lookup is filled with GPIO descriptor to use with Linux generic GPIO API.
 * If the GPIO cannot be translated an error will be returned.
 */
static int acpi_get_gpiod_from_data(struct fwnode_handle *fwnode, const char *propname,
				    struct acpi_gpio_lookup *lookup)
{
	int ret;

	if (!is_acpi_data_node(fwnode))
		return -ENODEV;

	if (!propname)
		return -EINVAL;

	ret = acpi_gpio_property_lookup(fwnode, propname, lookup);
	if (ret)
		return ret;

	return acpi_gpio_resource_lookup(lookup);
}

static bool acpi_can_fallback_to_crs(struct acpi_device *adev,
				     const char *con_id)
{
	/* If there is no ACPI device, there is no _CRS to fall back to */
	if (!adev)
		return false;

	/* Never allow fallback if the device has properties */
	if (acpi_dev_has_props(adev) || adev->driver_gpios)
		return false;

	return con_id == NULL;
}

static struct gpio_desc *
__acpi_find_gpio(struct fwnode_handle *fwnode, const char *con_id, unsigned int idx,
		 bool can_fallback, struct acpi_gpio_info *info)
{
	struct acpi_device *adev = to_acpi_device_node(fwnode);
	struct acpi_gpio_lookup lookup;
	struct gpio_desc *desc;
	char propname[32];
	int ret;

	memset(&lookup, 0, sizeof(lookup));
	lookup.params.crs_entry_index = idx;
	lookup.info = info;

	/* Try first from _DSD */
	for_each_gpio_property_name(propname, con_id) {
		if (adev)
			ret = acpi_get_gpiod_by_index(adev, propname, &lookup);
		else
			ret = acpi_get_gpiod_from_data(fwnode, propname, &lookup);
		if (ret)
			continue;

		desc = lookup.desc;
		if (PTR_ERR(desc) == -EPROBE_DEFER)
			return desc;

		if (!IS_ERR(desc))
			return desc;
	}

	/* Then from plain _CRS GPIOs */
	if (can_fallback) {
		ret = acpi_get_gpiod_by_index(adev, NULL, &lookup);
		if (ret)
			return ERR_PTR(ret);

		return lookup.desc;
	}

	return ERR_PTR(-ENOENT);
}

struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
				 const char *con_id,
				 unsigned int idx,
				 enum gpiod_flags *dflags,
				 unsigned long *lookupflags)
{
	struct acpi_device *adev = to_acpi_device_node(fwnode);
	bool can_fallback = acpi_can_fallback_to_crs(adev, con_id);
	struct acpi_gpio_info info = {};
	struct gpio_desc *desc;

	desc = __acpi_find_gpio(fwnode, con_id, idx, can_fallback, &info);
	if (IS_ERR(desc))
		return desc;

	if (info.gpioint &&
	    (*dflags == GPIOD_OUT_LOW || *dflags == GPIOD_OUT_HIGH)) {
		dev_dbg(&adev->dev, "refusing GpioInt() entry when doing GPIOD_OUT_* lookup\n");
		return ERR_PTR(-ENOENT);
	}

	acpi_gpio_update_gpiod_flags(dflags, &info);
	acpi_gpio_update_gpiod_lookup_flags(lookupflags, &info);

	acpi_gpio_set_debounce_timeout(desc, info.debounce);

	return desc;
}

/**
 * acpi_dev_gpio_irq_wake_get_by() - Find GpioInt and translate it to Linux IRQ number
 * @adev: pointer to a ACPI device to get IRQ from
 * @con_id: optional name of GpioInt resource
 * @index: index of GpioInt resource (starting from %0)
 * @wake_capable: Set to true if the IRQ is wake capable
 *
 * If the device has one or more GpioInt resources, this function can be
 * used to translate from the GPIO offset in the resource to the Linux IRQ
 * number.
 *
 * The function is idempotent, though each time it runs it will configure GPIO
 * pin direction according to the flags in GpioInt resource.
 *
 * The function takes optional @con_id parameter. If the resource has
 * a @con_id in a property, then only those will be taken into account.
 *
 * The GPIO is considered wake capable if the GpioInt resource specifies
 * SharedAndWake or ExclusiveAndWake.
 *
 * Returns:
 * Linux IRQ number (> 0) on success, negative errno on failure.
 */
int acpi_dev_gpio_irq_wake_get_by(struct acpi_device *adev, const char *con_id, int index,
				  bool *wake_capable)
{
	struct fwnode_handle *fwnode = acpi_fwnode_handle(adev);
	int idx, i;
	unsigned int irq_flags;
	int ret;

	for (i = 0, idx = 0; idx <= index; i++) {
		struct acpi_gpio_info info = {};
		struct gpio_desc *desc;

		/* Ignore -EPROBE_DEFER, it only matters if idx matches */
		desc = __acpi_find_gpio(fwnode, con_id, i, true, &info);
		if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER)
			return PTR_ERR(desc);

		if (info.gpioint && idx++ == index) {
			unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
			enum gpiod_flags dflags = GPIOD_ASIS;
			char label[32];
			int irq;

			if (IS_ERR(desc))
				return PTR_ERR(desc);

			irq = gpiod_to_irq(desc);
			if (irq < 0)
				return irq;

			acpi_gpio_update_gpiod_flags(&dflags, &info);
			acpi_gpio_update_gpiod_lookup_flags(&lflags, &info);

			snprintf(label, sizeof(label), "%pfwP GpioInt(%d)", fwnode, index);
			ret = gpiod_set_consumer_name(desc, con_id ?: label);
			if (ret)
				return ret;

			ret = gpiod_configure_flags(desc, label, lflags, dflags);
			if (ret < 0)
				return ret;

			/* ACPI uses hundredths of milliseconds units */
			ret = gpio_set_debounce_timeout(desc, info.debounce * 10);
			if (ret)
				return ret;

			irq_flags = acpi_dev_get_irq_type(info.triggering,
							  info.polarity);

			/*
			 * If the IRQ is not already in use then set type
			 * if specified and different than the current one.
			 */
			if (can_request_irq(irq, irq_flags)) {
				if (irq_flags != IRQ_TYPE_NONE &&
				    irq_flags != irq_get_trigger_type(irq))
					irq_set_irq_type(irq, irq_flags);
			} else {
				dev_dbg(&adev->dev, "IRQ %d already in use\n", irq);
			}

			/* avoid suspend issues with GPIOs when systems are using S3 */
			if (wake_capable && acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)
				*wake_capable = info.wake_capable;

			return irq;
		}

	}
	return -ENOENT;
}
EXPORT_SYMBOL_GPL(acpi_dev_gpio_irq_wake_get_by);

static acpi_status
acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
			    u32 bits, u64 *value, void *handler_context,
			    void *region_context)
{
	struct acpi_gpio_chip *achip = region_context;
	struct gpio_chip *chip = achip->chip;
	struct acpi_resource_gpio *agpio;
	struct acpi_resource *ares;
	u16 pin_index = address;
	acpi_status status;
	int length;
	int i;

	status = acpi_buffer_to_resource(achip->conn_info.connection,
					 achip->conn_info.length, &ares);
	if (ACPI_FAILURE(status))
		return status;

	if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) {
		ACPI_FREE(ares);
		return AE_BAD_PARAMETER;
	}

	agpio = &ares->data.gpio;

	if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT &&
	    function == ACPI_WRITE)) {
		ACPI_FREE(ares);
		return AE_BAD_PARAMETER;
	}

	length = min(agpio->pin_table_length, pin_index + bits);
	for (i = pin_index; i < length; ++i) {
		unsigned int pin = agpio->pin_table[i];
		struct acpi_gpio_connection *conn;
		struct gpio_desc *desc;
		u16 word, shift;
		bool found;

		mutex_lock(&achip->conn_lock);

		found = false;
		list_for_each_entry(conn, &achip->conns, node) {
			if (conn->pin == pin) {
				found = true;
				desc = conn->desc;
				break;
			}
		}

		/*
		 * The same GPIO can be shared between operation region and
		 * event but only if the access here is ACPI_READ. In that
		 * case we "borrow" the event GPIO instead.
		 */
		if (!found && agpio->shareable == ACPI_SHARED &&
		     function == ACPI_READ) {
			struct acpi_gpio_event *event;

			list_for_each_entry(event, &achip->events, node) {
				if (event->pin == pin) {
					desc = event->desc;
					found = true;
					break;
				}
			}
		}

		if (!found) {
			desc = acpi_request_own_gpiod(chip, agpio, i, "ACPI:OpRegion");
			if (IS_ERR(desc)) {
				mutex_unlock(&achip->conn_lock);
				status = AE_ERROR;
				goto out;
			}

			conn = kzalloc_obj(*conn);
			if (!conn) {
				gpiochip_free_own_desc(desc);
				mutex_unlock(&achip->conn_lock);
				status = AE_NO_MEMORY;
				goto out;
			}

			conn->pin = pin;
			conn->desc = desc;
			list_add_tail(&conn->node, &achip->conns);
		}

		mutex_unlock(&achip->conn_lock);

		/*
		 * For the cases when OperationRegion() consists of more than
		 * 64 bits calculate the word and bit shift to use that one to
		 * access the value.
		 */
		word = i / 64;
		shift = i % 64;

		if (function == ACPI_WRITE) {
			gpiod_set_raw_value_cansleep(desc, value[word] & BIT_ULL(shift));
		} else {
			if (gpiod_get_raw_value_cansleep(desc))
				value[word] |= BIT_ULL(shift);
			else
				value[word] &= ~BIT_ULL(shift);
		}
	}

out:
	ACPI_FREE(ares);
	return status;
}

static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip)
{
	struct gpio_chip *chip = achip->chip;
	acpi_handle handle = ACPI_HANDLE(chip->parent);
	acpi_status status;

	INIT_LIST_HEAD(&achip->conns);
	mutex_init(&achip->conn_lock);
	status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
						    acpi_gpio_adr_space_handler,
						    NULL, achip);
	if (ACPI_FAILURE(status))
		dev_err(chip->parent,
		        "Failed to install GPIO OpRegion handler\n");
}

static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
{
	struct gpio_chip *chip = achip->chip;
	acpi_handle handle = ACPI_HANDLE(chip->parent);
	struct acpi_gpio_connection *conn, *tmp;
	acpi_status status;

	status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
						   acpi_gpio_adr_space_handler);
	if (ACPI_FAILURE(status)) {
		dev_err(chip->parent,
			"Failed to remove GPIO OpRegion handler\n");
		return;
	}

	list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) {
		gpiochip_free_own_desc(conn->desc);
		list_del(&conn->node);
		kfree(conn);
	}
}

static struct gpio_desc *
acpi_gpiochip_parse_own_gpio(struct acpi_gpio_chip *achip,
			     struct fwnode_handle *fwnode,
			     const char **name,
			     unsigned long *lflags,
			     enum gpiod_flags *dflags)
{
	struct gpio_chip *chip = achip->chip;
	struct gpio_desc *desc;
	u32 gpios[2];
	int ret;

	*lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
	*dflags = GPIOD_ASIS;
	*name = NULL;

	ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios,
					     ARRAY_SIZE(gpios));
	if (ret < 0)
		return ERR_PTR(ret);

	desc = gpiochip_get_desc(chip, gpios[0]);
	if (IS_ERR(desc))
		return desc;

	if (gpios[1])
		*lflags |= GPIO_ACTIVE_LOW;

	if (fwnode_property_present(fwnode, "input"))
		*dflags |= GPIOD_IN;
	else if (fwnode_property_present(fwnode, "output-low"))
		*dflags |= GPIOD_OUT_LOW;
	else if (fwnode_property_present(fwnode, "output-high"))
		*dflags |= GPIOD_OUT_HIGH;
	else
		return ERR_PTR(-EINVAL);

	fwnode_property_read_string(fwnode, "line-name", name);

	return desc;
}

static void acpi_gpiochip_scan_gpios(struct acpi_gpio_chip *achip)
{
	struct gpio_chip *chip = achip->chip;

	device_for_each_child_node_scoped(chip->parent, fwnode) {
		unsigned long lflags;
		enum gpiod_flags dflags;
		struct gpio_desc *desc;
		const char *name;
		int ret;

		if (!fwnode_property_present(fwnode, "gpio-hog"))
			continue;

		desc = acpi_gpiochip_parse_own_gpio(achip, fwnode, &name,
						    &lflags, &dflags);
		if (IS_ERR(desc))
			continue;

		ret = gpiod_hog(desc, name, lflags, dflags);
		if (ret) {
			dev_err(chip->parent, "Failed to hog GPIO\n");
			return;
		}
	}
}

void acpi_gpiochip_add(struct gpio_chip *chip)
{
	struct acpi_gpio_chip *acpi_gpio;
	struct acpi_device *adev;
	acpi_status status;

	if (!chip || !chip->parent)
		return;

	adev = ACPI_COMPANION(chip->parent);
	if (!adev)
		return;

	acpi_gpio = kzalloc_obj(*acpi_gpio);
	if (!acpi_gpio) {
		dev_err(chip->parent,
			"Failed to allocate memory for ACPI GPIO chip\n");
		return;
	}

	acpi_gpio->chip = chip;
	INIT_LIST_HEAD(&acpi_gpio->events);
	INIT_LIST_HEAD(&acpi_gpio->deferred_req_irqs_list_entry);

	status = acpi_attach_data(adev->handle, acpi_gpio_chip_dh, acpi_gpio);
	if (ACPI_FAILURE(status)) {
		dev_err(chip->parent, "Failed to attach ACPI GPIO chip\n");
		kfree(acpi_gpio);
		return;
	}

	acpi_gpiochip_request_regions(acpi_gpio);
	acpi_gpiochip_scan_gpios(acpi_gpio);
	acpi_dev_clear_dependencies(adev);
}

void acpi_gpiochip_remove(struct gpio_chip *chip)
{
	struct acpi_gpio_chip *acpi_gpio;
	acpi_handle handle;
	acpi_status status;

	if (!chip || !chip->parent)
		return;

	handle = ACPI_HANDLE(chip->parent);
	if (!handle)
		return;

	status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
	if (ACPI_FAILURE(status)) {
		dev_warn(chip->parent, "Failed to retrieve ACPI GPIO chip\n");
		return;
	}

	acpi_gpiochip_free_regions(acpi_gpio);

	acpi_detach_data(handle, acpi_gpio_chip_dh);
	kfree(acpi_gpio);
}

static int acpi_gpio_package_count(const union acpi_object *obj)
{
	const union acpi_object *element = obj->package.elements;
	const union acpi_object *end = element + obj->package.count;
	unsigned int count = 0;

	while (element < end) {
		switch (element->type) {
		case ACPI_TYPE_LOCAL_REFERENCE:
		case ACPI_TYPE_STRING:
			element += 3;
			fallthrough;
		case ACPI_TYPE_INTEGER:
			element++;
			count++;
			break;

		default:
			return -EPROTO;
		}
	}

	return count;
}

static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
{
	unsigned int *count = data;

	if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
		*count += ares->data.gpio.pin_table_length;

	return 1;
}

/**
 * acpi_gpio_count - count the GPIOs associated with a firmware node / function
 * @fwnode:	firmware node of the GPIO consumer
 * @con_id:	function within the GPIO consumer
 *
 * Returns:
 * The number of GPIOs associated with a firmware node / function or %-ENOENT,
 * if no GPIO has been assigned to the requested function.
 */
int acpi_gpio_count(const struct fwnode_handle *fwnode, const char *con_id)
{
	struct acpi_device *adev = to_acpi_device_node(fwnode);
	const union acpi_object *obj;
	const struct acpi_gpio_mapping *gm;
	int count = -ENOENT;
	int ret;
	char propname[32];

	/* Try first from _DSD */
	for_each_gpio_property_name(propname, con_id) {
		ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY, &obj);
		if (ret == 0) {
			if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
				count = 1;
			else if (obj->type == ACPI_TYPE_PACKAGE)
				count = acpi_gpio_package_count(obj);
		} else if (adev->driver_gpios) {
			for (gm = adev->driver_gpios; gm->name; gm++)
				if (strcmp(propname, gm->name) == 0) {
					count = gm->size;
					break;
				}
		}
		if (count > 0)
			break;
	}

	/* Then from plain _CRS GPIOs */
	if (count < 0) {
		struct list_head resource_list;
		unsigned int crs_count = 0;

		if (!acpi_can_fallback_to_crs(adev, con_id))
			return count;

		INIT_LIST_HEAD(&resource_list);
		acpi_dev_get_resources(adev, &resource_list,
				       acpi_find_gpio_count, &crs_count);
		acpi_dev_free_resource_list(&resource_list);
		if (crs_count > 0)
			count = crs_count;
	}
	return count ? count : -ENOENT;
}