drivers/gpio/gpiolib-acpi.c - kernel/msm-4.9 - Gitiles

 /*
  * 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>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/errno.h>
 #include <linux/gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/gpio/driver.h>
 #include <linux/export.h>
 #include <linux/acpi.h>
 #include <linux/interrupt.h>
 #include <linux/mutex.h>
 #include <linux/pinctrl/pinctrl.h>

 #include "gpiolib.h"

 struct acpi_gpio_event {
 	struct list_head node;
 	acpi_handle handle;
 	unsigned int pin;
 	unsigned int irq;
 	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;
 };

 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
 {
 	if (!gc->dev)
 		return false;

 	return ACPI_HANDLE(gc->dev) == data;
 }

 #ifdef CONFIG_PINCTRL
 /**
  * acpi_gpiochip_pin_to_gpio_offset() - translates ACPI GPIO to Linux GPIO
  * @chip: GPIO chip
  * @pin: ACPI GPIO pin number from GpioIo/GpioInt resource
  *
  * Function takes ACPI GpioIo/GpioInt pin number as a parameter and
  * translates it to a corresponding offset suitable to be passed to a
  * GPIO controller driver.
  *
  * Typically the returned offset is same as @pin, but if the GPIO
  * controller uses pin controller and the mapping is not contigous the
  * offset might be different.
  */
 static int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip, int pin)
 {
 	struct gpio_pin_range *pin_range;

 	/* If there are no ranges in this chip, use 1:1 mapping */
 	if (list_empty(&chip->pin_ranges))
 		return pin;

 	list_for_each_entry(pin_range, &chip->pin_ranges, node) {
 		const struct pinctrl_gpio_range *range = &pin_range->range;
 		int i;

 		if (range->pins) {
 			for (i = 0; i < range->npins; i++) {
 				if (range->pins[i] == pin)
 					return range->base + i - chip->base;
 			}
 		} else {
 			if (pin >= range->pin_base &&
 			    pin < range->pin_base + range->npins) {
 				unsigned gpio_base;

 				gpio_base = range->base - chip->base;
 				return gpio_base + pin - range->pin_base;
 			}
 		}
 	}

 	return -EINVAL;
 }
 #else
 static inline int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip,
 						   int pin)
 {
 	return pin;
 }
 #endif

 /**
  * 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, or ERR_PTR
  * error value
  */

 static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
 {
 	struct gpio_chip *chip;
 	acpi_handle handle;
 	acpi_status status;
 	int offset;

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

 	chip = gpiochip_find(handle, acpi_gpiochip_find);
 	if (!chip)
 		return ERR_PTR(-ENODEV);

 	offset = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 	if (offset < 0)
 		return ERR_PTR(offset);

 	return gpiochip_get_desc(chip, offset);
 }

 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. */
 }

 static acpi_status acpi_gpiochip_request_interrupt(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 long irqflags;
 	int ret, pin, irq;

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

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

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

 	if (pin <= 255) {
 		char ev_name[5];
 		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_BAD_PARAMETER;

 	pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 	if (pin < 0)
 		return AE_BAD_PARAMETER;

 	desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
 	if (IS_ERR(desc)) {
 		dev_err(chip->dev, "Failed to request GPIO\n");
 		return AE_ERROR;
 	}

 	gpiod_direction_input(desc);

 	ret = gpiochip_lock_as_irq(chip, pin);
 	if (ret) {
 		dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
 		goto fail_free_desc;
 	}

 	irq = gpiod_to_irq(desc);
 	if (irq < 0) {
 		dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
 		goto fail_unlock_irq;
 	}

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

 	event = kzalloc(sizeof(*event), GFP_KERNEL);
 	if (!event)
 		goto fail_unlock_irq;

 	event->handle = evt_handle;
 	event->irq = irq;
 	event->pin = pin;
 	event->desc = desc;

 	ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
 				   "ACPI:Event", event);
 	if (ret) {
 		dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
 			event->irq);
 		goto fail_free_event;
 	}

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

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

 	return AE_ERROR;
 }

 /**
  * 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->dev || !chip->to_irq)
 		return;

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

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

 	INIT_LIST_HEAD(&acpi_gpio->events);
 	acpi_walk_resources(handle, "_AEI",
 			    acpi_gpiochip_request_interrupt, acpi_gpio);
 }

 /**
  * 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->dev || !chip->to_irq)
 		return;

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

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

 	list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
 		struct gpio_desc *desc;

 		free_irq(event->irq, event);
 		desc = event->desc;
 		if (WARN_ON(IS_ERR(desc)))
 			continue;
 		gpiochip_unlock_as_irq(chip, event->pin);
 		gpiochip_free_own_desc(desc);
 		list_del(&event->node);
 		kfree(event);
 	}
 }

 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);

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

 	if (!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 *par = gm->data + index;

 			args->adev = adev;
 			args->args[0] = par->crs_entry_index;
 			args->args[1] = par->line_index;
 			args->args[2] = par->active_low;
 			args->nargs = 3;
 			return true;
 		}

 	return false;
 }

 struct acpi_gpio_lookup {
 	struct acpi_gpio_info info;
 	int index;
 	int pin_index;
 	struct gpio_desc *desc;
 	int n;
 };

 static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 {
 	struct acpi_gpio_lookup *lookup = data;

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

 	if (lookup->n++ == lookup->index && !lookup->desc) {
 		const struct acpi_resource_gpio *agpio = &ares->data.gpio;
 		int pin_index = lookup->pin_index;

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

 		lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
 					      agpio->pin_table[pin_index]);
 		lookup->info.gpioint =
 			agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;

 		/*
 		 * ActiveLow is only specified for GpioInt resource. If
 		 * GpioIo is used then the only way to set the flag is
 		 * to use _DSD "gpios" property.
 		 */
 		if (lookup->info.gpioint)
 			lookup->info.active_low =
 				agpio->polarity == ACPI_ACTIVE_LOW;
 	}

 	return 1;
 }

 /**
  * 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)
  * @index: index of GpioIo/GpioInt resource (starting from %0)
  * @info: info pointer to fill in (optional)
  *
  * Function goes through ACPI resources for @adev and based on @index looks
  * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
  * and returns it. @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).
  *
  * If the GPIO cannot be translated or there is an error an ERR_PTR is
  * returned.
  *
  * Note: if the GPIO resource has multiple entries in the pin list, this
  * function only returns the first.
  */
 struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
 					  const char *propname, int index,
 					  struct acpi_gpio_info *info)
 {
 	struct acpi_gpio_lookup lookup;
 	struct list_head resource_list;
 	bool active_low = false;
 	int ret;

 	if (!adev)
 		return ERR_PTR(-ENODEV);

 	memset(&lookup, 0, sizeof(lookup));
 	lookup.index = index;

 	if (propname) {
 		struct acpi_reference_args args;

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

 		memset(&args, 0, sizeof(args));
 		ret = acpi_dev_get_property_reference(adev, propname,
 						      index, &args);
 		if (ret) {
 			bool found = acpi_get_driver_gpio_data(adev, propname,
 							       index, &args);
 			if (!found)
 				return ERR_PTR(ret);
 		}

 		/*
 		 * The property was found and resolved so need to
 		 * lookup the GPIO based on returned args instead.
 		 */
 		adev = args.adev;
 		if (args.nargs >= 2) {
 			lookup.index = args.args[0];
 			lookup.pin_index = args.args[1];
 			/*
 			 * 3rd argument, if present is used to
 			 * specify active_low.
 			 */
 			if (args.nargs >= 3)
 				active_low = !!args.args[2];
 		}

 		dev_dbg(&adev->dev, "GPIO: _DSD returned %s %zd %llu %llu %llu\n",
 			dev_name(&adev->dev), args.nargs,
 			args.args[0], args.args[1], args.args[2]);
 	} else {
 		dev_dbg(&adev->dev, "GPIO: looking up %d in _CRS\n", index);
 	}

 	INIT_LIST_HEAD(&resource_list);
 	ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
 				     &lookup);
 	if (ret < 0)
 		return ERR_PTR(ret);

 	acpi_dev_free_resource_list(&resource_list);

 	if (lookup.desc && info) {
 		*info = lookup.info;
 		if (active_low)
 			info->active_low = active_low;
 	}

 	return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
 }

 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;
 	int pin_index = (int)address;
 	acpi_status status;
 	bool pull_up;
 	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;
 	pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;

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

 		pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 		if (pin < 0) {
 			status = AE_BAD_PARAMETER;
 			goto out;
 		}

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

 			switch (agpio->io_restriction) {
 			case ACPI_IO_RESTRICT_INPUT:
 				gpiod_direction_input(desc);
 				break;
 			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
 				 * instead. If the pin is pulled up we
 				 * assume default to be high, otherwise
 				 * low.
 				 */
 				gpiod_direction_output(desc, pull_up);
 				break;
 			default:
 				/*
 				 * Assume that the BIOS has configured the
 				 * direction and pull accordingly.
 				 */
 				break;
 			}

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

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

 		mutex_unlock(&achip->conn_lock);

 		if (function == ACPI_WRITE)
 			gpiod_set_raw_value_cansleep(desc,
 						     !!((1 << i) & *value));
 		else
 			*value |= (u64)gpiod_get_raw_value_cansleep(desc) << i;
 	}

 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->dev);
 	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->dev, "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->dev);
 	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->dev, "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);
 	}
 }

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

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

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

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

 	acpi_gpio->chip = chip;

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

 	acpi_gpiochip_request_regions(acpi_gpio);
 }

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

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

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

 	status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 	if (ACPI_FAILURE(status)) {
 		dev_warn(chip->dev, "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 unsigned 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) {
 		if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
 			count++;

 		element++;
 	}
 	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 - 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 acpi_gpio_count(struct device *dev, const char *con_id)
 {
 	struct acpi_device *adev = ACPI_COMPANION(dev);
 	const union acpi_object *obj;
 	const struct acpi_gpio_mapping *gm;
 	int count = -ENOENT;
 	int ret;
 	char propname[32];
 	unsigned 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]);

 		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;

 		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;
 }
	/*
	* 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>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/errno.h>
	#include <linux/gpio.h>
	#include <linux/gpio/consumer.h>
	#include <linux/gpio/driver.h>
	#include <linux/export.h>
	#include <linux/acpi.h>
	#include <linux/interrupt.h>
	#include <linux/mutex.h>
	#include <linux/pinctrl/pinctrl.h>

	#include "gpiolib.h"

	struct acpi_gpio_event {
	struct list_head node;
	acpi_handle handle;
	unsigned int pin;
	unsigned int irq;
	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;
	};

	static int acpi_gpiochip_find(struct gpio_chip gc, void data)
	{
	if (!gc->dev)
	return false;

	return ACPI_HANDLE(gc->dev) == data;
	}

	#ifdef CONFIG_PINCTRL
	/**
	* acpi_gpiochip_pin_to_gpio_offset() - translates ACPI GPIO to Linux GPIO
	* @chip: GPIO chip
	* @pin: ACPI GPIO pin number from GpioIo/GpioInt resource
	*
	* Function takes ACPI GpioIo/GpioInt pin number as a parameter and
	* translates it to a corresponding offset suitable to be passed to a
	* GPIO controller driver.
	*
	* Typically the returned offset is same as @pin, but if the GPIO
	* controller uses pin controller and the mapping is not contigous the
	* offset might be different.
	*/
	static int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip, int pin)
	{
	struct gpio_pin_range *pin_range;

	/* If there are no ranges in this chip, use 1:1 mapping */
	if (list_empty(&chip->pin_ranges))
	return pin;

	list_for_each_entry(pin_range, &chip->pin_ranges, node) {
	const struct pinctrl_gpio_range *range = &pin_range->range;
	int i;

	if (range->pins) {
	for (i = 0; i < range->npins; i++) {
	if (range->pins[i] == pin)
	return range->base + i - chip->base;
	}
	} else {
	if (pin >= range->pin_base &&
	pin < range->pin_base + range->npins) {
	unsigned gpio_base;

	gpio_base = range->base - chip->base;
	return gpio_base + pin - range->pin_base;
	}
	}
	}

	return -EINVAL;
	}
	#else
	static inline int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip,
	int pin)
	{
	return pin;
	}
	#endif

	/**
	* 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, or ERR_PTR
	* error value
	*/

	static struct gpio_desc acpi_get_gpiod(char path, int pin)
	{
	struct gpio_chip *chip;
	acpi_handle handle;
	acpi_status status;
	int offset;

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

	chip = gpiochip_find(handle, acpi_gpiochip_find);
	if (!chip)
	return ERR_PTR(-ENODEV);

	offset = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
	if (offset < 0)
	return ERR_PTR(offset);

	return gpiochip_get_desc(chip, offset);
	}

	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. */
	}

	static acpi_status acpi_gpiochip_request_interrupt(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 long irqflags;
	int ret, pin, irq;

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

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

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

	if (pin <= 255) {
	char ev_name[5];
	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_BAD_PARAMETER;

	pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
	if (pin < 0)
	return AE_BAD_PARAMETER;

	desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
	if (IS_ERR(desc)) {
	dev_err(chip->dev, "Failed to request GPIO\n");
	return AE_ERROR;
	}

	gpiod_direction_input(desc);

	ret = gpiochip_lock_as_irq(chip, pin);
	if (ret) {
	dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
	goto fail_free_desc;
	}

	irq = gpiod_to_irq(desc);
	if (irq < 0) {
	dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
	goto fail_unlock_irq;
	}

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

	event = kzalloc(sizeof(*event), GFP_KERNEL);
	if (!event)
	goto fail_unlock_irq;

	event->handle = evt_handle;
	event->irq = irq;
	event->pin = pin;
	event->desc = desc;

	ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
	"ACPI:Event", event);
	if (ret) {
	dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
	event->irq);
	goto fail_free_event;
	}

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

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

	return AE_ERROR;
	}

	/**
	* 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->dev \|\| !chip->to_irq)
	return;

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

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

	INIT_LIST_HEAD(&acpi_gpio->events);
	acpi_walk_resources(handle, "_AEI",
	acpi_gpiochip_request_interrupt, acpi_gpio);
	}

	/**
	* 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->dev \|\| !chip->to_irq)
	return;

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

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

	list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
	struct gpio_desc *desc;

	free_irq(event->irq, event);
	desc = event->desc;
	if (WARN_ON(IS_ERR(desc)))
	continue;
	gpiochip_unlock_as_irq(chip, event->pin);
	gpiochip_free_own_desc(desc);
	list_del(&event->node);
	kfree(event);
	}
	}

	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);

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

	if (!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 *par = gm->data + index;

	args->adev = adev;
	args->args[0] = par->crs_entry_index;
	args->args[1] = par->line_index;
	args->args[2] = par->active_low;
	args->nargs = 3;
	return true;
	}

	return false;
	}

	struct acpi_gpio_lookup {
	struct acpi_gpio_info info;
	int index;
	int pin_index;
	struct gpio_desc *desc;
	int n;
	};

	static int acpi_find_gpio(struct acpi_resource ares, void data)
	{
	struct acpi_gpio_lookup *lookup = data;

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

	if (lookup->n++ == lookup->index && !lookup->desc) {
	const struct acpi_resource_gpio *agpio = &ares->data.gpio;
	int pin_index = lookup->pin_index;

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

	lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
	agpio->pin_table[pin_index]);
	lookup->info.gpioint =
	agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;

	/*
	* ActiveLow is only specified for GpioInt resource. If
	* GpioIo is used then the only way to set the flag is
	* to use _DSD "gpios" property.
	*/
	if (lookup->info.gpioint)
	lookup->info.active_low =
	agpio->polarity == ACPI_ACTIVE_LOW;
	}

	return 1;
	}

	/**
	* 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)
	* @index: index of GpioIo/GpioInt resource (starting from %0)
	* @info: info pointer to fill in (optional)
	*
	* Function goes through ACPI resources for @adev and based on @index looks
	* up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
	* and returns it. @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).
	*
	* If the GPIO cannot be translated or there is an error an ERR_PTR is
	* returned.
	*
	* Note: if the GPIO resource has multiple entries in the pin list, this
	* function only returns the first.
	*/
	struct gpio_desc acpi_get_gpiod_by_index(struct acpi_device adev,
	const char *propname, int index,
	struct acpi_gpio_info *info)
	{
	struct acpi_gpio_lookup lookup;
	struct list_head resource_list;
	bool active_low = false;
	int ret;

	if (!adev)
	return ERR_PTR(-ENODEV);

	memset(&lookup, 0, sizeof(lookup));
	lookup.index = index;

	if (propname) {
	struct acpi_reference_args args;

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

	memset(&args, 0, sizeof(args));
	ret = acpi_dev_get_property_reference(adev, propname,
	index, &args);
	if (ret) {
	bool found = acpi_get_driver_gpio_data(adev, propname,
	index, &args);
	if (!found)
	return ERR_PTR(ret);
	}

	/*
	* The property was found and resolved so need to
	* lookup the GPIO based on returned args instead.
	*/
	adev = args.adev;
	if (args.nargs >= 2) {
	lookup.index = args.args[0];
	lookup.pin_index = args.args[1];
	/*
	* 3rd argument, if present is used to
	* specify active_low.
	*/
	if (args.nargs >= 3)
	active_low = !!args.args[2];
	}

	dev_dbg(&adev->dev, "GPIO: _DSD returned %s %zd %llu %llu %llu\n",
	dev_name(&adev->dev), args.nargs,
	args.args[0], args.args[1], args.args[2]);
	} else {
	dev_dbg(&adev->dev, "GPIO: looking up %d in _CRS\n", index);
	}

	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
	&lookup);
	if (ret < 0)
	return ERR_PTR(ret);

	acpi_dev_free_resource_list(&resource_list);

	if (lookup.desc && info) {
	*info = lookup.info;
	if (active_low)
	info->active_low = active_low;
	}

	return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
	}

	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;
	int pin_index = (int)address;
	acpi_status status;
	bool pull_up;
	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;
	pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;

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

	pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
	if (pin < 0) {
	status = AE_BAD_PARAMETER;
	goto out;
	}

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

	switch (agpio->io_restriction) {
	case ACPI_IO_RESTRICT_INPUT:
	gpiod_direction_input(desc);
	break;
	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
	* instead. If the pin is pulled up we
	* assume default to be high, otherwise
	* low.
	*/
	gpiod_direction_output(desc, pull_up);
	break;
	default:
	/*
	* Assume that the BIOS has configured the
	* direction and pull accordingly.
	*/
	break;
	}

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

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

	mutex_unlock(&achip->conn_lock);

	if (function == ACPI_WRITE)
	gpiod_set_raw_value_cansleep(desc,
	!!((1 << i) & *value));
	else
	*value \|= (u64)gpiod_get_raw_value_cansleep(desc) << i;
	}

	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->dev);
	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->dev, "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->dev);
	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->dev, "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);
	}
	}

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

	if (!chip \|\| !chip->dev)
	return;

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

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

	acpi_gpio->chip = chip;

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

	acpi_gpiochip_request_regions(acpi_gpio);
	}

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

	if (!chip \|\| !chip->dev)
	return;

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

	status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
	if (ACPI_FAILURE(status)) {
	dev_warn(chip->dev, "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 unsigned 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) {
	if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
	count++;

	element++;
	}
	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 - 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 acpi_gpio_count(struct device dev, const char con_id)
	{
	struct acpi_device *adev = ACPI_COMPANION(dev);
	const union acpi_object *obj;
	const struct acpi_gpio_mapping *gm;
	int count = -ENOENT;
	int ret;
	char propname[32];
	unsigned 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]);

	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;

	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;
	}