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

static int run_edge_events_on_boot = -1;
module_param(run_edge_events_on_boot, int, 0444);
MODULE_PARM_DESC(run_edge_events_on_boot,
                 "Run edge _AEI event-handlers at boot: 0=no, 1=yes, -1=auto");

/**
 * 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;
};

/*
 * For GPIO chips which call acpi_gpiochip_request_interrupts() before late_init
 * (so builtin drivers) we register the ACPI GpioInt IRQ handlers from a
 * late_initcall_sync() handler, so that other builtin drivers can register their
 * OpRegions before the event handlers can run. This list contains GPIO chips
 * for which the acpi_gpiochip_request_irqs() call has been deferred.
 */
static DEFINE_MUTEX(acpi_gpio_deferred_req_irqs_lock);
static LIST_HEAD(acpi_gpio_deferred_req_irqs_list);
static bool acpi_gpio_deferred_req_irqs_done;

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

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

/**
 * 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)
 *
 * Return: GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
 * error value. 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, int pin)
{
        struct gpio_chip *chip;
        acpi_handle handle;
        acpi_status status;

        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(-EPROBE_DEFER);

        return gpiochip_get_desc(chip, 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);

static void acpi_gpiochip_request_irq(struct acpi_gpio_chip *acpi_gpio,
                                      struct acpi_gpio_event *event)
{
        int ret, value;

        ret = request_threaded_irq(event->irq, NULL, event->handler,
                                   event->irqflags, "ACPI:Event", event);
        if (ret) {
                dev_err(acpi_gpio->chip->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 (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 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;
        int ret, pin, 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[5];
                sprintf(ev_name, "_%c%02hhX",
                        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;

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

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

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

        event = kzalloc(sizeof(*event), GFP_KERNEL);
        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 = agpio->wake_capable == ACPI_WAKE_CAPABLE;
        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_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;
        bool defer;

        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_walk_resources(handle, "_AEI",
                            acpi_gpiochip_alloc_event, acpi_gpio);

        mutex_lock(&acpi_gpio_deferred_req_irqs_lock);
        defer = !acpi_gpio_deferred_req_irqs_done;
        if (defer)
                list_add(&acpi_gpio->deferred_req_irqs_list_entry,
                         &acpi_gpio_deferred_req_irqs_list);
        mutex_unlock(&acpi_gpio_deferred_req_irqs_lock);

        if (defer)
                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;

        mutex_lock(&acpi_gpio_deferred_req_irqs_lock);
        if (!list_empty(&acpi_gpio->deferred_req_irqs_list_entry))
                list_del_init(&acpi_gpio->deferred_req_irqs_list_entry);
        mutex_unlock(&acpi_gpio_deferred_req_irqs_lock);

        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);

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 void devm_acpi_dev_release_driver_gpios(struct device *dev, void *res)
{
        acpi_dev_remove_driver_gpios(ACPI_COMPANION(dev));
}

int devm_acpi_dev_add_driver_gpios(struct device *dev,
                                   const struct acpi_gpio_mapping *gpios)
{
        void *res;
        int ret;

        res = devres_alloc(devm_acpi_dev_release_driver_gpios, 0, GFP_KERNEL);
        if (!res)
                return -ENOMEM;

        ret = acpi_dev_add_driver_gpios(ACPI_COMPANION(dev), gpios);
        if (ret) {
                devres_free(res);
                return ret;
        }
        devres_add(dev, res);
        return 0;
}
EXPORT_SYMBOL_GPL(devm_acpi_dev_add_driver_gpios);

void devm_acpi_dev_remove_driver_gpios(struct device *dev)
{
        WARN_ON(devres_release(dev, devm_acpi_dev_release_driver_gpios, NULL, NULL));
}
EXPORT_SYMBOL_GPL(devm_acpi_dev_remove_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->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->fwnode = acpi_fwnode_handle(adev);
                        args->args[0] = par->crs_entry_index;
                        args->args[1] = par->line_index;
                        args->args[2] = par->active_low;
                        args->nargs = 3;

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

        return false;
}

static enum gpiod_flags
acpi_gpio_to_gpiod_flags(const struct acpi_resource_gpio *agpio)
{
        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
                 * 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.
                 */
                switch (agpio->pin_config) {
                case ACPI_PIN_CONFIG_PULLUP:
                        return GPIOD_OUT_HIGH;
                case ACPI_PIN_CONFIG_PULLDOWN:
                        return GPIOD_OUT_LOW;
                default:
                        break;
                }
        default:
                break;
        }

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

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;
}

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;
}

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;
        default:
                break;
        }

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

        return 0;
}

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

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

        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;
                int pin_index;

                if (lookup->info.quirks & ACPI_GPIO_QUIRK_ONLY_GPIOIO && gpioint)
                        lookup->index++;

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

                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.pin_config = agpio->pin_config;
                lookup->info.gpioint = gpioint;

                /*
                 * 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 (lookup->info.gpioint) {
                        lookup->info.flags = GPIOD_IN;
                        lookup->info.polarity = agpio->polarity;
                        lookup->info.triggering = agpio->triggering;
                } else {
                        lookup->info.flags = acpi_gpio_to_gpiod_flags(agpio);
                        lookup->info.polarity = lookup->active_low;
                }
        }

        return 1;
}

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

        if (info)
                *info = lookup->info;
        return 0;
}

static int acpi_gpio_property_lookup(struct fwnode_handle *fwnode,
                                     const char *propname, int index,
                                     struct acpi_gpio_lookup *lookup)
{
        struct fwnode_reference_args args;
        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 = to_acpi_device_node(fwnode);

                if (!adev)
                        return ret;

                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;

        lookup->index = args.args[0];
        lookup->pin_index = args.args[1];
        lookup->active_low = !!args.args[2];

        lookup->info.adev = to_acpi_device_node(args.fwnode);
        lookup->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)
 * @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.
 */
static 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;
        int ret;

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

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

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

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

                dev_dbg(&adev->dev, "GPIO: _DSD returned %s %d %d %u\n",
                        dev_name(&lookup.info.adev->dev), lookup.index,
                        lookup.pin_index, lookup.active_low);
        } else {
                dev_dbg(&adev->dev, "GPIO: looking up %d in _CRS\n", index);
                lookup.info.adev = adev;
        }

        ret = acpi_gpio_resource_lookup(&lookup, info);
        return ret ? ERR_PTR(ret) : lookup.desc;
}

struct gpio_desc *acpi_find_gpio(struct device *dev,
                                 const char *con_id,
                                 unsigned int idx,
                                 enum gpiod_flags *dflags,
                                 unsigned long *lookupflags)
{
        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) {
                        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))
                        break;
                if (PTR_ERR(desc) == -EPROBE_DEFER)
                        return ERR_CAST(desc);
        }

        /* Then from plain _CRS GPIOs */
        if (IS_ERR(desc)) {
                if (!acpi_can_fallback_to_crs(adev, con_id))
                        return ERR_PTR(-ENOENT);

                desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
                if (IS_ERR(desc))
                        return desc;
        }

        if (info.gpioint &&
            (*dflags == GPIOD_OUT_LOW || *dflags == GPIOD_OUT_HIGH)) {
                dev_dbg(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);
        return desc;
}

/**
 * acpi_node_get_gpiod() - get a GPIO descriptor from ACPI resources
 * @fwnode: pointer to an ACPI firmware node to get the GPIO information from
 * @propname: Property name of the GPIO
 * @index: index of GpioIo/GpioInt resource (starting from %0)
 * @info: info pointer to fill in (optional)
 *
 * If @fwnode is an ACPI device object, call acpi_get_gpiod_by_index() for it.
 * Otherwise (i.e. it is a data-only non-device object), use the property-based
 * GPIO lookup to get to the GPIO resource with the relevant information and use
 * that to obtain the GPIO descriptor to return.
 *
 * If the GPIO cannot be translated or there is an error an ERR_PTR is
 * returned.
 */
struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
                                      const char *propname, int index,
                                      struct acpi_gpio_info *info)
{
        struct acpi_gpio_lookup lookup;
        struct acpi_device *adev;
        int ret;

        adev = to_acpi_device_node(fwnode);
        if (adev)
                return acpi_get_gpiod_by_index(adev, propname, index, info);

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

        if (!propname)
                return ERR_PTR(-EINVAL);

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

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

        ret = acpi_gpio_resource_lookup(&lookup, info);
        return ret ? ERR_PTR(ret) : lookup.desc;
}

/**
 * acpi_dev_gpio_irq_get() - Find GpioInt and translate it to Linux IRQ number
 * @adev: pointer to a ACPI device to get IRQ from
 * @index: index of GpioInt resource (starting from %0)
 *
 * 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.
 *
 * Return: Linux IRQ number (> %0) on success, negative errno on failure.
 */
int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index)
{
        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;

                desc = acpi_get_gpiod_by_index(adev, NULL, i, &info);

                /* Ignore -EPROBE_DEFER, it only matters if idx matches */
                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;
                        char label[32];
                        int irq;

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

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

                        snprintf(label, sizeof(label), "GpioInt() %d", index);
                        ret = gpiod_configure_flags(desc, label, lflags, info.flags);
                        if (ret < 0)
                                return ret;

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

                        /* Set type if specified and different than the current one */
                        if (irq_flags != IRQ_TYPE_NONE &&
                            irq_flags != irq_get_trigger_type(irq))
                                irq_set_irq_type(irq, irq_flags);

                        return irq;
                }

        }
        return -ENOENT;
}
EXPORT_SYMBOL_GPL(acpi_dev_gpio_irq_get);

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;
        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, (u16)(pin_index + bits));
        for (i = pin_index; i < length; ++i) {
                int pin = agpio->pin_table[i];
                struct acpi_gpio_connection *conn;
                struct gpio_desc *desc;
                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) {
                        enum gpiod_flags flags = acpi_gpio_to_gpiod_flags(agpio);
                        const char *label = "ACPI:OpRegion";

                        desc = gpiochip_request_own_desc(chip, pin, label,
                                                         GPIO_ACTIVE_HIGH,
                                                         flags);
                        if (IS_ERR(desc)) {
                                status = AE_ERROR;
                                mutex_unlock(&achip->conn_lock);
                                goto out;
                        }

                        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->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 = 0;
        *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;
        struct fwnode_handle *fwnode;

        device_for_each_child_node(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");
                        fwnode_handle_put(fwnode);
                        return;
                }
        }
}

void acpi_gpiochip_add(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;

        acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
        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(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;
        }

        if (!chip->names)
                devprop_gpiochip_set_names(chip, dev_fwnode(chip->parent));

        acpi_gpiochip_request_regions(acpi_gpio);
        acpi_gpiochip_scan_gpios(acpi_gpio);
        acpi_walk_dep_device_list(handle);
}

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:
                        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 device / function
 * @dev:        GPIO consumer, can be %NULL for system-global GPIOs
 * @con_id:     function within the GPIO consumer
 *
 * Return:
 * The number of GPIOs associated with a device / function or %-ENOENT,
 * if no GPIO has been assigned to the requested function.
 */
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)
                        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;

                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;
}

bool acpi_can_fallback_to_crs(struct acpi_device *adev, const char *con_id)
{
        /* Never allow fallback if the device has properties */
        if (acpi_dev_has_props(adev) || adev->driver_gpios)
                return false;

        return con_id == NULL;
}

/* Run deferred acpi_gpiochip_request_irqs() */
static int acpi_gpio_handle_deferred_request_irqs(void)
{
        struct acpi_gpio_chip *acpi_gpio, *tmp;

        mutex_lock(&acpi_gpio_deferred_req_irqs_lock);
        list_for_each_entry_safe(acpi_gpio, tmp,
                                 &acpi_gpio_deferred_req_irqs_list,
                                 deferred_req_irqs_list_entry)
                acpi_gpiochip_request_irqs(acpi_gpio);

        acpi_gpio_deferred_req_irqs_done = true;
        mutex_unlock(&acpi_gpio_deferred_req_irqs_lock);

        return 0;
}
/* We must use _sync so that this runs after the first deferred_probe run */
late_initcall_sync(acpi_gpio_handle_deferred_request_irqs);

static const struct dmi_system_id run_edge_events_on_boot_blacklist[] = {
        {
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "MINIX"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Z83-4"),
                }
        },
        {} /* Terminating entry */
};

static int acpi_gpio_setup_params(void)
{
        if (run_edge_events_on_boot < 0) {
                if (dmi_check_system(run_edge_events_on_boot_blacklist))
                        run_edge_events_on_boot = 0;
                else
                        run_edge_events_on_boot = 1;
        }

        return 0;
}

/* Directly after dmi_setup() which runs as core_initcall() */
postcore_initcall(acpi_gpio_setup_params);