// 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;
}