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path: root/drivers/gpio/gpiolib-acpi.c
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-rw-r--r--drivers/gpio/gpiolib-acpi.c808
1 files changed, 808 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
new file mode 100644
index 000000000..725d16138
--- /dev/null
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -0,0 +1,808 @@
+/*
+ * ACPI helpers for GPIO API
+ *
+ * Copyright (C) 2012, Intel Corporation
+ * Authors: Mathias Nyman <mathias.nyman@linux.intel.com>
+ * Mika Westerberg <mika.westerberg@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/errno.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/export.h>
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/pinctrl/pinctrl.h>
+
+#include "gpiolib.h"
+
+struct acpi_gpio_event {
+ struct list_head node;
+ acpi_handle handle;
+ unsigned int pin;
+ unsigned int irq;
+ struct gpio_desc *desc;
+};
+
+struct acpi_gpio_connection {
+ struct list_head node;
+ unsigned int pin;
+ struct gpio_desc *desc;
+};
+
+struct acpi_gpio_chip {
+ /*
+ * ACPICA requires that the first field of the context parameter
+ * passed to acpi_install_address_space_handler() is large enough
+ * to hold struct acpi_connection_info.
+ */
+ struct acpi_connection_info conn_info;
+ struct list_head conns;
+ struct mutex conn_lock;
+ struct gpio_chip *chip;
+ struct list_head events;
+};
+
+static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
+{
+ if (!gc->dev)
+ return false;
+
+ return ACPI_HANDLE(gc->dev) == data;
+}
+
+#ifdef CONFIG_PINCTRL
+/**
+ * acpi_gpiochip_pin_to_gpio_offset() - translates ACPI GPIO to Linux GPIO
+ * @chip: GPIO chip
+ * @pin: ACPI GPIO pin number from GpioIo/GpioInt resource
+ *
+ * Function takes ACPI GpioIo/GpioInt pin number as a parameter and
+ * translates it to a corresponding offset suitable to be passed to a
+ * GPIO controller driver.
+ *
+ * Typically the returned offset is same as @pin, but if the GPIO
+ * controller uses pin controller and the mapping is not contigous the
+ * offset might be different.
+ */
+static int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip, int pin)
+{
+ struct gpio_pin_range *pin_range;
+
+ /* If there are no ranges in this chip, use 1:1 mapping */
+ if (list_empty(&chip->pin_ranges))
+ return pin;
+
+ list_for_each_entry(pin_range, &chip->pin_ranges, node) {
+ const struct pinctrl_gpio_range *range = &pin_range->range;
+ int i;
+
+ if (range->pins) {
+ for (i = 0; i < range->npins; i++) {
+ if (range->pins[i] == pin)
+ return range->base + i - chip->base;
+ }
+ } else {
+ if (pin >= range->pin_base &&
+ pin < range->pin_base + range->npins) {
+ unsigned gpio_base;
+
+ gpio_base = range->base - chip->base;
+ return gpio_base + pin - range->pin_base;
+ }
+ }
+ }
+
+ return -EINVAL;
+}
+#else
+static inline int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip,
+ int pin)
+{
+ return pin;
+}
+#endif
+
+/**
+ * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
+ * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
+ * @pin: ACPI GPIO pin number (0-based, controller-relative)
+ *
+ * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
+ * error value
+ */
+
+static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
+{
+ struct gpio_chip *chip;
+ acpi_handle handle;
+ acpi_status status;
+ int offset;
+
+ status = acpi_get_handle(NULL, path, &handle);
+ if (ACPI_FAILURE(status))
+ return ERR_PTR(-ENODEV);
+
+ chip = gpiochip_find(handle, acpi_gpiochip_find);
+ if (!chip)
+ return ERR_PTR(-ENODEV);
+
+ offset = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
+ if (offset < 0)
+ return ERR_PTR(offset);
+
+ return gpiochip_get_desc(chip, offset);
+}
+
+static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
+{
+ struct acpi_gpio_event *event = data;
+
+ acpi_evaluate_object(event->handle, NULL, NULL, NULL);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
+{
+ struct acpi_gpio_event *event = data;
+
+ acpi_execute_simple_method(event->handle, NULL, event->pin);
+
+ return IRQ_HANDLED;
+}
+
+static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
+{
+ /* The address of this function is used as a key. */
+}
+
+static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
+ void *context)
+{
+ struct acpi_gpio_chip *acpi_gpio = context;
+ struct gpio_chip *chip = acpi_gpio->chip;
+ struct acpi_resource_gpio *agpio;
+ acpi_handle handle, evt_handle;
+ struct acpi_gpio_event *event;
+ irq_handler_t handler = NULL;
+ struct gpio_desc *desc;
+ unsigned long irqflags;
+ int ret, pin, irq;
+
+ if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
+ return AE_OK;
+
+ agpio = &ares->data.gpio;
+ if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT)
+ return AE_OK;
+
+ handle = ACPI_HANDLE(chip->dev);
+ pin = agpio->pin_table[0];
+
+ if (pin <= 255) {
+ char ev_name[5];
+ sprintf(ev_name, "_%c%02X",
+ agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
+ pin);
+ if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
+ handler = acpi_gpio_irq_handler;
+ }
+ if (!handler) {
+ if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
+ handler = acpi_gpio_irq_handler_evt;
+ }
+ if (!handler)
+ return AE_BAD_PARAMETER;
+
+ pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
+ if (pin < 0)
+ return AE_BAD_PARAMETER;
+
+ desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
+ if (IS_ERR(desc)) {
+ dev_err(chip->dev, "Failed to request GPIO\n");
+ return AE_ERROR;
+ }
+
+ gpiod_direction_input(desc);
+
+ ret = gpiochip_lock_as_irq(chip, pin);
+ if (ret) {
+ dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
+ goto fail_free_desc;
+ }
+
+ irq = gpiod_to_irq(desc);
+ if (irq < 0) {
+ dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
+ goto fail_unlock_irq;
+ }
+
+ irqflags = IRQF_ONESHOT;
+ if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
+ if (agpio->polarity == ACPI_ACTIVE_HIGH)
+ irqflags |= IRQF_TRIGGER_HIGH;
+ else
+ irqflags |= IRQF_TRIGGER_LOW;
+ } else {
+ switch (agpio->polarity) {
+ case ACPI_ACTIVE_HIGH:
+ irqflags |= IRQF_TRIGGER_RISING;
+ break;
+ case ACPI_ACTIVE_LOW:
+ irqflags |= IRQF_TRIGGER_FALLING;
+ break;
+ default:
+ irqflags |= IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING;
+ break;
+ }
+ }
+
+ event = kzalloc(sizeof(*event), GFP_KERNEL);
+ if (!event)
+ goto fail_unlock_irq;
+
+ event->handle = evt_handle;
+ event->irq = irq;
+ event->pin = pin;
+ event->desc = desc;
+
+ ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
+ "ACPI:Event", event);
+ if (ret) {
+ dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
+ event->irq);
+ goto fail_free_event;
+ }
+
+ list_add_tail(&event->node, &acpi_gpio->events);
+ return AE_OK;
+
+fail_free_event:
+ kfree(event);
+fail_unlock_irq:
+ gpiochip_unlock_as_irq(chip, pin);
+fail_free_desc:
+ gpiochip_free_own_desc(desc);
+
+ return AE_ERROR;
+}
+
+/**
+ * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
+ * @chip: GPIO chip
+ *
+ * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
+ * handled by ACPI event methods which need to be called from the GPIO
+ * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
+ * gpio pins have acpi event methods and assigns interrupt handlers that calls
+ * the acpi event methods for those pins.
+ */
+void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
+{
+ struct acpi_gpio_chip *acpi_gpio;
+ acpi_handle handle;
+ acpi_status status;
+
+ if (!chip->dev || !chip->to_irq)
+ return;
+
+ handle = ACPI_HANDLE(chip->dev);
+ if (!handle)
+ return;
+
+ status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
+ if (ACPI_FAILURE(status))
+ return;
+
+ INIT_LIST_HEAD(&acpi_gpio->events);
+ acpi_walk_resources(handle, "_AEI",
+ acpi_gpiochip_request_interrupt, acpi_gpio);
+}
+
+/**
+ * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts.
+ * @chip: GPIO chip
+ *
+ * Free interrupts associated with GPIO ACPI event method for the given
+ * GPIO chip.
+ */
+void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
+{
+ struct acpi_gpio_chip *acpi_gpio;
+ struct acpi_gpio_event *event, *ep;
+ acpi_handle handle;
+ acpi_status status;
+
+ if (!chip->dev || !chip->to_irq)
+ return;
+
+ handle = ACPI_HANDLE(chip->dev);
+ if (!handle)
+ return;
+
+ status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
+ if (ACPI_FAILURE(status))
+ return;
+
+ list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
+ struct gpio_desc *desc;
+
+ free_irq(event->irq, event);
+ desc = event->desc;
+ if (WARN_ON(IS_ERR(desc)))
+ continue;
+ gpiochip_unlock_as_irq(chip, event->pin);
+ gpiochip_free_own_desc(desc);
+ list_del(&event->node);
+ kfree(event);
+ }
+}
+
+int acpi_dev_add_driver_gpios(struct acpi_device *adev,
+ const struct acpi_gpio_mapping *gpios)
+{
+ if (adev && gpios) {
+ adev->driver_gpios = gpios;
+ return 0;
+ }
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(acpi_dev_add_driver_gpios);
+
+static bool acpi_get_driver_gpio_data(struct acpi_device *adev,
+ const char *name, int index,
+ struct acpi_reference_args *args)
+{
+ const struct acpi_gpio_mapping *gm;
+
+ if (!adev->driver_gpios)
+ return false;
+
+ for (gm = adev->driver_gpios; gm->name; gm++)
+ if (!strcmp(name, gm->name) && gm->data && index < gm->size) {
+ const struct acpi_gpio_params *par = gm->data + index;
+
+ args->adev = adev;
+ args->args[0] = par->crs_entry_index;
+ args->args[1] = par->line_index;
+ args->args[2] = par->active_low;
+ args->nargs = 3;
+ return true;
+ }
+
+ return false;
+}
+
+struct acpi_gpio_lookup {
+ struct acpi_gpio_info info;
+ int index;
+ int pin_index;
+ struct gpio_desc *desc;
+ int n;
+};
+
+static int acpi_find_gpio(struct acpi_resource *ares, void *data)
+{
+ struct acpi_gpio_lookup *lookup = data;
+
+ if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
+ return 1;
+
+ if (lookup->n++ == lookup->index && !lookup->desc) {
+ const struct acpi_resource_gpio *agpio = &ares->data.gpio;
+ int pin_index = lookup->pin_index;
+
+ if (pin_index >= agpio->pin_table_length)
+ return 1;
+
+ lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
+ agpio->pin_table[pin_index]);
+ lookup->info.gpioint =
+ agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
+
+ /*
+ * ActiveLow is only specified for GpioInt resource. If
+ * GpioIo is used then the only way to set the flag is
+ * to use _DSD "gpios" property.
+ */
+ if (lookup->info.gpioint)
+ lookup->info.active_low =
+ agpio->polarity == ACPI_ACTIVE_LOW;
+ }
+
+ return 1;
+}
+
+/**
+ * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
+ * @adev: pointer to a ACPI device to get GPIO from
+ * @propname: Property name of the GPIO (optional)
+ * @index: index of GpioIo/GpioInt resource (starting from %0)
+ * @info: info pointer to fill in (optional)
+ *
+ * Function goes through ACPI resources for @adev and based on @index looks
+ * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
+ * and returns it. @index matches GpioIo/GpioInt resources only so if there
+ * are total %3 GPIO resources, the index goes from %0 to %2.
+ *
+ * If @propname is specified the GPIO is looked using device property. In
+ * that case @index is used to select the GPIO entry in the property value
+ * (in case of multiple).
+ *
+ * If the GPIO cannot be translated or there is an error an ERR_PTR is
+ * returned.
+ *
+ * Note: if the GPIO resource has multiple entries in the pin list, this
+ * function only returns the first.
+ */
+struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
+ const char *propname, int index,
+ struct acpi_gpio_info *info)
+{
+ struct acpi_gpio_lookup lookup;
+ struct list_head resource_list;
+ bool active_low = false;
+ int ret;
+
+ if (!adev)
+ return ERR_PTR(-ENODEV);
+
+ memset(&lookup, 0, sizeof(lookup));
+ lookup.index = index;
+
+ if (propname) {
+ struct acpi_reference_args args;
+
+ dev_dbg(&adev->dev, "GPIO: looking up %s\n", propname);
+
+ memset(&args, 0, sizeof(args));
+ ret = acpi_dev_get_property_reference(adev, propname,
+ index, &args);
+ if (ret) {
+ bool found = acpi_get_driver_gpio_data(adev, propname,
+ index, &args);
+ if (!found)
+ return ERR_PTR(ret);
+ }
+
+ /*
+ * The property was found and resolved so need to
+ * lookup the GPIO based on returned args instead.
+ */
+ adev = args.adev;
+ if (args.nargs >= 2) {
+ lookup.index = args.args[0];
+ lookup.pin_index = args.args[1];
+ /*
+ * 3rd argument, if present is used to
+ * specify active_low.
+ */
+ if (args.nargs >= 3)
+ active_low = !!args.args[2];
+ }
+
+ dev_dbg(&adev->dev, "GPIO: _DSD returned %s %zd %llu %llu %llu\n",
+ dev_name(&adev->dev), args.nargs,
+ args.args[0], args.args[1], args.args[2]);
+ } else {
+ dev_dbg(&adev->dev, "GPIO: looking up %d in _CRS\n", index);
+ }
+
+ INIT_LIST_HEAD(&resource_list);
+ ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
+ &lookup);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ acpi_dev_free_resource_list(&resource_list);
+
+ if (lookup.desc && info) {
+ *info = lookup.info;
+ if (active_low)
+ info->active_low = active_low;
+ }
+
+ return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
+}
+
+static acpi_status
+acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
+ u32 bits, u64 *value, void *handler_context,
+ void *region_context)
+{
+ struct acpi_gpio_chip *achip = region_context;
+ struct gpio_chip *chip = achip->chip;
+ struct acpi_resource_gpio *agpio;
+ struct acpi_resource *ares;
+ int pin_index = (int)address;
+ acpi_status status;
+ bool pull_up;
+ int length;
+ int i;
+
+ status = acpi_buffer_to_resource(achip->conn_info.connection,
+ achip->conn_info.length, &ares);
+ if (ACPI_FAILURE(status))
+ return status;
+
+ if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) {
+ ACPI_FREE(ares);
+ return AE_BAD_PARAMETER;
+ }
+
+ agpio = &ares->data.gpio;
+ pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;
+
+ if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT &&
+ function == ACPI_WRITE)) {
+ ACPI_FREE(ares);
+ return AE_BAD_PARAMETER;
+ }
+
+ length = min(agpio->pin_table_length, (u16)(pin_index + bits));
+ for (i = pin_index; i < length; ++i) {
+ int pin = agpio->pin_table[i];
+ struct acpi_gpio_connection *conn;
+ struct gpio_desc *desc;
+ bool found;
+
+ pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
+ if (pin < 0) {
+ status = AE_BAD_PARAMETER;
+ goto out;
+ }
+
+ mutex_lock(&achip->conn_lock);
+
+ found = false;
+ list_for_each_entry(conn, &achip->conns, node) {
+ if (conn->pin == pin) {
+ found = true;
+ desc = conn->desc;
+ break;
+ }
+ }
+ if (!found) {
+ desc = gpiochip_request_own_desc(chip, pin,
+ "ACPI:OpRegion");
+ if (IS_ERR(desc)) {
+ status = AE_ERROR;
+ mutex_unlock(&achip->conn_lock);
+ goto out;
+ }
+
+ switch (agpio->io_restriction) {
+ case ACPI_IO_RESTRICT_INPUT:
+ gpiod_direction_input(desc);
+ break;
+ case ACPI_IO_RESTRICT_OUTPUT:
+ /*
+ * ACPI GPIO resources don't contain an
+ * initial value for the GPIO. Therefore we
+ * deduce that value from the pull field
+ * instead. If the pin is pulled up we
+ * assume default to be high, otherwise
+ * low.
+ */
+ gpiod_direction_output(desc, pull_up);
+ break;
+ default:
+ /*
+ * Assume that the BIOS has configured the
+ * direction and pull accordingly.
+ */
+ break;
+ }
+
+ conn = kzalloc(sizeof(*conn), GFP_KERNEL);
+ if (!conn) {
+ status = AE_NO_MEMORY;
+ gpiochip_free_own_desc(desc);
+ mutex_unlock(&achip->conn_lock);
+ goto out;
+ }
+
+ conn->pin = pin;
+ conn->desc = desc;
+ list_add_tail(&conn->node, &achip->conns);
+ }
+
+ mutex_unlock(&achip->conn_lock);
+
+ if (function == ACPI_WRITE)
+ gpiod_set_raw_value_cansleep(desc,
+ !!((1 << i) & *value));
+ else
+ *value |= (u64)gpiod_get_raw_value_cansleep(desc) << i;
+ }
+
+out:
+ ACPI_FREE(ares);
+ return status;
+}
+
+static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip)
+{
+ struct gpio_chip *chip = achip->chip;
+ acpi_handle handle = ACPI_HANDLE(chip->dev);
+ acpi_status status;
+
+ INIT_LIST_HEAD(&achip->conns);
+ mutex_init(&achip->conn_lock);
+ status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
+ acpi_gpio_adr_space_handler,
+ NULL, achip);
+ if (ACPI_FAILURE(status))
+ dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n");
+}
+
+static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
+{
+ struct gpio_chip *chip = achip->chip;
+ acpi_handle handle = ACPI_HANDLE(chip->dev);
+ struct acpi_gpio_connection *conn, *tmp;
+ acpi_status status;
+
+ status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
+ acpi_gpio_adr_space_handler);
+ if (ACPI_FAILURE(status)) {
+ dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n");
+ return;
+ }
+
+ list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) {
+ gpiochip_free_own_desc(conn->desc);
+ list_del(&conn->node);
+ kfree(conn);
+ }
+}
+
+void acpi_gpiochip_add(struct gpio_chip *chip)
+{
+ struct acpi_gpio_chip *acpi_gpio;
+ acpi_handle handle;
+ acpi_status status;
+
+ if (!chip || !chip->dev)
+ return;
+
+ handle = ACPI_HANDLE(chip->dev);
+ if (!handle)
+ return;
+
+ acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
+ if (!acpi_gpio) {
+ dev_err(chip->dev,
+ "Failed to allocate memory for ACPI GPIO chip\n");
+ return;
+ }
+
+ acpi_gpio->chip = chip;
+
+ status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio);
+ if (ACPI_FAILURE(status)) {
+ dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n");
+ kfree(acpi_gpio);
+ return;
+ }
+
+ acpi_gpiochip_request_regions(acpi_gpio);
+}
+
+void acpi_gpiochip_remove(struct gpio_chip *chip)
+{
+ struct acpi_gpio_chip *acpi_gpio;
+ acpi_handle handle;
+ acpi_status status;
+
+ if (!chip || !chip->dev)
+ return;
+
+ handle = ACPI_HANDLE(chip->dev);
+ if (!handle)
+ return;
+
+ status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
+ if (ACPI_FAILURE(status)) {
+ dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n");
+ return;
+ }
+
+ acpi_gpiochip_free_regions(acpi_gpio);
+
+ acpi_detach_data(handle, acpi_gpio_chip_dh);
+ kfree(acpi_gpio);
+}
+
+static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
+{
+ const union acpi_object *element = obj->package.elements;
+ const union acpi_object *end = element + obj->package.count;
+ unsigned int count = 0;
+
+ while (element < end) {
+ if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
+ count++;
+
+ element++;
+ }
+ return count;
+}
+
+static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
+{
+ unsigned int *count = data;
+
+ if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
+ *count += ares->data.gpio.pin_table_length;
+
+ return 1;
+}
+
+/**
+ * acpi_gpio_count - return the number of GPIOs associated with a
+ * device / function or -ENOENT if no GPIO has been
+ * assigned to the requested function.
+ * @dev: GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id: function within the GPIO consumer
+ */
+int acpi_gpio_count(struct device *dev, const char *con_id)
+{
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+ const union acpi_object *obj;
+ const struct acpi_gpio_mapping *gm;
+ int count = -ENOENT;
+ int ret;
+ char propname[32];
+ unsigned int i;
+
+ /* Try first from _DSD */
+ for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
+ if (con_id && strcmp(con_id, "gpios"))
+ snprintf(propname, sizeof(propname), "%s-%s",
+ con_id, gpio_suffixes[i]);
+ else
+ snprintf(propname, sizeof(propname), "%s",
+ gpio_suffixes[i]);
+
+ ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
+ &obj);
+ if (ret == 0) {
+ if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
+ count = 1;
+ else if (obj->type == ACPI_TYPE_PACKAGE)
+ count = acpi_gpio_package_count(obj);
+ } else if (adev->driver_gpios) {
+ for (gm = adev->driver_gpios; gm->name; gm++)
+ if (strcmp(propname, gm->name) == 0) {
+ count = gm->size;
+ break;
+ }
+ }
+ if (count >= 0)
+ break;
+ }
+
+ /* Then from plain _CRS GPIOs */
+ if (count < 0) {
+ struct list_head resource_list;
+ unsigned int crs_count = 0;
+
+ INIT_LIST_HEAD(&resource_list);
+ acpi_dev_get_resources(adev, &resource_list,
+ acpi_find_gpio_count, &crs_count);
+ acpi_dev_free_resource_list(&resource_list);
+ if (crs_count > 0)
+ count = crs_count;
+ }
+ return count;
+}