1 files changed, 84 insertions, 0 deletions

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index c0929d938ced..c4919966453d 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -712,3 +712,87 @@ void acpi_gpiochip_remove(struct gpio_chip *chip)
         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;
+}