3 files changed, 125 insertions, 1 deletions

diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index 94a656131885..b0d541042ac6 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -199,6 +199,8 @@ the device to the driver. For example:
         {
                 Name (SBUF, ResourceTemplate()
                 {
+                        ...
+                        // Used to power on/off the device
                         GpioIo (Exclusive, PullDefault, 0x0000, 0x0000,
                                 IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0",
                                 0x00, ResourceConsumer,,)
@@ -206,10 +208,20 @@ the device to the driver. For example:
                                 // Pin List
                                 0x0055
                         }
+
+                        // Interrupt for the device
+                        GpioInt (Edge, ActiveHigh, ExclusiveAndWake, PullNone,
+                                 0x0000, "\\_SB.PCI0.GPI0", 0x00, ResourceConsumer,,)
+                        {
+                                // Pin list
+                                0x0058
+                        }
+
                         ...
 
-                        Return (SBUF)
                 }
+
+                Return (SBUF)
         }
 
 These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0"
@@ -220,6 +232,24 @@ The driver can do this by including <linux/acpi_gpio.h> and then calling
 acpi_get_gpio(path, gpio). This will return the Linux GPIO number or
 negative errno if there was no translation found.
 
+In a simple case of just getting the Linux GPIO number from device
+resources one can use acpi_get_gpio_by_index() helper function. It takes
+pointer to the device and index of the GpioIo/GpioInt descriptor in the
+device resources list. For example:
+
+        int gpio_irq, gpio_power;
+        int ret;
+
+        gpio_irq = acpi_get_gpio_by_index(dev, 1, NULL);
+        if (gpio_irq < 0)
+                /* handle error */
+
+        gpio_power = acpi_get_gpio_by_index(dev, 0, NULL);
+        if (gpio_power < 0)
+                /* handle error */
+
+        /* Now we can use the GPIO numbers */
+
 Other GpioIo parameters must be converted first by the driver to be
 suitable to the gpiolib before passing them.
 
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 89336c4f82cd..5c1ef2b3ef18 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -201,6 +201,83 @@ void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
 }
 EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
 
+struct acpi_gpio_lookup {
+        struct acpi_gpio_info info;
+        int index;
+        int gpio;
+        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->gpio < 0) {
+                const struct acpi_resource_gpio *agpio = &ares->data.gpio;
+
+                lookup->gpio = acpi_get_gpio(agpio->resource_source.string_ptr,
+                                             agpio->pin_table[0]);
+                lookup->info.gpioint =
+                        agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
+        }
+
+        return 1;
+}
+
+/**
+ * acpi_get_gpio_by_index() - get a GPIO number from device resources
+ * @dev: pointer to a device to get GPIO from
+ * @index: index of GpioIo/GpioInt resource (starting from %0)
+ * @info: info pointer to fill in (optional)
+ *
+ * Function goes through ACPI resources for @dev and based on @index looks
+ * up a GpioIo/GpioInt resource, translates it to the Linux GPIO number,
+ * 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 the GPIO cannot be translated or there is an error, negative errno is
+ * returned.
+ *
+ * Note: if the GPIO resource has multiple entries in the pin list, this
+ * function only returns the first.
+ */
+int acpi_get_gpio_by_index(struct device *dev, int index,
+                           struct acpi_gpio_info *info)
+{
+        struct acpi_gpio_lookup lookup;
+        struct list_head resource_list;
+        struct acpi_device *adev;
+        acpi_handle handle;
+        int ret;
+
+        if (!dev)
+                return -EINVAL;
+
+        handle = ACPI_HANDLE(dev);
+        if (!handle || acpi_bus_get_device(handle, &adev))
+                return -ENODEV;
+
+        memset(&lookup, 0, sizeof(lookup));
+        lookup.index = index;
+        lookup.gpio = -ENODEV;
+
+        INIT_LIST_HEAD(&resource_list);
+        ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
+                                     &lookup);
+        if (ret < 0)
+                return ret;
+
+        acpi_dev_free_resource_list(&resource_list);
+
+        if (lookup.gpio >= 0 && info)
+                *info = lookup.info;
+
+        return lookup.gpio;
+}
+EXPORT_SYMBOL_GPL(acpi_get_gpio_by_index);
 
 /**
  * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
diff --git a/include/linux/acpi_gpio.h b/include/linux/acpi_gpio.h
index 213135f44333..4c120a1e0ca3 100644
--- a/include/linux/acpi_gpio.h
+++ b/include/linux/acpi_gpio.h
@@ -1,12 +1,23 @@
 #ifndef _LINUX_ACPI_GPIO_H_
 #define _LINUX_ACPI_GPIO_H_
 
+#include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/gpio.h>
 
+/**
+ * struct acpi_gpio_info - ACPI GPIO specific information
+ * @gpioint: if %true this GPIO is of type GpioInt otherwise type is GpioIo
+ */
+struct acpi_gpio_info {
+        bool gpioint;
+};
+
 #ifdef CONFIG_GPIO_ACPI
 
 int acpi_get_gpio(char *path, int pin);
+int acpi_get_gpio_by_index(struct device *dev, int index,
+                           struct acpi_gpio_info *info);
 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip);
 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip);
 
@@ -17,6 +28,12 @@ static inline int acpi_get_gpio(char *path, int pin)
         return -ENODEV;
 }
 
+static inline int acpi_get_gpio_by_index(struct device *dev, int index,
+                                         struct acpi_gpio_info *info)
+{
+        return -ENODEV;
+}
+
 static inline void acpi_gpiochip_request_interrupts(struct gpio_chip *chip) { }
 static inline void acpi_gpiochip_free_interrupts(struct gpio_chip *chip) { }