diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
index ff9aa1afdc62..1e16a40da3ba 100644
--- a/Documentation/driver-api/index.rst
+++ b/Documentation/driver-api/index.rst
@@ -113,6 +113,7 @@ available subsections can be seen below.
    xillybus
    zorro
    hte/index
+   wmi

 .. only::  subproject and html

diff --git a/Documentation/driver-api/wmi.rst b/Documentation/driver-api/wmi.rst
new file mode 100644
index 000000000000..6ca58c8249e5
--- /dev/null
+++ b/Documentation/driver-api/wmi.rst
@@ -0,0 +1,21 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+==============
+WMI Driver API
+==============
+
+The WMI driver core supports a more modern bus-based interface for interacting
+with WMI devices, and an older GUID-based interface. The latter interface is
+considered to be deprecated, so new WMI drivers should generally avoid it since
+it has some issues with multiple WMI devices and events sharing the same GUIDs
+and/or notification IDs. The modern bus-based interface instead maps each
+WMI device to a :c:type:`struct wmi_device <wmi_device>`, so it supports
+WMI devices sharing GUIDs and/or notification IDs. Drivers can then register
+a :c:type:`struct wmi_driver <wmi_driver>`, which will be bound to compatible
+WMI devices by the driver core.
+
+.. kernel-doc:: include/linux/wmi.h
+   :internal:
+
+.. kernel-doc:: drivers/platform/x86/wmi.c
+   :export:
diff --git a/Documentation/subsystem-apis.rst b/Documentation/subsystem-apis.rst
index b51f38527e14..69f5e4d53bad 100644
--- a/Documentation/subsystem-apis.rst
+++ b/Documentation/subsystem-apis.rst
@@ -57,3 +57,4 @@ needed).
    scheduler/index
    mhi/index
    peci/index
+   wmi/index
diff --git a/Documentation/wmi/acpi-interface.rst b/Documentation/wmi/acpi-interface.rst
new file mode 100644
index 000000000000..d31af0ed9c08
--- /dev/null
+++ b/Documentation/wmi/acpi-interface.rst
@@ -0,0 +1,96 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+==================
+ACPI WMI interface
+==================
+
+The ACPI WMI interface is a proprietary extension of the ACPI specification made
+by Microsoft to allow hardware vendors to embed WMI (Windows Management Instrumentation)
+objects inside their ACPI firmware. Typical functions implemented over ACPI WMI
+are hotkey events on modern notebooks and configuration of BIOS options.
+
+PNP0C14 ACPI device
+-------------------
+
+Discovery of WMI objects is handled by defining ACPI devices with a PNP ID
+of ``PNP0C14``. These devices will contain a set of ACPI buffers and methods
+used for mapping and execution of WMI methods and/or queries. If there exist
+multiple of such devices, then each device is required to have a
+unique ACPI UID.
+
+_WDG buffer
+-----------
+
+The ``_WDG`` buffer is used to discover WMI objects and is required to be
+static. Its internal structure consists of data blocks with a size of 20 bytes,
+containing the following data:
+
+======= =============== =====================================================
+Offset  Size (in bytes) Content
+======= =============== =====================================================
+0x00    16              128 bit Variant 2 object GUID.
+0x10    2               2 character method ID or single byte notification ID.
+0x12    1               Object instance count.
+0x13    1               Object flags.
+======= =============== =====================================================
+
+The WMI object flags control whether the method or notification ID is used:
+
+- 0x1: Data block usage is expensive and must be explicitly enabled/disabled.
+- 0x2: Data block contains WMI methods.
+- 0x4: Data block contains ASCIZ string.
+- 0x8: Data block describes a WMI event, use notification ID instead
+  of method ID.
+
+Each WMI object GUID can appear multiple times inside a system.
+The method/notification ID is used to construct the ACPI method names used for
+interacting with the WMI object.
+
+WQxx ACPI methods
+-----------------
+
+If a data block does not contain WMI methods, then its content can be retrieved
+by this required ACPI method. The last two characters of the ACPI method name
+are the method ID of the data block to query. Their single parameter is an
+integer describing the instance which should be queried. This parameter can be
+omitted if the data block contains only a single instance.
+
+WSxx ACPI methods
+-----------------
+
+Similar to the ``WQxx`` ACPI methods, except that it is optional and takes an
+additional buffer as its second argument. The instance argument also cannot
+be omitted.
+
+WMxx ACPI methods
+-----------------
+
+Used for executing WMI methods associated with a data block. The last two
+characters of the ACPI method name are the method ID of the data block
+containing the WMI methods. Their first parameter is a integer describing the
+instance which methods should be executed. The second parameter is an integer
+describing the WMI method ID to execute, and the third parameter is a buffer
+containing the WMI method parameters. If the data block is marked as containing
+an ASCIZ string, then this buffer should contain an ASCIZ string. The ACPI
+method will return the result of the executed WMI method.
+
+WExx ACPI methods
+-----------------
+
+Used for optionally enabling/disabling WMI events, the last two characters of
+the ACPI method are the notification ID of the data block describing the WMI
+event as hexadecimal value. Their first parameter is an integer with a value
+of 0 if the WMI event should be disabled, other values will enable
+the WMI event.
+
+WCxx ACPI methods
+-----------------
+Similar to the ``WExx`` ACPI methods, except that it controls data collection
+instead of events and thus the last two characters of the ACPI method name are
+the method ID of the data block to enable/disable.
+
+_WED ACPI method
+----------------
+
+Used to retrieve additional WMI event data, its single parameter is a integer
+holding the notification ID of the event.
diff --git a/Documentation/wmi/index.rst b/Documentation/wmi/index.rst
new file mode 100644
index 000000000000..b29933a86380
--- /dev/null
+++ b/Documentation/wmi/index.rst
@@ -0,0 +1,18 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+=============
+WMI Subsystem
+=============
+
+.. toctree::
+   :maxdepth: 1
+
+   acpi-interface
+
+.. only::  subproject and html
+
+
+   Indices
+   =======
+
+   * :ref:`genindex`
diff --git a/MAINTAINERS b/MAINTAINERS
index 0c9011f5fc17..979d37176429 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -449,6 +449,8 @@ F:	include/linux/acpi_viot.h
 ACPI WMI DRIVER
 L:	platform-driver-x86@vger.kernel.org
 S:	Orphan
+F:	Documentation/driver-api/wmi.rst
+F:	Documentation/wmi/
 F:	drivers/platform/x86/wmi.c
 F:	include/uapi/linux/wmi.h

