diff --git a/Documentation/wmi/devices/dell-wmi-ddv.rst b/Documentation/wmi/devices/dell-wmi-ddv.rst
new file mode 100644
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+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+============================================
+Dell DDV WMI interface driver (dell-wmi-ddv)
+============================================
+
+Introduction
+============
+
+Many Dell notebooks made after ~2020 support a WMI-based interface for
+retrieving various system data like battery temperature, ePPID, diagostic data
+and fan/thermal sensor data.
+
+This interface is likely used by the `Dell Data Vault` software on Windows,
+so it was called `DDV`. Currently the ``dell-wmi-ddv`` driver supports
+version 2 and 3 of the interface, with support for new interface versions
+easily added.
+
+.. warning:: The interface is regarded as internal by Dell, so no vendor
+             documentation is available. All knowledge was thus obtained by
+             trial-and-error, please keep that in mind.
+
+Dell ePPID (electronic Piece Part Identification)
+=================================================
+
+The Dell ePPID is used to uniquely identify components in Dell machines,
+including batteries. It has a form similar to `CC-PPPPPP-MMMMM-YMD-SSSS-FFF`
+and contains the following information:
+
+* Country code of origin (CC).
+* Part number with the first character being a filling number (PPPPPP).
+* Manufacture Identification (MMMMM).
+* Manufacturing Year/Month/Date (YMD) in base 36, with Y being the last digit
+  of the year.
+* Manufacture Sequence Number (SSSS).
+* Optional Firmware Version/Revision (FFF).
+
+The `eppidtool <https://pypi.org/project/eppidtool>`_ python utility can be used
+to decode and display this information.
+
+All information regarding the Dell ePPID was gathered using Dell support
+documentation and `this website <https://telcontar.net/KBK/Dell/date_codes>`_.
+
+WMI interface description
+=========================
+
+The WMI interface description can be decoded from the embedded binary MOF (bmof)
+data using the `bmfdec <https://github.com/pali/bmfdec>`_ utility:
+
+::
+
+ [WMI, Dynamic, Provider("WmiProv"), Locale("MS\\0x409"), Description("WMI Function"), guid("{8A42EA14-4F2A-FD45-6422-0087F7A7E608}")]
+ class DDVWmiMethodFunction {
+   [key, read] string InstanceName;
+   [read] boolean Active;
+
+   [WmiMethodId(1), Implemented, read, write, Description("Return Battery Design Capacity.")] void BatteryDesignCapacity([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(2), Implemented, read, write, Description("Return Battery Full Charge Capacity.")] void BatteryFullChargeCapacity([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(3), Implemented, read, write, Description("Return Battery Manufacture Name.")] void BatteryManufactureName([in] uint32 arg2, [out] string argr);
+   [WmiMethodId(4), Implemented, read, write, Description("Return Battery Manufacture Date.")] void BatteryManufactureDate([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(5), Implemented, read, write, Description("Return Battery Serial Number.")] void BatterySerialNumber([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(6), Implemented, read, write, Description("Return Battery Chemistry Value.")] void BatteryChemistryValue([in] uint32 arg2, [out] string argr);
+   [WmiMethodId(7), Implemented, read, write, Description("Return Battery Temperature.")] void BatteryTemperature([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(8), Implemented, read, write, Description("Return Battery Current.")] void BatteryCurrent([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(9), Implemented, read, write, Description("Return Battery Voltage.")] void BatteryVoltage([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(10), Implemented, read, write, Description("Return Battery Manufacture Access(MA code).")] void BatteryManufactureAceess([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(11), Implemented, read, write, Description("Return Battery Relative State-Of-Charge.")] void BatteryRelativeStateOfCharge([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(12), Implemented, read, write, Description("Return Battery Cycle Count")] void BatteryCycleCount([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(13), Implemented, read, write, Description("Return Battery ePPID")] void BatteryePPID([in] uint32 arg2, [out] string argr);
+   [WmiMethodId(14), Implemented, read, write, Description("Return Battery Raw Analytics Start")] void BatteryeRawAnalyticsStart([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(15), Implemented, read, write, Description("Return Battery Raw Analytics")] void BatteryeRawAnalytics([in] uint32 arg2, [out] uint32 RawSize, [out, WmiSizeIs("RawSize") : ToInstance] uint8 RawData[]);
+   [WmiMethodId(16), Implemented, read, write, Description("Return Battery Design Voltage.")] void BatteryDesignVoltage([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(17), Implemented, read, write, Description("Return Battery Raw Analytics A Block")] void BatteryeRawAnalyticsABlock([in] uint32 arg2, [out] uint32 RawSize, [out, WmiSizeIs("RawSize") : ToInstance] uint8 RawData[]);
+   [WmiMethodId(18), Implemented, read, write, Description("Return Version.")] void ReturnVersion([in] uint32 arg2, [out] uint32 argr);
+   [WmiMethodId(32), Implemented, read, write, Description("Return Fan Sensor Information")] void FanSensorInformation([in] uint32 arg2, [out] uint32 RawSize, [out, WmiSizeIs("RawSize") : ToInstance] uint8 RawData[]);
+   [WmiMethodId(34), Implemented, read, write, Description("Return Thermal Sensor Information")] void ThermalSensorInformation([in] uint32 arg2, [out] uint32 RawSize, [out, WmiSizeIs("RawSize") : ToInstance] uint8 RawData[]);
+ };
+
+Each WMI method takes an ACPI buffer containing a 32-bit index as input argument,
+with the first 8 bit being used to specify the battery when using battery-related
+WMI methods. Other WMI methods may ignore this argument or interpret it
+differently. The WMI method output format varies:
+
+* if the function has only a single output, then an ACPI object
+  of the corresponding type is returned
+* if the function has multiple outputs, when an ACPI package
+  containing the outputs in the same order is returned
+
+The format of the output should be thoroughly checked, since many methods can
+return malformed data in case of an error.
+
+The data format of many battery-related methods seems to be based on the
+`Smart Battery Data Specification`, so unknown battery-related methods are
+likely to follow this standard in some way.
+
+WMI method GetBatteryDesignCapacity()
+-------------------------------------
+
+Returns the design capacity of the battery in mAh as an u16.
+
+WMI method BatteryFullCharge()
+------------------------------
+
+Returns the full charge capacity of the battery in mAh as an u16.
+
+WMI method BatteryManufactureName()
+-----------------------------------
+
+Returns the manufacture name of the battery as an ASCII string.
+
+WMI method BatteryManufactureDate()
+-----------------------------------
+
+Returns the manufacture date of the battery as an u16.
+The date is encoded in the following manner:
+
+- bits 0 to 4 contain the manufacture day.
+- bits 5 to 8 contain the manufacture month.
+- bits 9 to 15 contain the manufacture year biased by 1980.
+
+.. note::
+   The data format needs to be verified on more machines.
+
+WMI method BatterySerialNumber()
+--------------------------------
+
+Returns the serial number of the battery as an u16.
+
+WMI method BatteryChemistryValue()
+----------------------------------
+
+Returns the chemistry of the battery as an ASCII string.
+Known values are:
+
+- "Li-I" for Li-Ion
+
+WMI method BatteryTemperature()
+-------------------------------
+
+Returns the temperature of the battery in tenth degree kelvin as an u16.
+
+WMI method BatteryCurrent()
+---------------------------
+
+Returns the current flow of the battery in mA as an s16.
+Negative values indicate discharging.
+
+WMI method BatteryVoltage()
+---------------------------
+
+Returns the voltage flow of the battery in mV as an u16.
+
+WMI method BatteryManufactureAccess()
+-------------------------------------
+
+Returns a manufacture-defined value as an u16.
+
+WMI method BatteryRelativeStateOfCharge()
+-----------------------------------------
+
+Returns the capacity of the battery in percent as an u16.
+
+WMI method BatteryCycleCount()
+------------------------------
+
+Returns the cycle count of the battery as an u16.
+
+WMI method BatteryePPID()
+-------------------------
+
+Returns the ePPID of the battery as an ASCII string.
+
+WMI method BatteryeRawAnalyticsStart()
+--------------------------------------
+
+Performs an analysis of the battery and returns a status code:
+
+- ``0x0``: Success
+- ``0x1``: Interface not supported
+- ``0xfffffffe``: Error/Timeout
+
+.. note::
+   The meaning of this method is still largely unknown.
+
+WMI method BatteryeRawAnalytics()
+---------------------------------
+
+Returns a buffer usually containg 12 blocks of analytics data.
+Those blocks contain:
+- block number starting with 0 (u8)
+- 31 bytes of unknown data
+
+.. note::
+   The meaning of this method is still largely unknown.
+
+WMI method BatteryDesignVoltage()
+---------------------------------
+
+Returns the design voltage of the battery in mV as an u16.
+
+WMI method BatteryeRawAnalyticsABlock()
+---------------------------------------
+
+Returns a single block of analytics data, with the second byte
+of the index being used for selecting the block number.
+
+*Supported since WMI interface version 3!*
+
+.. note::
+   The meaning of this method is still largely unknown.
+
+WMI method ReturnVersion()
+--------------------------
+
+Returns the WMI interface version as an u32.
+
+WMI method FanSensorInformation()
+---------------------------------
+
+Returns a buffer containg fan sensor entries, terminated
+with a single ``0xff``.
+Those entries contain:
+
+- fan type (u8)
+- fan speed in RPM (little endian u16)
+
+WMI method ThermalSensorInformation()
+-------------------------------------
+
+Returns a buffer containing thermal sensor entries, terminated
+with a single ``0xff``.
+Those entries contain:
+
+- thermal type (u8)
+- current temperature (s8)
+- min. temperature (s8)
+- max. temperature (s8)
+- unknown field (u8)
+
+.. note::
+   TODO: Find out what the meaning of the last byte is.
+
+ACPI battery matching algorithm
+===============================
+
+The algorithm used to match ACPI batteries to indices is based on information
+which was found inside the logging messages of the OEM software.
+
+Basically for each new ACPI battery, the serial numbers of the batteries behind
+indices 1 till 3 are compared with the serial number of the ACPI battery.
+Since the serial number of the ACPI battery can either be encoded as a normal
+integer or as a hexadecimal value, both cases need to be checked. The first
+index with a matching serial number is then selected.
+
+A serial number of 0 indicates that the corresponding index is not associated
+with an actual battery, or that the associated battery is not present.
+
+Some machines like the Dell Inspiron 3505 only support a single battery and thus
+ignore the battery index. Because of this the driver depends on the ACPI battery
+hook mechanism to discover batteries.
+
+.. note::
+   The ACPI battery matching algorithm currently used inside the driver is
+   outdated and does not match the algorithm described above. The reasons for
+   this are differences in the handling of the ToHexString() ACPI opcode between
+   Linux and Windows, which distorts the serial number of ACPI batteries on many
+   machines. Until this issue is resolved, the driver cannot use the above
+   algorithm.
+
+Reverse-Engineering the DDV WMI interface
+=========================================
+
+1. Find a supported Dell notebook, usually made after ~2020.
+2. Dump the ACPI tables and search for the WMI device (usually called "ADDV").
+3. Decode the corresponding bmof data and look at the ASL code.
+4. Try to deduce the meaning of a certain WMI method by comparing the control
+   flow with other ACPI methods (_BIX or _BIF for battery related methods
+   for example).
+5. Use the built-in UEFI diagostics to view sensor types/values for fan/thermal
+   related methods (sometimes overwriting static ACPI data fields can be used
+   to test different sensor type values, since on some machines this data is
+   not reinitialized upon a warm reset).
+
+Alternatively:
+
+1. Load the ``dell-wmi-ddv`` driver, use the ``force`` module param
+   if necessary.
+2. Use the debugfs interface to access the raw fan/thermal sensor buffer data.
+3. Compare the data with the built-in UEFI diagnostics.
+
+In case the DDV WMI interface version available on your Dell notebook is not
+supported or you are seeing unknown fan/thermal sensors, please submit a
+bugreport on `bugzilla <https://bugzilla.kernel.org>`_ so they can be added
+to the ``dell-wmi-ddv`` driver.
+
+See Documentation/admin-guide/reporting-issues.rst for further information.
diff --git a/MAINTAINERS b/MAINTAINERS
index 4d5b1f6d77f6..66e4eabaf972 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5804,6 +5804,7 @@ M:	Armin Wolf <W_Armin@gmx.de>
 S:	Maintained
 F:	Documentation/ABI/testing/debugfs-dell-wmi-ddv
 F:	Documentation/ABI/testing/sysfs-platform-dell-wmi-ddv
+F:	Documentation/wmi/devices/dell-wmi-ddv.rst
 F:	drivers/platform/x86/dell/dell-wmi-ddv.c

 DELL WMI SYSMAN DRIVER
