Documentation/wmi/driver-development-guide.rst

1 .. SPDX-License-Identifier: GPL-2.0-or-later
8 documented at Documentation/driver-api/wmi.rst. This document will serve
11 using the deprecated GUID-based WMI interface.
14 --------------------------------
22   lswmi -V
30 The ``wmi-bmof`` driver exposes this information to userspace, see
31 Documentation/wmi/devices/wmi-bmof.rst.
37   ./bmf2mof /sys/bus/wmi/devices/05901221-D566-11D1-B2F0-00A0C9062910[-X]/bmof
39 Sometimes, looking at the disassembled ACPI tables used to describe the WMI device
40 helps in understanding how the WMI device is supposed to work. The path of the ACPI
49 --------------------------
57          { "936DA01F-9ABD-4D9D-80C7-02AF85C822A8", NULL },
79 driver-specific data structures and initialising interfaces to other kernel subsystems should
85 Documentation/driver-api/driver-model/devres.rst for details.
88 the WMI device and put it in a well-known state for the WMI driver to pick up later after reboot
92 and are forbidden from using any deprecated GUID-based WMI functions. This means that the
97 Documentation/driver-api/driver-model/design-patterns.rst.
99 .. warning:: Using both GUID-based and non-GUID-based functions for querying WMI data blocks and
104 ------------------
107 structure of the ACPI buffer passed to this function is device-specific and usually
108 needs some tinkering to get right. Looking at the ACPI tables containing the WMI
110 are also device-specific, looking at the decoded Binary MOF is usually enough to
118 ----------------------
121 structure of the returned ACPI object is again device-specific. Some WMI devices
126 Take a look at drivers/platform/x86/intel/wmi/sbl-fw-update.c for an example
130 -----------------
134 the structure of the ACPI object passed to this callback is device-specific, and freeing the
135 ACPI object is being done by the WMI subsystem, not the driver.
147 Take a look at drivers/platform/x86/xiaomi-wmi.c for an example WMI event driver.
150 -------------------------------------
168 ---------------
172 - usage of the deprecated GUID-based WMI interface which uses GUIDs instead of WMI device structs
173 - bypassing of the WMI subsystem when talking to WMI devices
174 - WMI drivers which cannot be instantiated multiple times.
181 Documentation/process/coding-style.rst. The checkpatch utility can catch many common coding style
186   ./scripts/checkpatch.pl --strict <path to driver file>