[PATCH v2 1/4] platform/x86: Add lenovo-wmi drivers Documentation

["Derek J. Clark" <derekjohn.clark@gmail.com>]

Adds documentation for all lenovo-wmi* drivers.

v2:
- Update description of Custom Profile to include the need to manually
  set it.
- Remove all references to Legion hardware.
- Add section for lemovo-wmi-camera.c driver as it follows the same
  naming convention.

Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>
---
 Documentation/wmi/devices/lenovo-wmi.rst | 104 +++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 Documentation/wmi/devices/lenovo-wmi.rst

diff --git a/Documentation/wmi/devices/lenovo-wmi.rst b/Documentation/wmi/devices/lenovo-wmi.rst
new file mode 100644
index 000000000000..62c2ec9505bd
--- /dev/null
+++ b/Documentation/wmi/devices/lenovo-wmi.rst
@@ -0,0 +1,104 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+======================================================
+Lenovo WMI Interface Drivers (lenovo-wmi)
+======================================================
+
+Introduction
+============
+Lenovo WMI interfaces are broken up into multiple GUIDs, some of which
+require cross-references between GUIDs for some functionality. The "Custom
+Mode" interface is a legacy interface for managing and displaying CPU & GPU
+power and hwmon settings and readings. The "Other Method" interface is a
+modern interface that replaces most "Custom Mode" interface methods. The
+"GameZone" interface adds advanced features such as fan profiles and
+overclocking. The "Lighting" interface adds control of various status
+lights related to different hardware components.
+
+Each interface has a different data structure associated with it that
+provides detailed information about each attribute provided by the
+interface. These data structs are retrieved from additional WMI device
+data block GUIDs:
+ - "Custom Mode" uses LENOVO_FAN_TABLE_DATA, LENOVO_FAN_TEST_DATA,
+   LENOVO_CPU_OVERCLOCKING_DATA, LENOVO_DISCRETE_DATA, and
+   LENOVO_GPU_OVERCLOCKING_DATA depending on the feature.
+ - "Other Method" uses LENOVO_CAPABILITY_DATA_00,
+   LENOVO_CAPABILITY_DATA_01, and LENOVO_CAPABILITY_DATA_02 depending on
+   the feature.
+ - "GameZone" uses LENOVO_GAMEZONE_CPU_OC_DATA and
+   LENOVO_GAMEZONE_GPU_OC_DATA depending on the feature.
+ - The "Lighting" interface uses LENOVO_LIGHTING_DATA.
+
+.. note::
+   Currently only the "GameZone", "Other Method", and
+   LENOVO_CAPABILITY_DATA_01 interfaces are implemented by these drivers.
+
+GameZone
+--------
+WMI GUID "887B54E3-DDDC-4B2C-8B88-68A26A8835D0"
+
+The GameZone WMI interface provides platform-profile and fan curve settings
+for devices that fall under the "Gaming Series" of Lenovo devices.
+
+The following platform profiles are supported:
+ - quiet
+ - balanced
+ - performance
+ - custom
+
+Custom Profile
+~~~~~~~~~~~~~~
+The custom profile represents a hardware mode on Lenovo devices that enables
+user modifications to Package Power Tracking (PPT) settings. When an
+attribute exposed by the "Other Method" WMI interface is to be modified,
+the GameZone driver must first be switched to the "custom" profile manually
+or the setting will have no effect. If another profile is set from the list
+of supported profiles, the BIOS will override any user PPT settings when
+switching to that profile.
+
+
+Other Method
+----------
+WMI GUID "DC2A8805-3A8C-41BA-A6F7-092E0089CD3B"
+
+The Other Method WMI interface uses the fw_attributes class to expose
+various WMI attributes provided by the interface in the sysfs. This enables
+CPU and GPU power limit tuning as well as various other attributes for
+devices that fall under the "Gaming Series" of Lenovo devices. Each
+attribute exposed by the Other Method interface has corresponding
+capability data blocks which allow the driver to probe details about the
+attribute. Each attibute has multiple pages, one for each of the platform
+profiles managed by the "GameZone" interface. For all properties only the
+"Custom" profile values are reported by this driver to ensure any userspace
+applications reading them have accurate tunable value ranges. Attributes
+are exposed in sysfs under the following path:
+/sys/class/firmware-attributes/lenovo-wmi-other/attributes
+
+LENOVO_CAPABILITY_DATA_01
+~~~~~~~~~~~~~~~~~~~~~~~~~
+WMI GUID "7A8F5407-CB67-4D6E-B547-39B3BE018154"
+
+The LENOVO_CAPABILITY_DATA_01 interface provides information on various
+power limits of integrated CPU and GPU components.
+
+The following attributes are supported:
+ - ppt_pl1_spl: Platform Profile Tracking Sustained Power Limit
+ - ppt_pl2_sppt: Platform Profile Tracking Slow Package Power Tracking
+ - ppt_pl3_fppt: Platform Profile Tracking Fast Package Power Tracking
+
+Each attribute has the following properties:
+ - current_value
+ - default_value
+ - display_name
+ - max_value
+ - min_value
+ - scalar_increment
+ - type
+
+
+ Camera
+ ______
+ WMI GUID "50C76F1F-D8E4-D895-0A3D-62F4EA400013"
+
+ The Camera driver provides WMI event notifications for camera button
+ toggling.
+
-- 
2.47.0