[PATCH v3 0/6] platform/x86: lenovo-wmi-{capdata,other}: Add HWMON for fan speed

[Rong Zhang <i@rong.moe>]

Lenovo WMI Other Mode interface also supports querying or setting fan
speed RPM. This capability is decribed by LENOVO_CAPABILITY_DATA_00.
Besides, LENOVO_FAN_TEST_DATA provides reference data for self-test of
cooling fans, including minimum and maximum fan speed RPM.

This patchset turns lenovo-wmi-capdata01 into a unified driver (now
named lenovo-wmi-capdata) for LENOVO_CAPABILITY_DATA_{00,01} and
LENOVO_FAN_TEST_DATA; then adds HWMON support for lenovo-wmi-other:

 - fanX_enable: enable/disable the fan (tunable)
 - fanX_input: current RPM
 - fanX_max: maximum RPM
 - fanX_min: minimum RPM
 - fanX_target: target RPM (tunable)

This implementation doesn't require all capability data to be available,
and is capable to expose interfaces accordingly:

 - Having LENOVO_CAPABILITY_DATA_00: exposes fanX_{enable,input,target}
 - Having LENOVO_CAPABILITY_DATA_01: exposes firmware_attributes
 - Having LENOVO_FAN_TEST_DATA: exposes fanX_{max,min}

Signed-off-by: Rong Zhang <i@rong.moe>
Reviewed-by: Derek J. Clark <derekjohn.clark@gmail.com>
Tested-by: Derek J. Clark <derekjohn.clark@gmail.com>

Changes in v2:
- Add a workaround for ACPI methods that return a 4B buffer for u32
  (thanks Armin Wolf)
- Fix function documentation (thanks kernel test bot)
- Reword documentation (thanks Derek J. Clark)
- Squash min/max reporting patch into the initial HWMON one (ditto)
- Query 0x04050000 for interface availability (ditto)
  - New parameter "expose_all_fans" to skip this check
- Enforce min/max RPM constraint on set (ditto)
  - New parameter "relax_fan_constraint" to disable this behavior
  - Drop parameter "ignore_fan_cap", superseded by the next one
  - New parameter "expose_all_fans" to expose fans w/o such data
- Assume auto mode on probe (ditto)
- Do not register HWMON device if no fan can be exposed
- fanX_target: Return -EBUSY instead of raw target value when fan stops
- Link to v1: https://lore.kernel.org/r/20251019210450.88830-1-i@rong.moe/

Changes in v3:
- Fix grammar (thanks Derek J. Clark)
- Link to v2: https://lore.kernel.org/r/20251030193955.107148-1-i@rong.moe/

Rong Zhang (6):
  platform/x86: lenovo-wmi-helpers: Convert returned 4B buffer into u32
  platform/x86: Rename lenovo-wmi-capdata01 to lenovo-wmi-capdata
  platform/x86: lenovo-wmi-{capdata,other}: Support multiple Capability
    Data
  platform/x86: lenovo-wmi-capdata: Add support for Capability Data 00
  platform/x86: lenovo-wmi-capdata: Add support for Fan Test Data
  platform/x86: lenovo-wmi-other: Add HWMON for fan speed RPM

 .../wmi/devices/lenovo-wmi-other.rst          |  43 +-
 drivers/platform/x86/lenovo/Kconfig           |   5 +-
 drivers/platform/x86/lenovo/Makefile          |   2 +-
 drivers/platform/x86/lenovo/wmi-capdata.c     | 545 ++++++++++++++++++
 drivers/platform/x86/lenovo/wmi-capdata.h     |  46 ++
 drivers/platform/x86/lenovo/wmi-capdata01.c   | 302 ----------
 drivers/platform/x86/lenovo/wmi-capdata01.h   |  25 -
 drivers/platform/x86/lenovo/wmi-helpers.c     |  21 +-
 drivers/platform/x86/lenovo/wmi-other.c       | 501 +++++++++++++++-
 9 files changed, 1134 insertions(+), 356 deletions(-)
 create mode 100644 drivers/platform/x86/lenovo/wmi-capdata.c
 create mode 100644 drivers/platform/x86/lenovo/wmi-capdata.h
 delete mode 100644 drivers/platform/x86/lenovo/wmi-capdata01.c
 delete mode 100644 drivers/platform/x86/lenovo/wmi-capdata01.h


base-commit: d127176862a93c4b3216bda533d2bee170af5e71
-- 
2.51.0