[0/9] hwmon: (dell-smm) Add support for WMI SMM interface

Message

Armin Wolf Nov. 3, 2023, 6:57 p.m. UTC

This patch series adds support for an alternative SMM calling
backend to the dell-smm-hwmon driver. The reason for this is
that on some modern machines, the legacy SMM calling interface
does not work anymore and the SMM handler can be called over
ACPI WMI instead.

The first four patches prepare the driver by allowing to
specify different SMM calling backends, and by moving most of
the DMI handling into i8k_init() so that the DMI tables can
keep their __initconst attributes (the WMI SMM backend driver
does not probe at module init time). The fifth patch does some
minor cleanup, while the next three patches implement the new
WMI SMM calling backend. The last patch adds the machine of
the user who requested and tested the changes to the fan control
whitelist.

If the driver does not detect the legacy SMM interface, either
because the machine is not whitelisted or because the SMM handler
does not react, it registers an WMI driver which will then bound
to the WMI SMM interface and do the remaining initialization.

The deprecated procfs interface is not supported when using the
WMI SMM calling backend for the following reason: the WMI driver
can potentially be instantiated multiple times while the deprectated
procfs interface cannot. This should not cause any regressions
because on machines supporting only the WMI SMM interface, the
driver would, until now, not load anyway.

All patches where tested on a Dell Inspiron 3505 and a Dell
OptiPlex 7000.

Armin Wolf (9):
  hwmon: (dell-smm) Prepare for multiple SMM calling backends
  hwmon: (dell-smm) Move blacklist handling to module init
  hwmon: (dell-smm) Move whitelist handling to module init
  hwmon: (dell-smm) Move DMI config handling to module init
  hwmon: (dell-smm) Move config entries out of i8k_dmi_table
  hwmon: (dell-smm) Introduce helper function for data init
  hwmon: (dell-smm) Add support for WMI SMM interface
  hwmon: (dell-smm) Document the WMI SMM interface
  hwmon: (dell-smm) Add Optiplex 7000 to fan control whitelist

 Documentation/hwmon/dell-smm-hwmon.rst |  33 +-
 drivers/hwmon/Kconfig                  |   1 +
 drivers/hwmon/dell-smm-hwmon.c         | 569 +++++++++++++++++--------
 drivers/platform/x86/wmi.c             |   1 +
 4 files changed, 414 insertions(+), 190 deletions(-)

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2.39.2