[SMCSuperIO] Implement NCT6798D-R SuperIO chip

[dreamwhite]

The Nuvoton NCT6798D-R is a Super I/O chip commonly found on various ASUS motherboards such as:

• ASUS ROG Strix B550-F Gaming (Wi-Fi)
• ASUS TUF Gaming B550-Plus
• ASUS ROG Zenith II Extreme

At the time of writing, SMCSuperIO kext (bundled with VirtualSMC 1.3.4) doesn't support it (therefore cannot control fan speed) neither I found any user reporting proof of it working (therefore I suspect no one has ever tried making it working).

This chip is very similar to the Nuvoton NCT6796D Super I/O chip which datasheet is publicly available here.

Can you please share a bullet-proof guide on how to read the proper details from the datasheet and how to eventually implement it on SMCSuperIO for both reading and writing (e.g. fan speed)?

I gave a look at the source code and Tachometer array must be populed with:

• Name
• ReadValue

properties.

Actually speaking for NCT6798D-R, there's a .plist configuration file which defines the various sensors: https://github.com/acidanthera/VirtualSMC/blob/master/Sensors/SMCSuperIO/Resources/NCT6796D-9BD.plist

But there aren't yet the ReadValue properties.

Am I misinterpreting how does the .plist for each Super I/O chip work?

Greetings
dreamwhite