Kernel driver nct6683
=====================

Supported chips:

  * Nuvoton NCT6683D/NCT6687D

    Prefix: 'nct6683'

    Addresses scanned: ISA address retrieved from Super I/O registers

    Datasheet: Available from Nuvoton upon request

Authors:

	Guenter Roeck <linux@roeck-us.net>

Description
-----------

This driver implements support for the Nuvoton NCT6683D eSIO chip.

The chips implement up to shared 32 temperature and voltage sensors.
It supports up to 16 fan rotation sensors and up to 8 fan control engines.

Temperatures are measured in degrees Celsius. Measurement resolution is
0.5 degrees C.

Voltage sensors (also known as IN sensors) report their values in millivolts.

Fan rotation speeds are reported in RPM (rotations per minute).

Usage Note
----------

Limit register locations on Intel boards with EC firmware version 1.0
build date 04/03/13 do not match the register locations in the Nuvoton
datasheet. Nuvoton confirms that Intel uses a special firmware version
with different register addresses. The specification describing the Intel
firmware is held under NDA by Nuvoton and Intel and not available
to the public.

Some of the register locations can be reverse engineered; others are too
well hidden. Given this, writing any values from the operating system is
considered too risky with this firmware and has been disabled. All limits
must all be written from the BIOS.

The driver has only been tested with the Intel firmware, and by default
only instantiates on Intel boards. To enable it on non-Intel boards,
set the 'force' module parameter to 1.

Tested Boards and Firmware Versions
-----------------------------------

The driver has been reported to work with the following boards and
firmware versions.

=============== ===============================================
Board		Firmware version
=============== ===============================================
Intel DH87RL	NCT6683D EC firmware version 1.0 build 04/03/13
Intel DH87MC	NCT6683D EC firmware version 1.0 build 04/03/13
Intel DB85FL	NCT6683D EC firmware version 1.0 build 04/03/13
ASRock X570	NCT6683D EC firmware version 1.0 build 06/28/19
MSI B550	NCT6687D EC firmware version 1.0 build 05/07/20
=============== ===============================================
