The Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel
fan management with temperature and remote voltage sensing. It supports
various fan control features, including PWM frequency control, temperature
hysteresis, dual tachometer measurements, and fan health monitoring.

This patch presents a basic driver using only the existing features of the
PMBus subsystem.
Signed-off-by: NAndrew Jeffery <andrew@aj.id.au>
[groeck: Modified description to clarify that fan control is not yet provided]
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>