Kernel driver max31785

Supported chips:

Author: Andrew Jeffery <andrew@aj.id.au>

Description

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

For dual-rotor configurations the MAX31785A exposes the second rotor tachometer readings in attributes fan[5-8]_input. By contrast the MAX31785 only exposes the slowest rotor measurement, and does so in the fan[1-4]_input attributes.

Usage Notes

This driver does not probe for PMBus devices. You will have to instantiate devices explicitly.

Sysfs attributes

fan[1-4]_alarm

Fan alarm.

fan[1-4]_fault

Fan fault.

fan[1-8]_input

Fan RPM. On the MAX31785A, inputs 5-8 correspond to the second rotor of fans 1-4

fan[1-4]_target

Fan input target

in[1-6]_crit

Critical maximum output voltage

in[1-6]_crit_alarm

Output voltage critical high alarm

in[1-6]_input

Measured output voltage

in[1-6]_label

“vout[18-23]”

in[1-6]_lcrit

Critical minimum output voltage

in[1-6]_lcrit_alarm

Output voltage critical low alarm

in[1-6]_max

Maximum output voltage

in[1-6]_max_alarm

Output voltage high alarm

in[1-6]_min

Minimum output voltage

in[1-6]_min_alarm

Output voltage low alarm

pwm[1-4]

Fan target duty cycle (0..255)

pwm[1-4]_enable

0: Full-speed 1: Manual PWM control 2: Automatic PWM (tach-feedback RPM fan-control) 3: Automatic closed-loop (temp-feedback fan-control)

temp[1-11]_crit

Critical high temperature

temp[1-11]_crit_alarm

Chip temperature critical high alarm

temp[1-11]_input

Measured temperature

temp[1-11]_max

Maximum temperature

temp[1-11]_max_alarm

Chip temperature high alarm