Documentation/hwmon/max31785.rst

   1 Kernel driver max31785
   2 ======================
   3
   4 Supported chips:
   5
   6   * Maxim MAX31785, MAX31785A
   7
   8     Prefix: 'max31785' or 'max31785a'
   9
  10     Addresses scanned: -
  11
  12     Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
  13
  14 Author: Andrew Jeffery <andrew@aj.id.au>
  15
  16 Description
  17 -----------
  18
  19 The Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel fan
  20 management with temperature and remote voltage sensing. Various fan control
  21 features are provided, including PWM frequency control, temperature hysteresis,
  22 dual tachometer measurements, and fan health monitoring.
  23
  24 For dual-rotor configurations the MAX31785A exposes the second rotor tachometer
  25 readings in attributes fan[5-8]_input. By contrast the MAX31785 only exposes
  26 the slowest rotor measurement, and does so in the fan[1-4]_input attributes.
  27
  28 Usage Notes
  29 -----------
  30
  31 This driver does not probe for PMBus devices. You will have to instantiate
  32 devices explicitly.
  33
  34 Sysfs attributes
  35 ----------------
  36
  37 ======================= =======================================================
  38 fan[1-4]_alarm          Fan alarm.
  39 fan[1-4]_fault          Fan fault.
  40 fan[1-8]_input          Fan RPM. On the MAX31785A, inputs 5-8 correspond to the
  41                         second rotor of fans 1-4
  42 fan[1-4]_target         Fan input target
  43
  44 in[1-6]_crit            Critical maximum output voltage
  45 in[1-6]_crit_alarm      Output voltage critical high alarm
  46 in[1-6]_input           Measured output voltage
  47 in[1-6]_label           "vout[18-23]"
  48 in[1-6]_lcrit           Critical minimum output voltage
  49 in[1-6]_lcrit_alarm     Output voltage critical low alarm
  50 in[1-6]_max             Maximum output voltage
  51 in[1-6]_max_alarm       Output voltage high alarm
  52 in[1-6]_min             Minimum output voltage
  53 in[1-6]_min_alarm       Output voltage low alarm
  54
  55 pwm[1-4]                Fan target duty cycle (0..255)
  56 pwm[1-4]_enable         0: Full-speed
  57                         1: Manual PWM control
  58                         2: Automatic PWM (tach-feedback RPM fan-control)
  59                         3: Automatic closed-loop (temp-feedback fan-control)
  60
  61 temp[1-11]_crit         Critical high temperature
  62 temp[1-11]_crit_alarm   Chip temperature critical high alarm
  63 temp[1-11]_input        Measured temperature
  64 temp[1-11]_max          Maximum temperature
  65 temp[1-11]_max_alarm    Chip temperature high alarm
  66 ======================= =======================================================