Documentation/hwmon/amc6821.rst

   1 Kernel driver amc6821
   2 =====================
   3
   4 Supported chips:
   5
   6         Texas Instruments AMC6821
   7
   8         Prefix: 'amc6821'
   9
  10         Addresses scanned: 0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 0x4c, 0x4d, 0x4e
  11
  12         Datasheet: http://focus.ti.com/docs/prod/folders/print/amc6821.html
  13
  14 Authors:
  15         Tomaz Mertelj <tomaz.mertelj@guest.arnes.si>
  16
  17
  18 Description
  19 -----------
  20
  21 This driver implements support for the Texas Instruments amc6821 chip.
  22 The chip has one on-chip and one remote temperature sensor and one pwm fan
  23 regulator.
  24 The pwm can be controlled either from software or automatically.
  25
  26 The driver provides the following sensor accesses in sysfs:
  27
  28 ======================= ==      ===============================================
  29 temp1_input             ro      on-chip temperature
  30 temp1_min               rw      "
  31 temp1_max               rw      "
  32 temp1_crit              rw      "
  33 temp1_min_alarm         ro      "
  34 temp1_max_alarm         ro      "
  35 temp1_crit_alarm        ro      "
  36
  37 temp2_input             ro      remote temperature
  38 temp2_min               rw      "
  39 temp2_max               rw      "
  40 temp2_crit              rw      "
  41 temp2_min_alarm         ro      "
  42 temp2_max_alarm         ro      "
  43 temp2_crit_alarm        ro      "
  44 temp2_fault             ro      "
  45
  46 fan1_input              ro      tachometer speed
  47 fan1_min                rw      "
  48 fan1_max                rw      "
  49 fan1_fault              ro      "
  50 fan1_div                rw      Fan divisor can be either 2 or 4.
  51
  52 pwm1                    rw      pwm1
  53 pwm1_enable             rw      regulator mode, 1=open loop, 2=fan controlled
  54                                 by remote temperature, 3=fan controlled by
  55                                 combination of the on-chip temperature and
  56                                 remote-sensor temperature,
  57 pwm1_auto_channels_temp ro      1 if pwm_enable==2, 3 if pwm_enable==3
  58 pwm1_auto_point1_pwm    ro      Hardwired to 0, shared for both
  59                                 temperature channels.
  60 pwm1_auto_point2_pwm    rw      This value is shared for both temperature
  61                                 channels.
  62 pwm1_auto_point3_pwm    rw      Hardwired to 255, shared for both
  63                                 temperature channels.
  64
  65 temp1_auto_point1_temp  ro      Hardwired to temp2_auto_point1_temp
  66                                 which is rw. Below this temperature fan stops.
  67 temp1_auto_point2_temp  rw      The low-temperature limit of the proportional
  68                                 range. Below this temperature
  69                                 pwm1 = pwm1_auto_point2_pwm. It can go from
  70                                 0 degree C to 124 degree C in steps of
  71                                 4 degree C. Read it out after writing to get
  72                                 the actual value.
  73 temp1_auto_point3_temp  rw      Above this temperature fan runs at maximum
  74                                 speed. It can go from temp1_auto_point2_temp.
  75                                 It can only have certain discrete values
  76                                 which depend on temp1_auto_point2_temp and
  77                                 pwm1_auto_point2_pwm. Read it out after
  78                                 writing to get the actual value.
  79
  80 temp2_auto_point1_temp  rw      Must be between 0 degree C and 63 degree C and
  81                                 it defines the passive cooling temperature.
  82                                 Below this temperature the fan stops in
  83                                 the closed loop mode.
  84 temp2_auto_point2_temp  rw      The low-temperature limit of the proportional
  85                                 range. Below this temperature
  86                                 pwm1 = pwm1_auto_point2_pwm. It can go from
  87                                 0 degree C to 124 degree C in steps
  88                                 of 4 degree C.
  89
  90 temp2_auto_point3_temp  rw      Above this temperature fan runs at maximum
  91                                 speed. It can only have certain discrete
  92                                 values which depend on temp2_auto_point2_temp
  93                                 and pwm1_auto_point2_pwm. Read it out after
  94                                 writing to get actual value.
  95 ======================= ==      ===============================================
  96
  97
  98 Module parameters
  99 -----------------
 100
 101 If your board has a BIOS that initializes the amc6821 correctly, you should
 102 load the module with: init=0.
 103
 104 If your board BIOS doesn't initialize the chip, or you want
 105 different settings, you can set the following parameters:
 106
 107 - init=1,
 108 - pwminv: 0 default pwm output, 1 inverts pwm output.