LXR linux/Documentation/hwmon/emc1403.rst

   1Kernel driver emc1403
   2=====================
   3
   4Supported chips:
   5
   6  * SMSC / Microchip EMC1402, EMC1412
   7
   8    Addresses scanned: I2C 0x18, 0x1c, 0x29, 0x4c, 0x4d, 0x5c
   9
  10    Prefix: 'emc1402'
  11
  12    Datasheets:
  13
  14        - http://ww1.microchip.com/downloads/en/DeviceDoc/1412.pdf
  15        - https://ww1.microchip.com/downloads/en/DeviceDoc/1402.pdf
  16
  17  * SMSC / Microchip EMC1403, EMC1404, EMC1413, EMC1414
  18
  19    Addresses scanned: I2C 0x18, 0x29, 0x4c, 0x4d
  20
  21    Prefix: 'emc1403', 'emc1404'
  22
  23    Datasheets:
  24
  25        - http://ww1.microchip.com/downloads/en/DeviceDoc/1403_1404.pdf
  26        - http://ww1.microchip.com/downloads/en/DeviceDoc/1413_1414.pdf
  27
  28  * SMSC / Microchip EMC1422
  29
  30    Addresses scanned: I2C 0x4c
  31
  32    Prefix: 'emc1422'
  33
  34    Datasheet:
  35
  36        - https://ww1.microchip.com/downloads/en/DeviceDoc/1422.pdf
  37
  38  * SMSC / Microchip EMC1423, EMC1424
  39
  40    Addresses scanned: I2C 0x4c
  41
  42    Prefix: 'emc1423', 'emc1424'
  43
  44    Datasheet:
  45
  46        - https://ww1.microchip.com/downloads/en/DeviceDoc/1423_1424.pdf
  47
  48Author:
  49    Kalhan Trisal <kalhan.trisal@intel.com
  50
  51
  52Description
  53-----------
  54
  55The Standard Microsystems Corporation (SMSC) / Microchip EMC14xx chips
  56contain up to four temperature sensors. EMC14x2 support two sensors
  57(one internal, one external). EMC14x3 support three sensors (one internal,
  58two external), and EMC14x4 support four sensors (one internal, three
  59external).
  60
  61The chips implement three limits for each sensor: low (tempX_min), high
  62(tempX_max) and critical (tempX_crit.) The chips also implement an
  63hysteresis mechanism which applies to all limits. The relative difference
  64is stored in a single register on the chip, which means that the relative
  65difference between the limit and its hysteresis is always the same for
  66all three limits.
  67
  68This implementation detail implies the following:
  69
  70* When setting a limit, its hysteresis will automatically follow, the
  71  difference staying unchanged. For example, if the old critical limit
  72  was 80 degrees C, and the hysteresis was 75 degrees C, and you change
  73  the critical limit to 90 degrees C, then the hysteresis will
  74  automatically change to 85 degrees C.
  75* The hysteresis values can't be set independently. We decided to make
  76  only temp1_crit_hyst writable, while all other hysteresis attributes
  77  are read-only. Setting temp1_crit_hyst writes the difference between
  78  temp1_crit_hyst and temp1_crit into the chip, and the same relative
  79  hysteresis applies automatically to all other limits.
  80* The limits should be set before the hysteresis.
  81