linux/Documentation/hwmon/thmc50
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   1Kernel driver thmc50
   2=====================
   3
   4Supported chips:
   5  * Analog Devices ADM1022
   6    Prefix: 'adm1022'
   7    Addresses scanned: I2C 0x2c - 0x2e
   8    Datasheet: http://www.analog.com/en/prod/0,2877,ADM1022,00.html
   9  * Texas Instruments THMC50
  10    Prefix: 'thmc50'
  11    Addresses scanned: I2C 0x2c - 0x2e
  12    Datasheet: http://www.ti.com/ 
  13
  14Author: Krzysztof Helt <krzysztof.h1@wp.pl>
  15
  16This driver was derived from the 2.4 kernel thmc50.c source file.
  17
  18Credits:
  19  thmc50.c (2.4 kernel):
  20        Frodo Looijaard <frodol@dds.nl>
  21        Philip Edelbrock <phil@netroedge.com>
  22
  23Module Parameters
  24-----------------
  25
  26* adm1022_temp3: short array
  27  List of adapter,address pairs to force chips into ADM1022 mode with
  28  second remote temperature. This does not work for original THMC50 chips.
  29
  30Description
  31-----------
  32
  33The THMC50 implements: an internal temperature sensor, support for an
  34external diode-type temperature sensor (compatible w/ the diode sensor inside
  35many processors), and a controllable fan/analog_out DAC. For the temperature
  36sensors, limits can be set through the appropriate Overtemperature Shutdown
  37register and Hysteresis register. Each value can be set and read to half-degree
  38accuracy.  An alarm is issued (usually to a connected LM78) when the
  39temperature gets higher then the Overtemperature Shutdown value; it stays on
  40until the temperature falls below the Hysteresis value. All temperatures are in
  41degrees Celsius, and are guaranteed within a range of -55 to +125 degrees.
  42
  43The THMC50 only updates its values each 1.5 seconds; reading it more often
  44will do no harm, but will return 'old' values.
  45
  46The THMC50 is usually used in combination with LM78-like chips, to measure
  47the temperature of the processor(s).
  48
  49The ADM1022 works the same as THMC50 but it is faster (5 Hz instead of
  501 Hz for THMC50). It can be also put in a new mode to handle additional
  51remote temperature sensor. The driver use the mode set by BIOS by default.
  52
  53In case the BIOS is broken and the mode is set incorrectly, you can force
  54the mode with additional remote temperature with adm1022_temp3 parameter.
  55A typical symptom of wrong setting is a fan forced to full speed.
  56
  57Driver Features
  58---------------
  59
  60The driver provides up to three temperatures:
  61
  62temp1           -- internal
  63temp2           -- remote
  64temp3           -- 2nd remote only for ADM1022
  65
  66pwm1            -- fan speed (0 = stop, 255 = full)
  67pwm1_mode       -- always 0 (DC mode)
  68
  69The value of 0 for pwm1 also forces FAN_OFF signal from the chip,
  70so it stops fans even if the value 0 into the ANALOG_OUT register does not.
  71
  72The driver was tested on Compaq AP550 with two ADM1022 chips (one works
  73in the temp3 mode), five temperature readings and two fans.
  74
  75
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