Kernel driver ds620
  ===================
  
  Supported chips:
    * Dallas Semiconductor DS620
      Prefix: 'ds620'
      Datasheet: Publicly available at the Dallas Semiconductor website
                 http://www.dalsemi.com/
  
  Authors:
          Roland Stigge <stigge@antcom.de>
          based on ds1621.c by
          Christian W. Zuckschwerdt <zany@triq.net>
  
  Description
  -----------
  
  The DS620 is a (one instance) digital thermometer and thermostat. It has both
  high and low temperature limits which can be user defined (i.e.  programmed
  into non-volatile on-chip registers). Temperature range is -55 degree Celsius
  to +125. Between 0 and 70 degree Celsius, accuracy is 0.5 Kelvin. The value
  returned via sysfs displays post decimal positions.
  
  The thermostat function works as follows: When configured via platform_data
  (struct ds620_platform_data) .pomode == 0 (default), the thermostat output pin
  PO is always low. If .pomode == 1, the thermostat is in PO_LOW mode. I.e., the
  output pin PO becomes active when the temperature falls below temp1_min and
  stays active until the temperature goes above temp1_max.
  
  Likewise, with .pomode == 2, the thermostat is in PO_HIGH mode. I.e., the PO
  output pin becomes active when the temperature goes above temp1_max and stays
  active until the temperature falls below temp1_min.
  
  The PO output pin of the DS620 operates active-low.