Kernel driver `lm80.o'
======================

Status: Complete and tested

Supported chips:
  * National Semiconductors LM80
    Prefix `lm80'
    Addresses scanned: I2C 0x20 - 0x2f (inclusive)

Author: Frodo Looijaard <frodol@dds.nl> and Philip Edelbrock
        <phil@netroedge.com>


Module Parameters
-----------------

* force: short array (min = 1, max = 48)
  List of adapter,address pairs to boldly assume to be present
* force_lm80: short array (min = 1, max = 48)
  List of adapter,address pairs which are unquestionably assumed to contain
  a `lm80' chip
* ignore: short array (min = 1, max = 48)
  List of adapter,address pairs not to scan
* ignore_range: short array (min = 1, max = 48)
  List of adapter,start-addr,end-addr triples not to scan
* probe: short array (min = 1, max = 48)
  List of adapter,address pairs to scan additionally
* probe_range: short array (min = 1, max = 48)
  List of adapter,start-addr,end-addr triples to scan additionally


Description
-----------

This driver implements support for the National Semiconductors LM80.
It is descibed as a `Serial Interface ACPI-Compatible Microprocessor
System Hardware Monitor'.

The LM80 implements one temperature sensor, two FAN rotation speed sensors,
seven voltage sensors, alarms, and some miscellaneous stuff.

Temperatures are measured in degrees Celcius. There are two sets of limits
which operate independently. When the HOT Temperature Limit is crossed,
this will cause an alarm that will be reasserted until the temperature
drops below the HOT Hysteresis. The Overtemperature Shotdown (OS) limits
should work in the same way (but this must be checked; the datasheet
is unclear about this). Measurements are guaranteed between -55 and
+125 degrees. The current temperature measurement has a resolution of
0.0625 degrees; the limits have a resolution of 1 degree.

FAN rotation speeds are reported in RPM (rotations per minute). An alarm is
triggered if the rotation speed has dropped below a programmable limit. FAN 
readings can be divided by a programmable divider (1, 2, 4 or 8) to give
the readings more range or accuracy. This is important because some FANs
report only one 'tick' each rotation, while others report two - making
all readings twice as high. Not all RPM values can accurately be represented,
so some rounding is done. With a divider of 2, the lowest representable
value is around 2600 RPM.

Voltage ensors (also known as IN sensors) report their values in volts.
An alarm is triggered if the voltage has crossed a programmable minimum 
or maximum limit. Note that minimum in this case always means 'closest to
zero'; this is important for negative voltage measurements. All voltage
inputs can measure voltages between 0 and 2.55 volts, with a resolution
of 0.01 volt.

If an alarm triggers, it will remain triggered until the hardware register
is read at least once. This means that the cause for the alarm may 
already have disappeared!  Note that in the current implementation, all
hardware registers are read whenever any data is read (unless it is less
than 2.0 seconds since the last update). This means that you can easily
miss once-only alarms.

The LM80 only updates its values each 1.5 seconds; reading it more often
will do no harm, but will return 'old' values.


Chip Features
-------------

Chip `lm80'
          LABEL     LABEL CLASS   COMPUTE CLASS ACCESS MAGNITUDE
            in0            NONE            NONE      R     2
            in1            NONE            NONE      R     2
            in2            NONE            NONE      R     2
            in3            NONE            NONE      R     2
            in4            NONE            NONE      R     2
            in5            NONE            NONE      R     2
            in6            NONE            NONE      R     2
        in0_min             in0             in0      RW    2
        in1_min             in1             in1      RW    2
        in2_min             in2             in2      RW    2
        in3_min             in3             in3      RW    2
        in4_min             in4             in4      RW    2
        in5_min             in5             in5      RW    2
        in6_min             in6             in6      RW    2
        in0_max             in0             in0      RW    2
        in1_max             in1             in1      RW    2
        in2_max             in2             in2      RW    2
        in3_max             in3             in3      RW    2
        in4_max             in4             in4      RW    2
        in5_max             in5             in5      RW    2
        in6_max             in6             in6      RW    2
           fan1            NONE            NONE      R     0
           fan2            NONE            NONE      R     0
       fan1_min            fan1            NONE      RW    0
       fan2_min            fan2            NONE      RW    0
           temp            NONE            NONE      R     2
  temp_hot_hyst            temp            temp      RW    2
   temp_hot_max            temp            temp      RW    2
   temp_os_hyst            temp            temp      RW    2
    temp_os_max            temp            temp      RW    2
       fan1_div            fan1            NONE      RW    0
       fan2_div            fan2            NONE      RW    0
         alarms            NONE            NONE      R     0

          LABEL                           FEATURE SYMBOL     SYSCTL FILE:OFFSET
            in0                         SENSORS_LM80_IN0             in0:3
            in1                         SENSORS_LM80_IN1             in1:3
            in2                         SENSORS_LM80_IN2             in2:3
            in3                         SENSORS_LM80_IN3             in3:3
            in4                         SENSORS_LM80_IN4             in4:3
            in5                         SENSORS_LM80_IN5             in5:3
            in6                         SENSORS_LM80_IN6             in6:3
        in0_min                     SENSORS_LM80_IN0_MIN             in0:1
        in1_min                     SENSORS_LM80_IN1_MIN             in1:1
        in2_min                     SENSORS_LM80_IN2_MIN             in2:1
        in3_min                     SENSORS_LM80_IN3_MIN             in3:1
        in4_min                     SENSORS_LM80_IN4_MIN             in4:1
        in5_min                     SENSORS_LM80_IN5_MIN             in5:1
        in6_min                     SENSORS_LM80_IN6_MIN             in6:1
        in0_max                     SENSORS_LM80_IN0_MAX             in0:2
        in1_max                     SENSORS_LM80_IN1_MAX             in1:2
        in2_max                     SENSORS_LM80_IN2_MAX             in2:2
        in3_max                     SENSORS_LM80_IN3_MAX             in3:2
        in4_max                     SENSORS_LM80_IN4_MAX             in4:2
        in5_max                     SENSORS_LM80_IN5_MAX             in5:2
        in6_max                     SENSORS_LM80_IN6_MAX             in6:2
           fan1                        SENSORS_LM80_FAN1            fan1:2
           fan2                        SENSORS_LM80_FAN2            fan2:2
       fan1_min                    SENSORS_LM80_FAN1_MIN            fan1:1
       fan2_min                    SENSORS_LM80_FAN2_MIN            fan2:1
           temp                        SENSORS_LM80_TEMP            temp:5
  temp_hot_hyst               SENSORS_LM80_TEMP_HOT_HYST            temp:2
   temp_hot_max                SENSORS_LM80_TEMP_HOT_MAX            temp:1
   temp_os_hyst                SENSORS_LM80_TEMP_OS_HYST            temp:4
    temp_os_max                 SENSORS_LM80_TEMP_OS_MAX            temp:3
       fan1_div                    SENSORS_LM80_FAN1_DIV         fan_div:1
       fan2_div                    SENSORS_LM80_FAN2_DIV         fan_div:2
         alarms                      SENSORS_LM80_ALARMS          alarms:1
