Kernel driver `w83627ehf.o'
===========================

Status: Stable; some missing features.

Supported chips:
  * Winbond W83627EHF/EHG (ISA access ONLY)
    Prefix: 'w83627ehf'
    Addresses scanned: ISA address retrieved from Super I/O registers
    Datasheet: http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83627EHF_%20W83627EHGb.pdf

Authors:
        Jean Delvare <khali@linux-fr.org>
        Yuan Mu (Winbond)
        Rudolf Marek <r.marek@assembler.cz>
        David Hubbard <david.c.hubbard@gmail.com>

Thanks to Observit and Bernardo Motta for providing a motherboard, CPU
and memory that made it possible to backport the w83627ehf driver from
Linux 2.6 to Linux 2.4.


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

This driver implements support for the Winbond W83627EHF and W83627EHG
super I/O chips. Support for the W83627DHG isn't included, but could be
easily added if needed.

The chips implement three temperature sensors, five fan rotation speed
sensors, ten analog voltage sensors, alarms with beep warnings (control
unimplemented), some automatic fan regulation strategies (unimplemented)
and manual fan speed control.

Temperatures are measured in degrees Celsius and measurement resolution is
1 degree Celsius for temp1 and 0.5 degee Celsius for temp2 and temp3. An
alarm is triggered when the temperature gets higher than high limit; it
stays on until the temperature falls below the hysteresis value.

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, 8, 16, 32, 64 or
128) to give the readings more range or accuracy. The driver sets the most
suitable fan divisor itself. Some fans might not be present because they
share pins with other functions.

Voltage sensors (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.


Fan speed control
-----------------

The chips support 4 different fan speed control modes. The currently
selected mode can be read from (and written to) the second value of
files pwm[1-4]. Modes are:

  1: Manual mode. The desired fan speed can be written to the first
     value of the pwm[1-4] file, from 0 (stop) to 255 (full speed).
  2: Thermal cruise mode (unimplemented).
  3: Fan speed cuise mode (unimplemented).
  4: Smart Fan III mode (pwm2 and pwm4 only, unimplemented).

While the automatic modes are not implemented by this driver, they can
still be selected, so they will work if (and only if) the BIOS has
programmed the chip with sensible register values.
