Documentation/hwmon/w83791d

Kernel driver w83791d
=====================

Supported chips:
  * Winbond W83791D
    Prefix: 'w83791d'
    Addresses scanned: I2C 0x2c - 0x2f
    Datasheet: http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83791D_W83791Gb.pdf

Author: Charles Spirakis <bezaur@gmail.com>

This driver was derived from the w83781d.c and w83792d.c source files.

Credits:
  w83781d.c:
    Frodo Looijaard <frodol@dds.nl>,
    Philip Edelbrock <phil@netroedge.com>,
    and Mark Studebaker <mdsxyz123@yahoo.com>
  w83792d.c:
    Chunhao Huang <DZShen@Winbond.com.tw>,
    Rudolf Marek <r.marek@sh.cvut.cz>

Additional contributors:
    Sven Anders <anders@anduras.de>

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

* init boolean
  (default 0)
  Use 'init=1' to have the driver do extra software initializations.
  The default behavior is to do the minimum initialization possible
  and depend on the BIOS to properly setup the chip. If you know you
  have a w83791d and you're having problems, try init=1 before trying
  reset=1.

* reset boolean
  (default 0)
  Use 'reset=1' to reset the chip (via index 0x40, bit 7). The default
  behavior is no chip reset to preserve BIOS settings.

* force_subclients=bus,caddr,saddr,saddr
  This is used to force the i2c addresses for subclients of
  a certain chip. Example usage is `force_subclients=0,0x2f,0x4a,0x4b'
  to force the subclients of chip 0x2f on bus 0 to i2c addresses
  0x4a and 0x4b.


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

This driver implements support for the Winbond W83791D chip. The W83791G
chip appears to be the same as the W83791D but is lead free.

Detection of the chip can sometimes be foiled because it can be in an
internal state that allows no clean access (Bank with ID register is not
currently selected). If you know the address of the chip, use a 'force'
parameter; this will put it into a more well-behaved state first.

The driver implements three temperature sensors, five fan rotation speed
sensors, and ten voltage sensors.

Temperatures are measured in degrees Celsius and measurement resolution is 1
degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when
the temperature gets higher than the Overtemperature Shutdown value; 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 for fan 1/2/3
and 1, 2, 4, 8, 16, 32, 64 or 128 for fan 4/5) to give the readings more
range or accuracy.

Voltage sensors (also known as IN sensors) report their values in millivolts.
An alarm is triggered if the voltage has crossed a programmable minimum
or maximum limit.

The bit ordering for the alarm "realtime status register" and the
"beep enable registers" are different.

in0 (VCORE)  :  alarms: 0x000001 beep_enable: 0x000001
in1 (VINR0)  :  alarms: 0x000002 beep_enable: 0x002000 <== mismatch
in2 (+3.3VIN):  alarms: 0x000004 beep_enable: 0x000004
in3 (5VDD)   :  alarms: 0x000008 beep_enable: 0x000008
in4 (+12VIN) :  alarms: 0x000100 beep_enable: 0x000100
in5 (-12VIN) :  alarms: 0x000200 beep_enable: 0x000200
in6 (-5VIN)  :  alarms: 0x000400 beep_enable: 0x000400
in7 (VSB)    :  alarms: 0x080000 beep_enable: 0x010000 <== mismatch
in8 (VBAT)   :  alarms: 0x100000 beep_enable: 0x020000 <== mismatch
in9 (VINR1)  :  alarms: 0x004000 beep_enable: 0x004000
temp1        :  alarms: 0x000010 beep_enable: 0x000010
temp2        :  alarms: 0x000020 beep_enable: 0x000020
temp3        :  alarms: 0x002000 beep_enable: 0x000002 <== mismatch
fan1         :  alarms: 0x000040 beep_enable: 0x000040
fan2         :  alarms: 0x000080 beep_enable: 0x000080
fan3         :  alarms: 0x000800 beep_enable: 0x000800
fan4         :  alarms: 0x200000 beep_enable: 0x200000
fan5         :  alarms: 0x400000 beep_enable: 0x400000
tart1        :  alarms: 0x010000 beep_enable: 0x040000 <== mismatch
tart2        :  alarms: 0x020000 beep_enable: 0x080000 <== mismatch
tart3        :  alarms: 0x040000 beep_enable: 0x100000 <== mismatch
case_open    :  alarms: 0x001000 beep_enable: 0x001000
user_enable  :  alarms: -------- beep_enable: 0x800000

*** NOTE: It is the responsibility of user-space code to handle the fact
that the beep enable and alarm bits are in different positions when using that
feature of the chip.

When an alarm goes off, you can be warned by a beeping signal through your
computer speaker. It is possible to enable all beeping globally, or only
the beeping for some alarms.

The driver only reads the chip values each 3 seconds; reading them more
often will do no harm, but will return 'old' values.

W83791D TODO:
---------------
Provide a patch for per-file alarms and beep enables as defined in the hwmon
	documentation (Documentation/hwmon/sysfs-interface)
Provide a patch for smart-fan control (still need appropriate motherboard/fans)