linux/Documentation/hwmon/w83791d
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   1Kernel driver w83791d
   2=====================
   3
   4Supported chips:
   5  * Winbond W83791D
   6    Prefix: 'w83791d'
   7    Addresses scanned: I2C 0x2c - 0x2f
   8    Datasheet: http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83791D_W83791Gb.pdf
   9
  10Author: Charles Spirakis <bezaur@gmail.com>
  11
  12This driver was derived from the w83781d.c and w83792d.c source files.
  13
  14Credits:
  15  w83781d.c:
  16    Frodo Looijaard <frodol@dds.nl>,
  17    Philip Edelbrock <phil@netroedge.com>,
  18    and Mark Studebaker <mdsxyz123@yahoo.com>
  19  w83792d.c:
  20    Chunhao Huang <DZShen@Winbond.com.tw>,
  21    Rudolf Marek <r.marek@assembler.cz>
  22
  23Additional contributors:
  24    Sven Anders <anders@anduras.de>
  25    Marc Hulsman <m.hulsman@tudelft.nl>
  26
  27Module Parameters
  28-----------------
  29
  30* init boolean
  31  (default 0)
  32  Use 'init=1' to have the driver do extra software initializations.
  33  The default behavior is to do the minimum initialization possible
  34  and depend on the BIOS to properly setup the chip. If you know you
  35  have a w83791d and you're having problems, try init=1 before trying
  36  reset=1.
  37
  38* reset boolean
  39  (default 0)
  40  Use 'reset=1' to reset the chip (via index 0x40, bit 7). The default
  41  behavior is no chip reset to preserve BIOS settings.
  42
  43* force_subclients=bus,caddr,saddr,saddr
  44  This is used to force the i2c addresses for subclients of
  45  a certain chip. Example usage is `force_subclients=0,0x2f,0x4a,0x4b'
  46  to force the subclients of chip 0x2f on bus 0 to i2c addresses
  47  0x4a and 0x4b.
  48
  49
  50Description
  51-----------
  52
  53This driver implements support for the Winbond W83791D chip. The W83791G
  54chip appears to be the same as the W83791D but is lead free.
  55
  56Detection of the chip can sometimes be foiled because it can be in an
  57internal state that allows no clean access (Bank with ID register is not
  58currently selected). If you know the address of the chip, use a 'force'
  59parameter; this will put it into a more well-behaved state first.
  60
  61The driver implements three temperature sensors, ten voltage sensors,
  62five fan rotation speed sensors and manual PWM control of each fan.
  63
  64Temperatures are measured in degrees Celsius and measurement resolution is 1
  65degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when
  66the temperature gets higher than the Overtemperature Shutdown value; it stays
  67on until the temperature falls below the Hysteresis value.
  68
  69Voltage sensors (also known as IN sensors) report their values in millivolts.
  70An alarm is triggered if the voltage has crossed a programmable minimum
  71or maximum limit.
  72
  73Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
  74triggered if the rotation speed has dropped below a programmable limit. Fan
  75readings can be divided by a programmable divider (1, 2, 4, 8, 16,
  7632, 64 or 128 for all fans) to give the readings more range or accuracy.
  77
  78Each fan controlled is controlled by PWM. The PWM duty cycle can be read and
  79set for each fan separately. Valid values range from 0 (stop) to 255 (full).
  80PWM 1-3 support Thermal Cruise mode, in which the PWMs are automatically
  81regulated to keep respectively temp 1-3 at a certain target temperature.
  82See below for the description of the sysfs-interface.
  83
  84The w83791d has a global bit used to enable beeping from the speaker when an
  85alarm is triggered as well as a bitmask to enable or disable the beep for
  86specific alarms. You need both the global beep enable bit and the
  87corresponding beep bit to be on for a triggered alarm to sound a beep.
  88
  89The sysfs interface to the global enable is via the sysfs beep_enable file.
  90This file is used for both legacy and new code.
  91
  92The sysfs interface to the beep bitmask has migrated from the original legacy
  93method of a single sysfs beep_mask file to a newer method using multiple
  94*_beep files as described in .../Documentation/hwmon/sysfs-interface.
  95
  96A similar change has occurred for the bitmap corresponding to the alarms. The
  97original legacy method used a single sysfs alarms file containing a bitmap
  98of triggered alarms. The newer method uses multiple sysfs *_alarm files
  99(again following the pattern described in sysfs-interface).
 100
 101Since both methods read and write the underlying hardware, they can be used
 102interchangeably and changes in one will automatically be reflected by
 103the other. If you use the legacy bitmask method, your user-space code is
 104responsible for handling the fact that the alarms and beep_mask bitmaps
 105are not the same (see the table below).
 106
 107NOTE: All new code should be written to use the newer sysfs-interface
 108specification as that avoids bitmap problems and is the preferred interface
 109going forward.
 110
 111The driver reads the hardware chip values at most once every three seconds.
 112User mode code requesting values more often will receive cached values.
 113
 114/sys files
 115----------
 116The sysfs-interface is documented in the 'sysfs-interface' file. Only
 117chip-specific options are documented here.
 118
 119pwm[1-3]_enable -       this file controls mode of fan/temperature control for
 120                        fan 1-3. Fan/PWM 4-5 only support manual mode.
 121                            * 1 Manual mode
 122                            * 2 Thermal Cruise mode
 123                            * 3 Fan Speed Cruise mode (no further support)
 124
 125temp[1-3]_target -      defines the target temperature for Thermal Cruise mode.
 126                        Unit: millidegree Celsius
 127                        RW
 128
 129temp[1-3]_tolerance -   temperature tolerance for Thermal Cruise mode.
 130                        Specifies an interval around the target temperature
 131                        in which the fan speed is not changed.
 132                        Unit: millidegree Celsius
 133                        RW
 134
 135Alarms bitmap vs. beep_mask bitmask
 136------------------------------------
 137For legacy code using the alarms and beep_mask files:
 138
 139in0 (VCORE)  :  alarms: 0x000001 beep_mask: 0x000001
 140in1 (VINR0)  :  alarms: 0x000002 beep_mask: 0x002000 <== mismatch
 141in2 (+3.3VIN):  alarms: 0x000004 beep_mask: 0x000004
 142in3 (5VDD)   :  alarms: 0x000008 beep_mask: 0x000008
 143in4 (+12VIN) :  alarms: 0x000100 beep_mask: 0x000100
 144in5 (-12VIN) :  alarms: 0x000200 beep_mask: 0x000200
 145in6 (-5VIN)  :  alarms: 0x000400 beep_mask: 0x000400
 146in7 (VSB)    :  alarms: 0x080000 beep_mask: 0x010000 <== mismatch
 147in8 (VBAT)   :  alarms: 0x100000 beep_mask: 0x020000 <== mismatch
 148in9 (VINR1)  :  alarms: 0x004000 beep_mask: 0x004000
 149temp1        :  alarms: 0x000010 beep_mask: 0x000010
 150temp2        :  alarms: 0x000020 beep_mask: 0x000020
 151temp3        :  alarms: 0x002000 beep_mask: 0x000002 <== mismatch
 152fan1         :  alarms: 0x000040 beep_mask: 0x000040
 153fan2         :  alarms: 0x000080 beep_mask: 0x000080
 154fan3         :  alarms: 0x000800 beep_mask: 0x000800
 155fan4         :  alarms: 0x200000 beep_mask: 0x200000
 156fan5         :  alarms: 0x400000 beep_mask: 0x400000
 157tart1        :  alarms: 0x010000 beep_mask: 0x040000 <== mismatch
 158tart2        :  alarms: 0x020000 beep_mask: 0x080000 <== mismatch
 159tart3        :  alarms: 0x040000 beep_mask: 0x100000 <== mismatch
 160case_open    :  alarms: 0x001000 beep_mask: 0x001000
 161global_enable:  alarms: -------- beep_mask: 0x800000 (modified via beep_enable)
 162
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