cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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w83791d.rst (6863B)


      1Kernel driver w83791d
      2=====================
      3
      4Supported chips:
      5
      6  * Winbond W83791D
      7
      8    Prefix: 'w83791d'
      9
     10    Addresses scanned: I2C 0x2c - 0x2f
     11
     12    Datasheet: http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83791D_W83791Gb.pdf
     13
     14Author: Charles Spirakis <bezaur@gmail.com>
     15
     16This driver was derived from the w83781d.c and w83792d.c source files.
     17
     18Credits:
     19
     20  w83781d.c:
     21
     22    - Frodo Looijaard <frodol@dds.nl>,
     23    - Philip Edelbrock <phil@netroedge.com>,
     24    - Mark Studebaker <mdsxyz123@yahoo.com>
     25
     26  w83792d.c:
     27
     28    - Shane Huang (Winbond),
     29    - Rudolf Marek <r.marek@assembler.cz>
     30
     31Additional contributors:
     32
     33    - Sven Anders <anders@anduras.de>
     34    - Marc Hulsman <m.hulsman@tudelft.nl>
     35
     36Module Parameters
     37-----------------
     38
     39* init boolean
     40    (default 0)
     41
     42    Use 'init=1' to have the driver do extra software initializations.
     43    The default behavior is to do the minimum initialization possible
     44    and depend on the BIOS to properly setup the chip. If you know you
     45    have a w83791d and you're having problems, try init=1 before trying
     46    reset=1.
     47
     48* reset boolean
     49    (default 0)
     50
     51    Use 'reset=1' to reset the chip (via index 0x40, bit 7). The default
     52    behavior is no chip reset to preserve BIOS settings.
     53
     54* force_subclients=bus,caddr,saddr,saddr
     55    This is used to force the i2c addresses for subclients of
     56    a certain chip. Example usage is `force_subclients=0,0x2f,0x4a,0x4b`
     57    to force the subclients of chip 0x2f on bus 0 to i2c addresses
     58    0x4a and 0x4b.
     59
     60
     61Description
     62-----------
     63
     64This driver implements support for the Winbond W83791D chip. The W83791G
     65chip appears to be the same as the W83791D but is lead free.
     66
     67Detection of the chip can sometimes be foiled because it can be in an
     68internal state that allows no clean access (Bank with ID register is not
     69currently selected). If you know the address of the chip, use a 'force'
     70parameter; this will put it into a more well-behaved state first.
     71
     72The driver implements three temperature sensors, ten voltage sensors,
     73five fan rotation speed sensors and manual PWM control of each fan.
     74
     75Temperatures are measured in degrees Celsius and measurement resolution is 1
     76degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when
     77the temperature gets higher than the Overtemperature Shutdown value; it stays
     78on until the temperature falls below the Hysteresis value.
     79
     80Voltage sensors (also known as IN sensors) report their values in millivolts.
     81An alarm is triggered if the voltage has crossed a programmable minimum
     82or maximum limit.
     83
     84Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
     85triggered if the rotation speed has dropped below a programmable limit. Fan
     86readings can be divided by a programmable divider (1, 2, 4, 8, 16,
     8732, 64 or 128 for all fans) to give the readings more range or accuracy.
     88
     89Each fan controlled is controlled by PWM. The PWM duty cycle can be read and
     90set for each fan separately. Valid values range from 0 (stop) to 255 (full).
     91PWM 1-3 support Thermal Cruise mode, in which the PWMs are automatically
     92regulated to keep respectively temp 1-3 at a certain target temperature.
     93See below for the description of the sysfs-interface.
     94
     95The w83791d has a global bit used to enable beeping from the speaker when an
     96alarm is triggered as well as a bitmask to enable or disable the beep for
     97specific alarms. You need both the global beep enable bit and the
     98corresponding beep bit to be on for a triggered alarm to sound a beep.
     99
    100The sysfs interface to the global enable is via the sysfs beep_enable file.
    101This file is used for both legacy and new code.
    102
    103The sysfs interface to the beep bitmask has migrated from the original legacy
    104method of a single sysfs beep_mask file to a newer method using multiple
    105`*_beep` files as described in `Documentation/hwmon/sysfs-interface.rst`.
    106
    107A similar change has occurred for the bitmap corresponding to the alarms. The
    108original legacy method used a single sysfs alarms file containing a bitmap
    109of triggered alarms. The newer method uses multiple sysfs `*_alarm` files
    110(again following the pattern described in sysfs-interface).
    111
    112Since both methods read and write the underlying hardware, they can be used
    113interchangeably and changes in one will automatically be reflected by
    114the other. If you use the legacy bitmask method, your user-space code is
    115responsible for handling the fact that the alarms and beep_mask bitmaps
    116are not the same (see the table below).
    117
    118NOTE: All new code should be written to use the newer sysfs-interface
    119specification as that avoids bitmap problems and is the preferred interface
    120going forward.
    121
    122The driver reads the hardware chip values at most once every three seconds.
    123User mode code requesting values more often will receive cached values.
    124
    125/sys files
    126----------
    127The sysfs-interface is documented in the 'sysfs-interface' file. Only
    128chip-specific options are documented here.
    129
    130======================= =======================================================
    131pwm[1-3]_enable		this file controls mode of fan/temperature control for
    132			fan 1-3. Fan/PWM 4-5 only support manual mode.
    133
    134			    * 1 Manual mode
    135			    * 2 Thermal Cruise mode
    136			    * 3 Fan Speed Cruise mode (no further support)
    137
    138temp[1-3]_target	defines the target temperature for Thermal Cruise mode.
    139			Unit: millidegree Celsius
    140			RW
    141
    142temp[1-3]_tolerance	temperature tolerance for Thermal Cruise mode.
    143			Specifies an interval around the target temperature
    144			in which the fan speed is not changed.
    145			Unit: millidegree Celsius
    146			RW
    147======================= =======================================================
    148
    149Alarms bitmap vs. beep_mask bitmask
    150-----------------------------------
    151
    152For legacy code using the alarms and beep_mask files:
    153
    154=============  ========  ========= ==========================
    155Signal         Alarms    beep_mask Obs
    156=============  ========  ========= ==========================
    157in0 (VCORE)    0x000001  0x000001
    158in1 (VINR0)    0x000002  0x002000  <== mismatch
    159in2 (+3.3VIN)  0x000004  0x000004
    160in3 (5VDD)     0x000008  0x000008
    161in4 (+12VIN)   0x000100  0x000100
    162in5 (-12VIN)   0x000200  0x000200
    163in6 (-5VIN)    0x000400  0x000400
    164in7 (VSB)      0x080000  0x010000  <== mismatch
    165in8 (VBAT)     0x100000  0x020000  <== mismatch
    166in9 (VINR1)    0x004000  0x004000
    167temp1          0x000010  0x000010
    168temp2          0x000020  0x000020
    169temp3          0x002000  0x000002  <== mismatch
    170fan1           0x000040  0x000040
    171fan2           0x000080  0x000080
    172fan3           0x000800  0x000800
    173fan4           0x200000  0x200000
    174fan5           0x400000  0x400000
    175tart1          0x010000  0x040000  <== mismatch
    176tart2          0x020000  0x080000  <== mismatch
    177tart3          0x040000  0x100000  <== mismatch
    178case_open      0x001000  0x001000
    179global_enable  -         0x800000  (modified via beep_enable)
    180=============  ========  ========= ==========================