Updated driver for LM85

Mark Studebaker mds at paradyne.com
Tue Feb 18 19:35:13 CET 2003


you can work with me.
I didn't realize (or forgot) you were working on a driver.
Coincidentally, Margit (email above) is also working on a driver 
and is preparing to submit it to us.

Would you two please get together and compare drivers and
either combine them or decide which one is best,
(and conforming to our guidelines in doc/developers/new-drivers)
then let me know and I can get that one checked in.

thanks
mds



Philip Pokorny wrote:
> 
> I've respun my lm85/adm1027/adt7463 driver for the 2.7.0 release.
> 
> We've been using it here at Penguin Computing on the Intel S845WD1-E
> motherboard for several months.  I added support for the adm1027 when I found
> that chip on a Tyan motherboard we use.  The ADT7463 was added from specs when
> Analog Devices Technical support told me that it fixes a bug in the ADM1027
> related to the temperature offset registers.  (Documentation says .25 degC
> resolution, actual resolution is 1 degC)
> 
> There is complete support in sensors and in the library for all the features.
> 
> I've corresponded with David Barrington who put the original detection code
> into sensors-detect, but had not completed a driver.
> 
> I'm attaching the documentation file.
> 
> What else should I do to get this commited to CVS?
> 
> Thanks,
> :v)
> 
>   --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> Kernel driver `lm85.o'
> ======================
> 
> Status: Complete and somewhat tested
> 
> Supported chips:
>   * National Semiconductors LM85 (B and C versions)
>     Prefix `lm85'
>     Addresses scanned: I2C 0x2c, 0x2d, 0x2e
>   * Analog Devices ADM1027
>     Prefix `adm1027'
>     Addresses scanned: I2C 0x2c, 0x2d, 0x2e
>   * Analog Devices ADT7463
>     Prefix 'adt7463'
>     Addresses scanned: I2C 0x2c, 0x2d, 0x2e
> 
> Authors:
>       Philip Pokorny <ppokorny at penguincomputing.com>
>       Frodo Looijaard <frodol at dds.nl>
>       Richard Barrington <rich_b_nz at clear.net.nz>
> 
> Module Parameters
> -----------------
> 
> * init: integer
>   Bypass chip initialization if set to 0.  Useful if the BIOS has setup the
>   chip already or if you're using the "force_" options.
> * force: short array (min = 1, max = 48)
>   List of adapter,address pairs to boldly assume to be present
> * force_lm85b: short array (min = 1, max = 48)
>   List of adapter,address pairs which are unquestionably assumed to contain
>   a `lm85-B' chip
> * force_lm85c: short array (min = 1, max = 48)
>   List of adapter,address pairs which are unquestionably assumed to contain
>   a `lm85-B' chip
> * force_adm1027: short array (min = 1, max = 48)
>   List of adapter,address pairs which are unquestionably assumed to contain
>   a `adm1027' chip
> * force_adt7463: short array (min = 1, max = 48)
>   List of adapter,address pairs which are unquestionably assumed to contain
>   a `adt7463' 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 LM85
> and compatible chips including the Analog Devices ADM1027.
> 
> The LM85 uses the 2-wire interface compatible with the SMBUS 2.0
> specification.  Using an analog to digital converter it measures three
> (3) temperatures and five (5) voltages.  It has four (4) 16-bit
> counters for measuring fan speed.  Five (5) digital inputs are
> provided for sampling the VID signals from the processor to the VRM.
> Lastly, there are three (3) PWM outputs that can be used to control
> fan speed.
> 
> The voltage inputs have internal scaling resistors so that the
> following voltage can be measured without external resistors:
> 
>    2.5V, 3.3V, 5V, 12V, and CPU core voltage (2.25V)
> 
> The temperatures measured are one internal diode, and two remote
> diodes.  Remote 1 is generally the CPU temperature.  These inputs are
> designed to measure a thermal diode like the one in a Pentium 4
> processor in a socket 423 or socket 478 package.  They can also
> measure temperature using a transistor like the 2N3904.
> 
> A sophisticated control system for the PWM outputs is designed into
> the LM85 that allows fan speed to be adjusted automatically based on
> any of the three temperature sensors.  Each PWM output is individually
> adjustable and programmable.  Once configured, the LM85 will adjust
> the PWM outputs in response to the measured temperatures without
> further host intervention.  This feature can also be disabled for
> manual control of the PWM's.
> 
> Each of the measured inputs (voltage, temperature, fan speed) has
> corresponding high/low limit values.  The LM85 will signal an ALARM if
> any measured value exceeds either limit.
> 
> The LM85 samples all inputs continuously.  The lm85 driver will not
> read the lm85 more often than once a second.  Further, configuration
> data is only read once each 5 minutes.  There is twice as much config
> data as measurements, so this would seem to be a worthwhile
> optimization.
> 
> Special Features
> 
> The LM85 has four fan speed monitoring modes.  The ADM1027 has only
> two.  Both have special circuitry to compensate for PWM interactions
> with the TACH signal from the fans.  The ADM1027 can be configured to
> measure the speed of a two wire fan, but the input conditioning
> circuitry is different for 3-wire and 2-wire mode.  For this reason,
> the 2-wire fan modes are not exposed to user control.  The BIOS should
> initialize them to the correct mode.  If you've designed your own
> ADM1027, you'll have to modify the init_client function and add an
> insmod parameter to set this up.
> 
> To smooth the response of fans to changes in temperature, the LM85 has
> an optional filter for smoothing temperatures.  The ADM1027 has the
> same config option but uses it to rate limit the changes to fan speed
> instead.  In libsensors, we associate the smoothing feature with a
> zone in the LM85 and with a PWM in the ADM1027.
> 
> The ADM1027 has a 10-bit ADC and can therefore measure temperatures
> with .25 degC resolution.  The ADM1027 also provides an offset
> to the temperature readings that is automatically applied during
> measurement.  This offset can be used to zero out any errors due to
> traces and placement.  The documentation says that the offset is in
> 0.25 degC steps, but in initial testing it was 1 degC steps.  The
> driver currently reports 0.25 degC steps in accordance with the
> datasheet.
> 
> See the LM85 and ADM1027 datasheets for more information.  There is
> application note from National (AN-1260) with some additional
> information about the LM85.  The Analog Devices datasheet is very
> detailed and describes a procedure for determining an optimal
> configuration for the automatic PWM control.
> 
> Hardware Configurations
> -----------------------
> 
> The LM85 can be jumpered for 3 different SMBus addresses.  There are
> no other hardware configuration options.
> 
> The lm85 driver detects both LM85B and LM85C revisions of the chip.
> See the datasheet for a complete description of the differences.
> Other than identifying the chip, the driver behaves no differently
> with regard to these two chips.  The LM85C is recommended for new
> designs.
> 
> The lm85 driver also detects the ADM1027 chip.  There are several
> features which are implemented differently on this chip.  In
> particular, the tach_mode, spinup_ctl, and the fan smoothing are
> slightly different.  See comments below.
> 
> Configuration Notes
> -------------------
> 
> The voltage, temperature and fan inputs are available in libsensors
> and the sensors executable.  In addition, the automatic control of the
> PWM outputs can also be configured via sensors.conf.  This
> configuration is described below:
> 
> * Temperatures and Zones
> 
> Each temperature sensor is associated with a Zone.  There are three
> sensors and therefore three zones.  Each zone has the following
> temperature configuration points:
> 
>     Limit temp    -- Temperature at which the fan will turn on
>                      [ absolute deg C from 0.0 to 127.0 ]
>                      [ sensors.conf:   zone#_limit ]
>     Hysteresis    -- Degrees below the limit that fan will remain
>                      on before turning off.
>                      [ relative C from 0.0 to -15.0 ]
>                      [ sensors.conf:   zone#_hyst ]
>     Range         -- Degrees above the limit over which the fan
>                      PWM will be adjusted (from PWM_MIN to 100%)
>                      [ relative deg C from 2.0 to 80.0 ]
>                      [ sensors.conf:   zone#_range ]
>     Critical temp -- Temperature above which other fans will be
>                      forced to 100% PWM
>                      [ absolute deg C from 0.0 to 127.0 ]
>                      [ sensors.conf:   zone#_critical ]
> 
> ** Temperature Range for a Zone
> 
> The RANGE value for a given zone can have one of 16 different values
> in an approximately logrithmic spacing:
> Selecting a RANGE not in this list will cause the next larger range to
> be used.
> 
>     Temperature ranges:    2.0, 2.5, 3.3, 4.0, 5.0, 6.6, 8.0, 10.0,
>       (in deg C)           13.3, 16.0, 20.0, 26.6, 32.0, 40.0, 53.3,
>                            80.0
> 
> * Temperature Smoothing or Acoustic Enhancement
> 
> The LM85 and ADM1027 use this value in different ways.  In the LM85
> it's used to filter the temperature input of a zone.  In this way, it
> affects all PWM's controlled by that zone temperature.  In the
> ADM1027, it limits the rate of change in fan speed.  Thus it is part
> of the PWM control algorithm.
> 
>     Smooth filter -- Optional filter constant to smooth the system
>                      response to temperature spikes.  It either
>                      filters the measured temperatures or limits the
>                      rate of change of fan speed.  This improves
>                      the system by limiting rapid changes in fan
>                      speed.
>                      [ seconds from 0.8 to 35.0 or 0.0 for OFF ]
>                      [ sensors.conf:   zone#_smooth or pwm#_smooth ]
> 
> The smoothing can be disabled, or enabled and set to one of the values
> listed below.  Selecting a filter time constant not on this list will
> cause the next smaller value to be used.  Setting the time constant to
> 0 will disable the filtering.
> 
>     Filter time constant:  35.0, 17.6, 11.8, 7.0, 4.4, 3.0, 1.6, 0.8
>       (in seconds)
> 
> * PWM Control
> 
> There are three PWM outputs.  The LM85 datasheet suggests that the
> PWM3 output control both FAN3 and FAN4.  Each PWM can be individually
> configured and assigned to a zone for it's control value.  Each PWM can be
> configured individually according to the following options.
> 
>     Spinup time   -- When turning on a fan that was off, the PWM will
>                      temporarily be set to 100% for this length of
>                      time to insure the fan starts spinning.
>                      [ seconds from 0.0 to 4.0 ]
>                      [ sensors.conf:  pwm#_spinup ]
>     Minimum PWM   -- This is the PWM value at the limit temp of the
>                      referenced zone.
>                      [ percent from 0.0 to 100.0 ]
>                      [ sensors.conf:  pwm#_min ]
>     Frequency     -- This is the base frequency of the PWM output.
>                      [ Hz from 10.0 to 98.0 ]
>                      [ sensors.conf:  pwm#_freq ]
>     Min/Off flag  -- This flag determines if the PWM will be off or
>                      "min PWM" below the limit temperature.
>                      [ 0.0 means PWM off (0%) below limit ]
>                      [ sensors.conf:  pwm#_min_ctl ]
>     Invert flag   -- This flag causes the PWM output to be inverted.
>                      If inverted, a PWM setting of 0 will be full on
>                      and 100 will be off.
>                      [ 0.0 means PWM is "normal" ]
>                      [ sensors.conf:  pwm#_invert ]
> 
> ** Spinup Time
> 
> Spinup time can be one of eight (8) values.  Selecting a spinup time
> not on this list will result in the next larger spinup time being
> selected.  Note, the value 0.2 actually results in a setting of 0.250
> seconds.
> 
>     Spinup Time     0.0, 0.1, 0.2, 0.4, 0.7, 1.0, 2.0, 4.0
>       (in seconds)
> 
> ** PWM Frequency
> 
> The base frequency of the PWM can be controlled.  The frequency can be
> set to one of the following 8 values.  Setting the frequency to a
> value not on this list, will result in the next higher frequency being
> selected.  The actual device frequency may vary slightly from this
> specification as designed by the manufacturer.  Consult the datasheet
> for more details.
> 
>     PWM Frequency   10.0, 15.0, 23.0, 30.0, 38.0, 47.0, 62.0, 98.0
>       (in Hz)
> 
> ** Min/Off Flag
> 
> Below the temperature "Limit - Hysteresis" from the controlling zone,
> the PWM can turn off (set to 0) or it can stay at the minimum PWM
> value.  Setting this flag to 1 will cause the PWM value to be the
> "Minimum PWM" value below this limit.  Setting it to 0 will set the
> PWM to 0 (off) below that limit.
> 
> ** Invert Flag
> 
> The PWM output can be inverted.  This may be useful if the fan power
> circuitry is inverted. (A low output turns on power and a high output
> turns off power to the fan).  Alternatively, if a slower fan speed is
> needed for higher temperatures, this could be set.
> 
> Setting this flag to 1 will invert the PWM output.  A value of 0
> does not invert the PWM output.
> 
> * PWM Controlling Zone selection
> 
> PWM's can be controlled by zones according to the following
> configuration choices:
> 
>    Value     Meaning
>   ------  ------------------------------------------------
>       1    Controlled by Zone 1
>       2    Controlled by Zone 2
>       3    Controlled by Zone 3
>      23    Controlled by higher temp of Zone 2 or 3
>     123    Controlled by highest temp of Zone 1, 2 or 3
>       0    PWM alwasy 0%  (off)
>      -1    PWM always 100%  (full on)
>      -2    Manual control (write to 'pwm#' to set)
> 
> These are specified in sensors.conf using 'pwm#_zone'
> 
> * /proc Interface
> 
> These values can also be set using the /proc interface.  The following
> files contain the above settings in the order listed below:
> 
>     Name         Values
>    ---------- ----------------------------------------------------
>     zone#      Limit, Hysteresis, Range, Critical
>     pwm#_cfg   Spinup, PWM at low limit, Frequency, Min/Off, Invert
>     pwm#_zone  Control Zone choice
>     smooth#    Filtering
> 
> The National LM85's have two vendor specific configuration
> features.  Tach. mode and Spinup Control.  For more details on these,
> see the LM85 datasheet or Application Note AN-1260.
> 
>     Name           Values
>    ------------ --------------------------------------------------
>     tach_mode    For best fan speed measurement when PWM's are in use,
>                  the Tach Mode should be set to 2 for all three (Fan's
>                  3 and 4 share a config setting) config values.  If
>                  PWM's are not in use or not wired to control fan
>                  speed, mode 0 or 1 may be better.
>                  [ sensors.conf:   fan#_tach_mode ]
>     spinup_ctl   Setting spinup_ctl to 1 will modify the fan spinup
>                  algorithm.  Instead of setting the PWM to 100% for
>                  the configured period of time, it will be set to 100%
>                  until the measured RPM is greater than the RPM limit
>                  register or the time period elapses.
>                  [ sensors.conf:   pwm#_spinup_ctl ]
> 
> The Analog Devices ADM1027 has several vendor specific enhancements.
> The number of pulses-per-rev of the fans can be set, Tach monitoring
> can be optimized for PWM operation, and an offset can be applied to
> the temperatures to compensate for systemic errors in the
> measurements.
> 
>     Name           Values
>    ------------ --------------------------------------------------
>     tach_mode    For best fan speed measurement when PWM's are in use,
>                  the Tach Mode should be set to 0.  If PWM's are not
>                  in use or not wired to control fan speed, a mode of 1
>                  can be selected.  This will also increase the rate
>                  of fan speed measurement from 1 per second to 4 per
>                  second.
>                  [ sensors.conf:   fan#_tach_mode ]
>     fan_ppr      You can set the pulses per rev to 1, 2, 3 or 4 so
>                  that fan speeds don't have to be scaled.
>                  [ sensors.conf:   fan#_ppr ]
>     temp#_offset This is the value to be added or subtracted from the
>                  measured temperature before reporting it.  This also
>                  affects the PWM control algorithms.
>                  [ sensors.conf:   temp#_offset ]
> 
> * Sample sensors.conf Config File
> 
> Here is a sample LM85 chip config for sensors.conf
> 
> --------- cut here ---------
> chip "lm85c-*" "adm1027-*" "lm85-*" "lm85b-*"
> 
> # Voltage inputs
>    label in0   "V1.5"      # AGP on Intel S845WD1-E
>    label in1   "VCore"
>    label in2   "V3.3"
>    label in3   "V5"
>    label in4   "V12"
> 
> # Temperature inputs
>    label temp1  "CPU"
>    label temp2  "Board"
>    label temp3  "Remote"
> 
> # Fan inputs
>    label fan1   "CPU_Fan"
>    label fan2   "Fan2"
>    label fan3   "Fan3"
>    label fan4   "Fan4"
> 
> # PWM Outputs
>    label pwm1   "Fan2"
>    label pwm2   "Fan3"
>    label pwm3   "Fan4"
> 
> # Scale voltages correctly  NOTE: This corresponds to the
> #    internal scaling of the chip.  This should not need
> #    to be adjusted
>    compute in0  @ * 2.5,   @ / 2.5
>    compute in1  @ * 2.25,  @ / 2.25
>    compute in2  @ * 3.3,   @ / 3.3
>    compute in3  @ * 5.0,   @ / 5.0
>    compute in4  @ * 12.0,  @ / 12.0
> 
> # Adjust fans speeds for actual pulses per rev
>    compute fan1  @ * 2,  @ / 2    # 1 pulse per rev
> #  set fan1_ppr  1                # ADM1027 only
>    compute fan2  @ / 2,  @ * 2    # 4 pulse per rev
> #  set fan2_ppr  4                # ADM1027 only
> 
> # Set VRM version
>    set vrm  9.1   # Pentium 4
> 
> # Set voltage limits
>    set in0_min  1.5 * 0.95
>    set in0_max  1.5 * 1.05
>    set in1_min  vid * 0.95
>    set in1_max  vid * 1.05
>    set in2_min  3.3 * 0.95
>    set in2_max  3.3 * 1.05
>    set in3_min  5.0 * 0.95
>    set in4_max  5.0 * 1.05
>    set in4_min   12 * 0.95
>    set in3_max   12 * 1.05
> 
> # Set Fan limits
>    set fan1_min  3000
>    set fan2_min  3000
>    set fan3_min  3000
>    set fan4_min  3000



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