287 строки
11 KiB
ReStructuredText
287 строки
11 KiB
ReStructuredText
Kernel driver lm85
|
|
==================
|
|
|
|
Supported chips:
|
|
|
|
* National Semiconductor LM85 (B and C versions)
|
|
|
|
Prefix: 'lm85b' or 'lm85c'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: http://www.national.com/pf/LM/LM85.html
|
|
|
|
* Texas Instruments LM96000
|
|
|
|
Prefix: 'lm9600'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: https://www.ti.com/lit/ds/symlink/lm96000.pdf
|
|
|
|
* Analog Devices ADM1027
|
|
|
|
Prefix: 'adm1027'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: https://www.onsemi.com/PowerSolutions/product.do?id=ADM1027
|
|
|
|
* Analog Devices ADT7463
|
|
|
|
Prefix: 'adt7463'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: https://www.onsemi.com/PowerSolutions/product.do?id=ADT7463
|
|
|
|
* Analog Devices ADT7468
|
|
|
|
Prefix: 'adt7468'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: https://www.onsemi.com/PowerSolutions/product.do?id=ADT7468
|
|
|
|
* SMSC EMC6D100, SMSC EMC6D101
|
|
|
|
Prefix: 'emc6d100'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: http://www.smsc.com/media/Downloads_Public/discontinued/6d100.pdf
|
|
|
|
* SMSC EMC6D102
|
|
|
|
Prefix: 'emc6d102'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: http://www.smsc.com/main/catalog/emc6d102.html
|
|
|
|
* SMSC EMC6D103
|
|
|
|
Prefix: 'emc6d103'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: http://www.smsc.com/main/catalog/emc6d103.html
|
|
|
|
* SMSC EMC6D103S
|
|
|
|
Prefix: 'emc6d103s'
|
|
|
|
Addresses scanned: I2C 0x2c, 0x2d, 0x2e
|
|
|
|
Datasheet: http://www.smsc.com/main/catalog/emc6d103s.html
|
|
|
|
Authors:
|
|
- Philip Pokorny <ppokorny@penguincomputing.com>,
|
|
- Frodo Looijaard <frodol@dds.nl>,
|
|
- Richard Barrington <rich_b_nz@clear.net.nz>,
|
|
- Margit Schubert-While <margitsw@t-online.de>,
|
|
- Justin Thiessen <jthiessen@penguincomputing.com>
|
|
|
|
Description
|
|
-----------
|
|
|
|
This driver implements support for the National Semiconductor LM85 and
|
|
compatible chips including the Analog Devices ADM1027, ADT7463, ADT7468 and
|
|
SMSC EMC6D10x chips family.
|
|
|
|
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 registers 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.
|
|
|
|
The ADM1027, ADT7463 and ADT7468 have a 10-bit ADC and can therefore
|
|
measure temperatures with 0.25 degC resolution. They also provide 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 of the ADM1027 it was 1.00 degC steps. Analog
|
|
Devices has confirmed this "bug". The ADT7463 is reported to work as
|
|
described in the documentation. The current lm85 driver does not show the
|
|
offset register.
|
|
|
|
The ADT7468 has a high-frequency PWM mode, where all PWM outputs are
|
|
driven by a 22.5 kHz clock. This is a global mode, not per-PWM output,
|
|
which means that setting any PWM frequency above 11.3 kHz will switch
|
|
all 3 PWM outputs to a 22.5 kHz frequency. Conversely, setting any PWM
|
|
frequency below 11.3 kHz will switch all 3 PWM outputs to a frequency
|
|
between 10 and 100 Hz, which can then be tuned separately.
|
|
|
|
See the vendor 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.
|
|
|
|
The SMSC EMC6D100 & EMC6D101 monitor external voltages, temperatures, and
|
|
fan speeds. They use this monitoring capability to alert the system to out
|
|
of limit conditions and can automatically control the speeds of multiple
|
|
fans in a PC or embedded system. The EMC6D101, available in a 24-pin SSOP
|
|
package, and the EMC6D100, available in a 28-pin SSOP package, are designed
|
|
to be register compatible. The EMC6D100 offers all the features of the
|
|
EMC6D101 plus additional voltage monitoring and system control features.
|
|
Unfortunately it is not possible to distinguish between the package
|
|
versions on register level so these additional voltage inputs may read
|
|
zero. EMC6D102 and EMC6D103 feature additional ADC bits thus extending precision
|
|
of voltage and temperature channels.
|
|
|
|
SMSC EMC6D103S is similar to EMC6D103, but does not support pwm#_auto_pwm_minctl
|
|
and temp#_auto_temp_off.
|
|
|
|
The LM96000 supports additional high frequency PWM modes (22.5 kHz, 24 kHz,
|
|
25.7 kHz, 27.7 kHz and 30 kHz), which can be configured on a per-PWM basis.
|
|
|
|
Hardware Configurations
|
|
-----------------------
|
|
|
|
The LM85 can be jumpered for 3 different SMBus addresses. There are
|
|
no other hardware configuration options for the LM85.
|
|
|
|
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 LM85B is recommended for new designs.
|
|
|
|
The ADM1027, ADT7463 and ADT7468 chips have an optional SMBALERT output
|
|
that can be used to signal the chipset in case a limit is exceeded or the
|
|
temperature sensors fail. Individual sensor interrupts can be masked so
|
|
they won't trigger SMBALERT. The SMBALERT output if configured replaces one
|
|
of the other functions (PWM2 or IN0). This functionality is not implemented
|
|
in current driver.
|
|
|
|
The ADT7463 and ADT7468 also have an optional THERM output/input which can
|
|
be connected to the processor PROC_HOT output. If available, the autofan
|
|
control dynamic Tmin feature can be enabled to keep the system temperature
|
|
within spec (just?!) with the least possible fan noise.
|
|
|
|
Configuration Notes
|
|
-------------------
|
|
|
|
Besides standard interfaces driver adds following:
|
|
|
|
* Temperatures and Zones
|
|
|
|
Each temperature sensor is associated with a Zone. There are three
|
|
sensors and therefore three zones (# 1, 2 and 3). Each zone has the following
|
|
temperature configuration points:
|
|
|
|
* temp#_auto_temp_off
|
|
- temperature below which fans should be off or spinning very low.
|
|
* temp#_auto_temp_min
|
|
- temperature over which fans start to spin.
|
|
* temp#_auto_temp_max
|
|
- temperature when fans spin at full speed.
|
|
* temp#_auto_temp_crit
|
|
- temperature when all fans will run full speed.
|
|
|
|
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 its control value. Each PWM can be
|
|
configured individually according to the following options.
|
|
|
|
* pwm#_auto_pwm_min
|
|
- this specifies the PWM value for temp#_auto_temp_off
|
|
temperature. (PWM value from 0 to 255)
|
|
|
|
* pwm#_auto_pwm_minctl
|
|
- this flags selects for temp#_auto_temp_off temperature
|
|
the behaviour of fans. Write 1 to let fans spinning at
|
|
pwm#_auto_pwm_min or write 0 to let them off.
|
|
|
|
.. note::
|
|
|
|
It has been reported that there is a bug in the LM85 that causes
|
|
the flag to be associated with the zones not the PWMs. This
|
|
contradicts all the published documentation. Setting pwm#_min_ctl
|
|
in this case actually affects all PWMs controlled by zone '#'.
|
|
|
|
PWM Controlling Zone selection
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
* pwm#_auto_channels
|
|
- controls zone that is associated with PWM
|
|
|
|
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 always 0% (off)
|
|
-1 PWM always 100% (full on)
|
|
-2 Manual control (write to 'pwm#' to set)
|
|
========== =============================================
|
|
|
|
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. These features
|
|
are not currently supported by the lm85 driver.
|
|
|
|
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. These features are not currently supported by the lm85
|
|
driver.
|
|
|
|
In addition to the ADM1027 features, the ADT7463 and ADT7468 also have
|
|
Tmin control and THERM asserted counts. Automatic Tmin control acts to
|
|
adjust the Tmin value to maintain the measured temperature sensor at a
|
|
specified temperature. There isn't much documentation on this feature in
|
|
the ADT7463 data sheet. This is not supported by current driver.
|