mirror of
https://github.com/adulau/aha.git
synced 2024-12-27 19:26:25 +00:00
hwmon: (adt7475) New documentation
New documentation for the adt7475 driver, based on the adt7473 driver documentation. It is IMHO much more useful that the previous documentation which was essentially redundant with sysfs-interface. Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: "Mark M. Hoffman" <mhoffman@lightlink.com> Cc: Hans de Goede <hdegoede@redhat.com> Cc: Jordan Crouse <jordan@cosmicpenguin.net> Cc: "Darrick J. Wong" <djwong@us.ibm.com>
This commit is contained in:
Jean Delvare
parent
b180d05084
commit
f890c6a3b6
1 changed files with 64 additions and 68 deletions
|
|
@ -1,87 +1,83 @@
|
|||
This describes the interface for the ADT7475 driver:
|
||||
Kernel driver adt7475
|
||||
=====================
|
||||
|
||||
(there are 4 fans, numbered fan1 to fan4):
|
||||
Supported chips:
|
||||
* Analog Devices ADT7473
|
||||
Prefix: 'adt7473'
|
||||
Addresses scanned: I2C 0x2C, 0x2D, 0x2E
|
||||
Datasheet: Publicly available at the On Semiconductors website
|
||||
* Analog Devices ADT7475
|
||||
Prefix: 'adt7475'
|
||||
Addresses scanned: I2C 0x2E
|
||||
Datasheet: Publicly available at the On Semiconductors website
|
||||
|
||||
fanX_input Read the current speed of the fan (in RPMs)
|
||||
fanX_min Read/write the minimum speed of the fan. Dropping
|
||||
below this sets an alarm.
|
||||
Authors:
|
||||
Jordan Crouse
|
||||
Hans de Goede
|
||||
Darrick J. Wong (documentation)
|
||||
|
||||
(there are three PWMs, numbered pwm1 to pwm3):
|
||||
|
||||
pwmX Read/write the current duty cycle of the PWM. Writes
|
||||
only have effect when auto mode is turned off (see
|
||||
below). Range is 0 - 255.
|
||||
Description
|
||||
-----------
|
||||
|
||||
pwmX_enable Fan speed control method:
|
||||
This driver implements support for the Analog Devices ADT7473 and ADT7475
|
||||
chip family. Both chips differ only in minor details. They will be
|
||||
collectively designed by the name "ADT747x" in the rest of this document.
|
||||
|
||||
0 - No control (fan at full speed)
|
||||
1 - Manual fan speed control (using pwm[1-*])
|
||||
2 - Automatic fan speed control
|
||||
The ADT747x uses the 2-wire interface compatible with the SMBus 2.0
|
||||
specification. Using an analog to digital converter it measures three (3)
|
||||
temperatures and two (2) voltages. It has four (4) 16-bit counters for
|
||||
measuring fan speed. There are three (3) PWM outputs that can be used
|
||||
to control fan speed.
|
||||
|
||||
pwmX_auto_channels_temp Select which channels affect this PWM
|
||||
A sophisticated control system for the PWM outputs is designed into the
|
||||
ADT747x 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 ADT747x 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.
|
||||
|
||||
1 - TEMP1 controls PWM
|
||||
2 - TEMP2 controls PWM
|
||||
4 - TEMP3 controls PWM
|
||||
6 - TEMP2 and TEMP3 control PWM
|
||||
7 - All three inputs control PWM
|
||||
Each of the measured inputs (voltage, temperature, fan speed) has
|
||||
corresponding high/low limit values. The ADT747x will signal an ALARM if
|
||||
any measured value exceeds either limit.
|
||||
|
||||
pwmX_freq Read/write the PWM frequency in Hz. The number
|
||||
should be one of the following:
|
||||
The ADT747x samples all inputs continuously. The driver will not read
|
||||
the registers more often than once every other second. Further,
|
||||
configuration data is only read once per minute.
|
||||
|
||||
11 Hz
|
||||
14 Hz
|
||||
22 Hz
|
||||
29 Hz
|
||||
35 Hz
|
||||
44 Hz
|
||||
58 Hz
|
||||
88 Hz
|
||||
Special Features
|
||||
----------------
|
||||
|
||||
pwmX_auto_point1_pwm Read/write the minimum PWM duty cycle in automatic mode
|
||||
The ADT747x has a 10-bit ADC and can therefore measure temperatures
|
||||
with a resolution of 0.25 degree Celsius. Temperature readings can be
|
||||
configured either for two's complement format or "Offset 64" format,
|
||||
wherein 64 is subtracted from the raw value to get the temperature value.
|
||||
|
||||
pwmX_auto_point2_pwm Read/write the maximum PWM duty cycle in automatic mode
|
||||
The datasheet is very detailed and describes a procedure for determining
|
||||
an optimal configuration for the automatic PWM control.
|
||||
|
||||
(there are three temperature settings numbered temp1 to temp3):
|
||||
Fan Speed Control
|
||||
-----------------
|
||||
|
||||
tempX_input Read the current temperature. The value is in milli
|
||||
degrees of Celsius.
|
||||
The driver exposes two trip points per PWM channel.
|
||||
|
||||
tempX_max Read/write the upper temperature limit - exceeding this
|
||||
will cause an alarm.
|
||||
point1: Set the PWM speed at the lower temperature bound
|
||||
point2: Set the PWM speed at the higher temperature bound
|
||||
|
||||
tempX_min Read/write the lower temperature limit - exceeding this
|
||||
will cause an alarm.
|
||||
The ADT747x will scale the PWM linearly between the lower and higher PWM
|
||||
speed when the temperature is between the two temperature boundaries.
|
||||
Temperature boundaries are associated to temperature channels rather than
|
||||
PWM outputs, and a given PWM output can be controlled by several temperature
|
||||
channels. As a result, the ADT747x may compute more than one PWM value
|
||||
for a channel at a given time, in which case the maximum value (fastest
|
||||
fan speed) is applied. PWM values range from 0 (off) to 255 (full speed).
|
||||
|
||||
tempX_offset Read/write the temperature adjustment offset
|
||||
Fan speed may be set to maximum when the temperature sensor associated with
|
||||
the PWM control exceeds temp#_max.
|
||||
|
||||
tempX_crit Read/write the THERM limit for remote1.
|
||||
Notes
|
||||
-----
|
||||
|
||||
tempX_crit_hyst Set the temperature value below crit where the
|
||||
fans will stay on - this helps drive the temperature
|
||||
low enough so it doesn't stay near the edge and
|
||||
cause THERM to keep tripping.
|
||||
|
||||
tempX_auto_point1_temp Read/write the minimum temperature where the fans will
|
||||
turn on in automatic mode.
|
||||
|
||||
tempX_auto_point2_temp Read/write the maximum temperature over which the fans
|
||||
will run in automatic mode. tempX_auto_point1_temp
|
||||
and tempX_auto_point2_temp together define the
|
||||
range of automatic control.
|
||||
|
||||
tempX_alarm Read a 1 if the max/min alarm is set
|
||||
tempX_fault Read a 1 if either temp1 or temp3 diode has a fault
|
||||
|
||||
(There are two voltage settings, in1 and in2):
|
||||
|
||||
inX_input Read the current voltage on VCC. Value is in
|
||||
millivolts.
|
||||
|
||||
inX_min read/write the minimum voltage limit.
|
||||
Dropping below this causes an alarm.
|
||||
|
||||
inX_max read/write the maximum voltage limit.
|
||||
Exceeding this causes an alarm.
|
||||
|
||||
inX_alarm Read a 1 if the max/min alarm is set.
|
||||
The nVidia binary driver presents an ADT7473 chip via an on-card i2c bus.
|
||||
Unfortunately, they fail to set the i2c adapter class, so this driver may
|
||||
fail to find the chip until the nvidia driver is patched.
|
||||
|
|
|
|||
Loading…
Reference in a new issue