hwmon: (nct6775) Add support for automatic fan control

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Guenter Roeck 2012-12-04 09:04:52 -08:00
parent 77eb5b3703
commit cdcaeceb74
2 changed files with 1161 additions and 7 deletions

View File

@ -87,6 +87,75 @@ pwm[1-5]_mode - controls if output is PWM or DC level
* 0 DC output
* 1 PWM output
Common fan control attributes
-----------------------------
pwm[1-5]_temp_sel Temperature source. Value is temperature sensor index.
For example, select '1' for temp1_input.
Thermal Cruise mode (2)
-----------------------
If the temperature is in the range defined by:
pwm[1-5]_target_temp Target temperature, unit millidegree Celsius
(range 0 - 127000)
pwm[1-5]_temp_tolerance
Target temperature tolerance, unit millidegree Celsius
there are no changes to fan speed. Once the temperature leaves the interval, fan
speed increases (if temperature is higher that desired) or decreases (if
temperature is lower than desired), using the following limits and time
intervals.
pwm[1-5]_start fan pwm start value (range 1 - 255), to start fan
when the temperature is above defined range.
pwm[1-5]_floor lowest fan pwm (range 0 - 255) if temperature is below
the defined range. If set to 0, the fan is expected to
stop if the temperature is below the defined range.
pwm[1-5]_step_up_time milliseconds before fan speed is increased
pwm[1-5]_step_down_time milliseconds before fan speed is decreased
pwm[1-5]_stop_time how many milliseconds must elapse to switch
corresponding fan off (when the temperature was below
defined range).
Speed Cruise mode (3)
---------------------
This modes tries to keep the fan speed constant.
fan[1-5]_target Target fan speed
fan[1-5]_tolerance
Target speed tolerance
Untested; use at your own risk.
Smart Fan IV mode (5)
---------------------
This mode offers multiple slopes to control the fan speed. The slopes can be
controlled by setting the pwm and temperature attributes. When the temperature
rises, the chip will calculate the DC/PWM output based on the current slope.
There are up to seven data points depending on the chip type. Subsequent data
points should be set to higher temperatures and higher pwm values to achieve
higher fan speeds with increasing temperature. The last data point reflects
critical temperature mode, in which the fans should run at full speed.
pwm[1-5]_auto_point[1-7]_pwm
pwm value to be set if temperature reaches matching
temperature range.
pwm[1-5]_auto_point[1-7]_temp
Temperature over which the matching pwm is enabled.
pwm[1-5]_temp_tolerance
Temperature tolerance, unit millidegree Celsius
pwm[1-5]_crit_temp_tolerance
Temperature tolerance for critical temperature,
unit millidegree Celsius
pwm[1-5]_step_up_time milliseconds before fan speed is increased
pwm[1-5]_step_down_time milliseconds before fan speed is decreased
Usage Notes
-----------

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