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hwmon/f71805f: Add temperature-tracking fan control mode

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Add support for the "temperature mode" fan speed control. In this mode,
the user can define 3 temperature/speed trip points, and the chip will
set the speed automatically according to the temperature changes.

Signed-off-by: Phil Endecott <kernel@chezphil.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
This commit is contained in:
Phil Endecott
2007-06-29 09:19:14 +02:00
committed by Mark M. Hoffman
parent 158ce07564
commit aba5073d3f
2 changed files with 188 additions and 14 deletions
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Documentation/hwmon/f71805f
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@@ -5,11 +5,11 @@ Supported chips:
* Fintek F71805F/FG
Prefix: 'f71805f'
Addresses scanned: none, address read from Super I/O config space
Datasheet: Provided by Fintek on request
Datasheet: Available from the Fintek website
* Fintek F71872F/FG
Prefix: 'f71872f'
Addresses scanned: none, address read from Super I/O config space
Datasheet: Provided by Fintek on request
Datasheet: Available from the Fintek website
Author: Jean Delvare <khali@linux-fr.org>
@@ -128,7 +128,9 @@ it.
When the PWM method is used, you can select the operating frequency,
from 187.5 kHz (default) to 31 Hz. The best frequency depends on the
fan model. As a rule of thumb, lower frequencies seem to give better
control, but may generate annoying high-pitch noise. Fintek recommends
control, but may generate annoying high-pitch noise. So a frequency just
above the audible range, such as 25 kHz, may be a good choice; if this
doesn't give you good linear control, try reducing it. Fintek recommends
not going below 1 kHz, as the fan tachometers get confused by lower
frequencies as well.
@@ -136,16 +138,23 @@ When the DC method is used, Fintek recommends not going below 5 V, which
corresponds to a pwm value of 106 for the driver. The driver doesn't
enforce this limit though.
Three different fan control modes are supported:
Three different fan control modes are supported; the mode number is written
to the pwm<n>_enable file.
* Manual mode
You ask for a specific PWM duty cycle or DC voltage.
* 1: Manual mode
You ask for a specific PWM duty cycle or DC voltage by writing to the
pwm<n> file.
* Fan speed mode
You ask for a specific fan speed. This mode assumes that pwm1
corresponds to fan1, pwm2 to fan2 and pwm3 to fan3.
* 2: Temperature mode
You define 3 temperature/fan speed trip points using the
pwm<n>_auto_point<m>_temp and _fan files. These define a staircase
relationship between temperature and fan speed with two additional points
interpolated between the values that you define. When the temperature
is below auto_point1_temp the fan is switched off.
* Temperature mode
You define 3 temperature/fan speed trip points, and the fan speed is
adjusted depending on the measured temperature, using interpolation.
This mode is not yet supported by the driver.
* 3: Fan speed mode
You ask for a specific fan speed by writing to the fan<n>_target file.
Both of the automatic modes require that pwm1 corresponds to fan1, pwm2 to
fan2 and pwm3 to fan3. Temperature mode also requires that temp1 corresponds
to pwm1 and fan1, etc.