Documentation/hwmon/vt1211.rst

Source file repositories/reference/linux-study-clean/Documentation/hwmon/vt1211.rst

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Linux kernel
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Documentation/hwmon/vt1211.rst
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.rst
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Support Tooling And Documentation
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Documentation
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Support Tooling And Documentation: documentation
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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Kernel driver vt1211
====================

Supported chips:

  * VIA VT1211

    Prefix: 'vt1211'

    Addresses scanned: none, address read from Super-I/O config space

    Datasheet: Provided by VIA upon request and under NDA

Authors: Juerg Haefliger <juergh@gmail.com>

This driver is based on the driver for kernel 2.4 by Mark D. Studebaker and
its port to kernel 2.6 by Lars Ekman.

Thanks to Joseph Chan and Fiona Gatt from VIA for providing documentation and
technical support.


Module Parameters
-----------------


* uch_config: int
			Override the BIOS default universal channel (UCH)
			configuration for channels 1-5.
			Legal values are in the range of 0-31. Bit 0 maps to
			UCH1, bit 1 maps to UCH2 and so on. Setting a bit to 1
			enables the thermal input of that particular UCH and
			setting a bit to 0 enables the voltage input.

* int_mode: int
			Override the BIOS default temperature interrupt mode.
			The only possible value is 0 which forces interrupt
			mode 0. In this mode, any pending interrupt is cleared
			when the status register is read but is regenerated as
			long as the temperature stays above the hysteresis
			limit.

Be aware that overriding BIOS defaults might cause some unwanted side effects!


Description
-----------

The VIA VT1211 Super-I/O chip includes complete hardware monitoring
capabilities. It monitors 2 dedicated temperature sensor inputs (temp1 and
temp2), 1 dedicated voltage (in5) and 2 fans. Additionally, the chip
implements 5 universal input channels (UCH1-5) that can be individually
programmed to either monitor a voltage or a temperature.

This chip also provides manual and automatic control of fan speeds (according
to the datasheet). The driver only supports automatic control since the manual
mode doesn't seem to work as advertised in the datasheet. In fact I couldn't
get manual mode to work at all! Be aware that automatic mode hasn't been
tested very well (due to the fact that my EPIA M10000 doesn't have the fans
connected to the PWM outputs of the VT1211 :-().

The following table shows the relationship between the vt1211 inputs and the
sysfs nodes.

=============== ============== =========== ================================
Sensor          Voltage Mode   Temp Mode   Default Use (from the datasheet)
=============== ============== =========== ================================
Reading 1                      temp1       Intel thermal diode
Reading 3                      temp2       Internal thermal diode
UCH1/Reading2   in0            temp3       NTC type thermistor

Annotation

Implementation Notes