Documentation/hwmon/smsc47m192.rst

Source file repositories/reference/linux-study-clean/Documentation/hwmon/smsc47m192.rst

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Linux kernel
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Documentation/hwmon/smsc47m192.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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Annotated Snippet

Kernel driver smsc47m192
========================

Supported chips:

  * SMSC LPC47M192, LPC47M15x, LPC47M292 and LPC47M997

    Prefix: 'smsc47m192'

    Addresses scanned: I2C 0x2c - 0x2d

    Datasheet: The datasheet for LPC47M192 is publicly available from

	       http://www.smsc.com/

	       The LPC47M15x, LPC47M292 and LPC47M997 are compatible for

	       hardware monitoring.



Author:
      - Hartmut Rick <linux@rick.claranet.de>

      - Special thanks to Jean Delvare for careful checking
	of the code and many helpful comments and suggestions.


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

This driver implements support for the hardware sensor capabilities
of the SMSC LPC47M192 and compatible Super-I/O chips.

These chips support 3 temperature channels and 8 voltage inputs
as well as CPU voltage VID input.

They do also have fan monitoring and control capabilities, but the
these features are accessed via ISA bus and are not supported by this
driver. Use the 'smsc47m1' driver for fan monitoring and control.

Voltages and temperatures are measured by an 8-bit ADC, the resolution
of the temperatures is 1 bit per degree C.
Voltages are scaled such that the nominal voltage corresponds to
192 counts, i.e. 3/4 of the full range. Thus the available range for
each voltage channel is 0V ... 255/192*(nominal voltage), the resolution
is 1 bit per (nominal voltage)/192.
Both voltage and temperature values are scaled by 1000, the sys files
show voltages in mV and temperatures in units of 0.001 degC.

The +12V analog voltage input channel (in4_input) is multiplexed with
bit 4 of the encoded CPU voltage. This means that you either get
a +12V voltage measurement or a 5 bit CPU VID, but not both.
The default setting is to use the pin as 12V input, and use only 4 bit VID.
This driver assumes that the information in the configuration register
is correct, i.e. that the BIOS has updated the configuration if
the motherboard has this input wired to VID4.

The temperature and voltage readings are updated once every 1.5 seconds.
Reading them more often repeats the same values.


sysfs interface
---------------

===================== ==========================================================
in0_input	      +2.5V voltage input
in1_input	      CPU voltage input (nominal 2.25V)
in2_input	      +3.3V voltage input
in3_input	      +5V voltage input

Annotation

Implementation Notes