Documentation/hwmon/adt7475.rst

Source file repositories/reference/linux-study-clean/Documentation/hwmon/adt7475.rst

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Linux kernel
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Documentation/hwmon/adt7475.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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atlas-only

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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 adt7475
=====================

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

  * Analog Devices ADT7476

    Prefix: 'adt7476'

    Addresses scanned: I2C 0x2C, 0x2D, 0x2E

    Datasheet: Publicly available at the On Semiconductors website

  * Analog Devices ADT7490

    Prefix: 'adt7490'

    Addresses scanned: I2C 0x2C, 0x2D, 0x2E

    Datasheet: Publicly available at the On Semiconductors website

Authors:
	- Jordan Crouse
	- Hans de Goede
	- Darrick J. Wong (documentation)
	- Jean Delvare


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

This driver implements support for the Analog Devices ADT7473, ADT7475,
ADT7476 and ADT7490 chip family. The ADT7473 and ADT7475 differ only in
minor details. The ADT7476 has additional features, including extra voltage
measurement inputs and VID support. The ADT7490 also has additional
features, including extra voltage measurement inputs and PECI support. All
the supported chips will be collectively designed by the name "ADT747x" in
the rest of this document.

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) or more 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.

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.

Each of the measured inputs (voltage, temperature, fan speed) has
corresponding high/low limit values. The ADT747x will signal an ALARM if

Annotation

Implementation Notes