Documentation/devicetree/bindings/iio/afe/temperature-transducer.yaml

Source file repositories/reference/linux-study-clean/Documentation/devicetree/bindings/iio/afe/temperature-transducer.yaml

File Facts

System
Linux kernel
Corpus path
Documentation/devicetree/bindings/iio/afe/temperature-transducer.yaml
Extension
.yaml
Size
3714 bytes
Lines
115
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: configuration, schema, or hardware description
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/afe/temperature-transducer.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Temperature Transducer

maintainers:
  - Liam Beguin <liambeguin@gmail.com>

description: |
  A temperature transducer is a device that converts a thermal quantity
  into any other physical quantity. This binding applies to temperature to
  voltage (like the LTC2997), and temperature to current (like the AD590)
  linear transducers.
  In both cases these are assumed to be connected to a voltage ADC.

  When an io-channel measures the output voltage of a temperature analog front
  end such as a temperature transducer, the interesting measurement is almost
  always the corresponding temperature, not the voltage output. This binding
  describes such a circuit.

  The general transfer function here is (using SI units)
    V(T) = Rsense * Isense(T)
    T = (Isense(T) / alpha) + offset
    T = 1 / (Rsense * alpha) * (V + offset * Rsense * alpha)

  When using a temperature to voltage transducer, Rsense is set to 1.

  The following circuits show a temperature to current and a temperature to
  voltage transducer that can be used with this binding.

           VCC
          -----
            |
        +---+---+
        | AD590 |                               VCC
        +---+---+                              -----
            |                                    |
            V proportional to T             +----+----+
            |                          D+ --+         |
            +---- Vout                      | LTC2997 +--- Vout
            |                          D- --+         |
        +---+----+                          +---------+
        | Rsense |                               |
        +---+----+                             -----
            |                                   GND
          -----
           GND

properties:
  compatible:
    const: temperature-transducer

  io-channels:
    maxItems: 1
    description: |
      Channel node of a voltage io-channel.

  '#io-channel-cells':
    const: 0

  sense-offset-millicelsius:
    description: |
      Temperature offset.
      This offset is commonly used to convert from Kelvins to degrees Celsius.
      In that case, sense-offset-millicelsius would be set to <(-273150)>.
    default: 0

Annotation

Implementation Notes