dt-bindings: iio: adc: Split out QCOM VADC channel properties

Split out the common channel properties for QCOM VADC devices into a
separate file so that it can be included as a reference for devices
using them. This will be needed for the upcoming ADC5 Gen3 binding
support patch, as ADC5 Gen3 also uses all of these common properties.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jishnu Prakash <jishnu.prakash@oss.qualcomm.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Jishnu Prakash 2026-01-30 17:24:18 +05:30 committed by Jonathan Cameron
parent 6de23f81a5
commit 9f3a352e9f
2 changed files with 86 additions and 74 deletions

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@ -0,0 +1,84 @@
# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/adc/qcom,spmi-vadc-common.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Qualcomm Technologies, Inc. SPMI PMIC ADC channels
maintainers:
- Jishnu Prakash <jishnu.prakash@oss.qualcomm.com>
description:
This defines the common properties used to define Qualcomm VADC channels.
properties:
reg:
description:
ADC channel number (PMIC-specific for versions after PMIC5 ADC).
maxItems: 1
label:
description:
ADC input of the platform as seen in the schematics.
For thermistor inputs connected to generic AMUX or GPIO inputs
these can vary across platform for the same pins. Hence select
the platform schematics name for this channel.
qcom,decimation:
$ref: /schemas/types.yaml#/definitions/uint32
description:
This parameter is used to decrease ADC sampling rate.
Quicker measurements can be made by reducing decimation ratio.
qcom,pre-scaling:
$ref: /schemas/types.yaml#/definitions/uint32-array
description:
Used for scaling the channel input signal before the signal is
fed to VADC. The configuration for this node is to know the
pre-determined ratio and use it for post scaling. It is a pair of
integers, denoting the numerator and denominator of the fraction by which
input signal is multiplied. For example, <1 3> indicates the signal is scaled
down to 1/3 of its value before ADC measurement.
If property is not found default value depending on chip will be used.
oneOf:
- items:
- const: 1
- enum: [ 1, 3, 4, 6, 20, 8, 10, 16 ]
- items:
- const: 10
- const: 81
qcom,ratiometric:
type: boolean
description: |
Channel calibration type.
- For compatible property "qcom,spmi-vadc", if this property is
specified VADC will use the VDD reference (1.8V) and GND for
channel calibration. If property is not found, channel will be
calibrated with 0.625V and 1.25V reference channels, also
known as absolute calibration.
- For other compatible properties, if this property is specified
VADC will use the VDD reference (1.875V) and GND for channel
calibration. If property is not found, channel will be calibrated
with 0V and 1.25V reference channels, also known as absolute calibration.
qcom,hw-settle-time:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Time between AMUX getting configured and the ADC starting
conversion. The 'hw_settle_time' is an index used from valid values
and programmed in hardware to achieve the hardware settling delay.
qcom,avg-samples:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Number of samples to be used for measurement.
Averaging provides the option to obtain a single measurement
from the ADC that is an average of multiple samples. The value
selected is 2^(value).
required:
- reg
additionalProperties: true

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@ -56,7 +56,7 @@ required:
patternProperties:
"^channel@[0-9a-f]+$":
type: object
additionalProperties: false
unevaluatedProperties: false
description: |
Represents the external channels which are connected to the ADC.
For compatible property "qcom,spmi-vadc" following channels, also known as
@ -64,79 +64,7 @@ patternProperties:
configuration nodes should be defined:
VADC_REF_625MV and/or VADC_SPARE1(based on PMIC version) VADC_REF_1250MV,
VADC_GND_REF and VADC_VDD_VADC.
properties:
reg:
maxItems: 1
description: |
ADC channel number.
See include/dt-bindings/iio/qcom,spmi-vadc.h
For PMIC7 ADC, the channel numbers are specified separately per PMIC
in the PMIC-specific files in include/dt-bindings/iio/.
label:
description: |
ADC input of the platform as seen in the schematics.
For thermistor inputs connected to generic AMUX or GPIO inputs
these can vary across platform for the same pins. Hence select
the platform schematics name for this channel.
qcom,decimation:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
This parameter is used to decrease ADC sampling rate.
Quicker measurements can be made by reducing decimation ratio.
qcom,pre-scaling:
description: |
Used for scaling the channel input signal before the signal is
fed to VADC. The configuration for this node is to know the
pre-determined ratio and use it for post scaling. It is a pair of
integers, denoting the numerator and denominator of the fraction by which
input signal is multiplied. For example, <1 3> indicates the signal is scaled
down to 1/3 of its value before ADC measurement.
If property is not found default value depending on chip will be used.
$ref: /schemas/types.yaml#/definitions/uint32-array
oneOf:
- items:
- const: 1
- enum: [ 1, 3, 4, 6, 20, 8, 10, 16 ]
- items:
- const: 10
- const: 81
qcom,ratiometric:
description: |
Channel calibration type.
- For compatible property "qcom,spmi-vadc", if this property is
specified VADC will use the VDD reference (1.8V) and GND for
channel calibration. If property is not found, channel will be
calibrated with 0.625V and 1.25V reference channels, also
known as absolute calibration.
- For compatible property "qcom,spmi-adc5", "qcom,spmi-adc7" and
"qcom,spmi-adc-rev2", if this property is specified VADC will use
the VDD reference (1.875V) and GND for channel calibration. If
property is not found, channel will be calibrated with 0V and 1.25V
reference channels, also known as absolute calibration.
type: boolean
qcom,hw-settle-time:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Time between AMUX getting configured and the ADC starting
conversion. The 'hw_settle_time' is an index used from valid values
and programmed in hardware to achieve the hardware settling delay.
qcom,avg-samples:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
Number of samples to be used for measurement.
Averaging provides the option to obtain a single measurement
from the ADC that is an average of multiple samples. The value
selected is 2^(value).
required:
- reg
$ref: /schemas/iio/adc/qcom,spmi-vadc-common.yaml
allOf:
- if: