[PATCH 1/4] dt-bindings: iio: adc: add ti,ads122c14

From: David Lechner (TI)

Date: Mon Jun 15 2026 - 18:02:21 EST

Add new bindings for ti,ads122c14 and similar devices.

This is an ADC that is primarily intended for use with temperature
sensors. There are a few unusual properties because of this. In
particular, the reference voltage source and current output requirements
can be different for each measurement, so these are included in the
channel bindings.

The REFP/REFN reference voltage is usually just connected to a resistor
that is being driven by the ADC's current outputs, so there is special
property for this case rather than requiring a regulator to be defined
to represent that.

ti,vref-source is reused from ti,tlv320adcx140.yaml (otherwise might
have preferred an enum of strings).

Signed-off-by: David Lechner (TI) <dlechner@xxxxxxxxxxxx>
---
.../devicetree/bindings/iio/adc/ti,ads112c14.yaml | 224 +++++++++++++++++++++
MAINTAINERS | 7 +
include/dt-bindings/iio/adc/ti,ads112c14.h | 11 +
3 files changed, 242 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml
new file mode 100644
index 000000000000..dc7f37cad772
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml
@@ -0,0 +1,224 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,ads112c14.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments' ADS112C14 and similar ADC chips
+
+description: |
+ Supports the following Texas Instruments' ADC chips:
+ - ADS112C14 (16-bit)
+ - ADS122C14 (24-bit)
+
+ https://www.ti.com/lit/ds/symlink/ads122c14.pdf
+
+ These chips are primarily designed for use with temperature sensors such as
+ RTDs and thermocouples. The channel bindings reflect this in that each channel
+ represents the conditions required to make a measurement rather than strictly
+ just the physical input channels.
+
+maintainers:
+ - David Lechner <dlechner@xxxxxxxxxxxx>
+
+unevaluatedProperties: false
+
+properties:
+ compatible:
+ enum:
+ - ti,ads112c14
+ - ti,ads122c14
+
+ reg:
+ items:
+ - minimum: 0x40
+ maximum: 0x47
+
+ clocks:
+ maxItems: 1
+ description: Optional external clock connected to GPIO3 pin.
+
+ avdd-supply: true
+ dvdd-supply: true
+
+ refp-supply: true
+ refn-supply: true
+
+ refp-refn-resistor-ohms:
+ description:
+ The resistance of the external resistor between REFP and REFN when using
+ resistor bridge driven by current outputs for RTD measurements.
+
+ interrupts:
+ minItems: 1
+ items:
+ - description: FAULT interrupt (GPIO2 pin)
+ - description: DRDY interrupt (GPIO3 pin)
+
+ interrupt-names:
+ minItems: 1
+ maxItems: 2
+ items:
+ enum: [fault, drdy]
+
+ gpio-controller: true
+ '#gpio-cells':
+ const: 2
+
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+patternProperties:
+ ^channel@[0-7]$:
+ $ref: adc.yaml
+
+ unevaluatedProperties: false
+
+ properties:
+ reg:
+ maximum: 16 # arbitrary limit, channel@ can be any combination of AIN0-AIN7
+
+ single-channel:
+ maximum: 7
+
+ diff-channels:
+ items:
+ maximum: 7
+
+ bipolar:
+ description:
+ Set this flag if the differential input can be negative.
+
+ excitation-channels:
+ description: AINx pins used as current output.
+ $ref: /schemas/types.yaml#/definitions/uint32-array
+ minItems: 1
+ maxItems: 2
+ items:
+ maximum: 7
+
+ excitation-current-microamp:
+ description: The current output of the excitation channels in microamps.
+ minimum: 1
+ maximum: 1000
+
+ current-chopping:
+ $ref: /schemas/types.yaml#/definitions/flag
+ description:
+ If provided, the two excitation channels are to be used with current
+ chopping enabled.
+
+ ti,vref-source:
+ description: |
+ Indicates the source for the reference voltage for this channel.
+ 0 - Internal 2.5V reference
+ 1 - Internal 1.25V reference
+ 2 - External reference (REFP-REFN)
+ 3 - AVDD as reference
+
+ For convenience, macros for these values are available in
+ dt-bindings/iio/adc/ti,ads112c14.h.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maximum: 3
+ default: 0
+
+ dependencies:
+ excitation-channels: [ excitation-current-microamp ]
+ excitation-current-microamp: [ excitation-channels ]
+ current-chopping: [ excitation-channels ]
+
+ oneOf:
+ - required: [ single-channel ]
+ - required: [ diff-channels ]
+
+required:
+ - compatible
+ - reg
+ - avdd-supply
+ - dvdd-supply
+
+dependencies:
+ refn-supply: [ refp-supply ]
+
+allOf:
+ - oneOf:
+ - required: [ refp-supply ]
+ - required: [ refp-refn-resistor-ohms ]
+ - properties:
+ refp-supply: false
+ refn-supply: false
+ refp-refn-resistor-ohms: false
+
+examples:
+ - |
+ #include <dt-bindings/iio/adc/ti,ads112c14.h>
+
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ adc@40 {
+ compatible = "ti,ads112c14";
+ reg = <0x40>;
+
+ avdd-supply = <&avdd>;
+ dvdd-supply = <&dvdd>;
+
+ /* 3-Wire RTD: Two IDACs, One Measurement (AIN1-AIN2) */
+
+ refp-refn-resistor-ohms = <500>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ channel@0 {
+ reg = <0>;
+ diff-channels = <1>, <2>;
+ excitation-channels = <0>, <3>;
+ excitation-current-microamp = <500>;
+ current-chopping;
+ ti,vref-source = <ADS112C14_VREF_SOURCE_EXTERNAL>;
+ label = "rtd";
+ };
+ };
+ };
+ - |
+ #include <dt-bindings/iio/adc/ti,ads112c14.h>
+
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ adc@40 {
+ compatible = "ti,ads112c14";
+ reg = <0x40>;
+
+ avdd-supply = <&avdd>;
+ dvdd-supply = <&dvdd>;
+
+ /* Resistive Bridge Measurement With a Thermistor for Temperature Compensation*/
+
+ refp-supply = <&avdd>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ channel@0 {
+ reg = <0>;
+ diff-channels = <6>, <7>;
+ bipolar;
+ ti,vref-source = <ADS112C14_VREF_SOURCE_EXTERNAL>;
+ label = "bridge";
+ };
+
+ channel@1 {
+ reg = <1>;
+ diff-channels = <1>, <2>;
+ ti,vref-source = <ADS112C14_VREF_SOURCE_INTERNAL_2_5V>;
+ label = "thermistor";
+ };
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index f1caa6e5198b..9ce7c61b0c14 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -26911,6 +26911,13 @@ S: Maintained
F: Documentation/devicetree/bindings/iio/adc/ti,ads1119.yaml
F: drivers/iio/adc/ti-ads1119.c

+TI ADS112C14 ADC DRIVER
+M: David Lechner <dlechner@xxxxxxxxxxxx>
+L: linux-iio@xxxxxxxxxxxxxxx
+S: Maintained
+F: Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml
+F: include/dt-bindings/iio/adc/ti,ads112c14.h
+
TI ADS1018 ADC DRIVER
M: Kurt Borja <kuurtb@xxxxxxxxx>
L: linux-iio@xxxxxxxxxxxxxxx
diff --git a/include/dt-bindings/iio/adc/ti,ads112c14.h b/include/dt-bindings/iio/adc/ti,ads112c14.h
new file mode 100644
index 000000000000..96906642fe41
--- /dev/null
+++ b/include/dt-bindings/iio/adc/ti,ads112c14.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+
+#ifndef _DT_BINDINGS_TI_ADS112C14_H
+#define _DT_BINDINGS_TI_ADS112C14_H
+
+#define ADS112C14_VREF_SOURCE_INTERNAL_2_5V 0
+#define ADS112C14_VREF_SOURCE_INTERNAL_1_25V 1
+#define ADS112C14_VREF_SOURCE_EXTERNAL 2
+#define ADS112C14_VREF_SOURCE_AVDD 3
+
+#endif /* _DT_BINDINGS_TI_ADS112C14_H */

--
2.43.0