[PATCH 1/4] dt-bindings: iio: adc: add bindings for AD4691 family

From: Radu Sabau via B4 Relay

Date: Thu Mar 05 2026 - 07:27:41 EST

From: Radu Sabau <radu.sabau@xxxxxxxxxx>

Add YAML bindings and dt-bindings header for the Analog Devices AD4691
family of multichannel SAR ADCs (AD4691, AD4692, AD4693, AD4694).

The binding describes five operating modes selectable via the
adi,spi-mode property, optional PWM/clock for CNV Clock and CNV Burst
modes, GPIO pins, voltage supplies and the trigger-source interface for
SPI Engine offload operation.

Signed-off-by: Radu Sabau <radu.sabau@xxxxxxxxxx>
---
.../devicetree/bindings/iio/adc/adi,ad4691.yaml | 278 +++++++++++++++++++++
MAINTAINERS | 8 +
include/dt-bindings/iio/adc/adi,ad4691.h | 13 +
3 files changed, 299 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad4691.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad4691.yaml
new file mode 100644
index 000000000000..b0d8036184b0
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4691.yaml
@@ -0,0 +1,278 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad4691.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD4691 Family Multichannel SAR ADCs
+
+maintainers:
+ - Radu Sabau <radu.sabau@xxxxxxxxxx>
+
+description: |
+ The AD4691 family are high-speed, low-power, multichannel successive
+ approximation register (SAR) analog-to-digital converters (ADCs) with
+ an SPI-compatible serial interface. The family supports multiple operating
+ modes including CNV Clock Mode, CNV Burst Mode, Autonomous Mode, SPI Burst
+ Mode, and Manual Mode.
+
+ The driver supports both standard SPI and SPI Engine (offload) operation.
+
+ Datasheets:
+ * https://www.analog.com/en/products/ad4692.html
+ * https://www.analog.com/en/products/ad4691.html
+ * https://www.analog.com/en/products/ad4694.html
+ * https://www.analog.com/en/products/ad4693.html
+
+$ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+ compatible:
+ enum:
+ - adi,ad4691
+ - adi,ad4692
+ - adi,ad4693
+ - adi,ad4694
+
+ reg:
+ maxItems: 1
+
+ spi-max-frequency:
+ maximum: 40000000
+
+ spi-cpol: true
+ spi-cpha: true
+
+ adi,spi-mode:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [0, 1, 2, 3, 4]
+ description: |
+ Selects the ADC operating mode:
+ 0 - CNV Clock Mode: External PWM drives CNV pin, samples at PWM rate.
+ 1 - CNV Burst Mode: PWM triggers burst cycles, internal oscillator
+ drives conversions within each burst.
+ 2 - Autonomous Mode: Internal oscillator drives conversions, software
+ starts/stops via register write.
+ 3 - SPI Burst Mode: Similar to Autonomous Mode but optimized for
+ SPI burst reads.
+ 4 - Manual Mode: CNV is directly tied to SPI CS. Each SPI transfer
+ triggers a conversion and returns previous result (pipelined).
+
+ vio-supply:
+ description: I/O voltage supply (1.71V to 1.89V or VDD).
+
+ vref-supply:
+ description:
+ External reference voltage supply (2.4V to 5.25V). Mutually exclusive
+ with vrefin-supply.
+
+ vrefin-supply:
+ description:
+ Internal reference buffer input supply. Mutually exclusive with
+ vref-supply.
+
+ reset-gpios:
+ description: GPIO connected to the RESET pin (active high).
+ maxItems: 1
+
+ gp0-gpios:
+ description:
+ GPIO connected to the GP0 pin. Required for non-offload operation to
+ receive DATA_READY or BUSY interrupts. For SPI Engine offload, this
+ is optional as the trigger is provided by the SPI offload subsystem.
+ maxItems: 1
+
+ gp1-gpios:
+ description: GPIO connected to the GP1 pin.
+ maxItems: 1
+
+ gp2-gpios:
+ description: GPIO connected to the GP2 pin.
+ maxItems: 1
+
+ gp3-gpios:
+ description: GPIO connected to the GP3 pin.
+ maxItems: 1
+
+ clocks:
+ description: Reference clock for PWM timing in CNV Clock and CNV Burst modes.
+ maxItems: 1
+
+ clock-names:
+ items:
+ - const: ref_clk
+
+ pwms:
+ description:
+ PWM connected to the CNV pin. Required for CNV Clock Mode and CNV Burst
+ Mode to control conversion timing.
+ maxItems: 1
+
+ pwm-names:
+ items:
+ - const: cnv
+
+ interrupts:
+ description:
+ Interrupt from the GP0 pin configured as DATA_READY or BUSY. Required
+ for non-offload operation in all modes except Manual Mode (mode 4),
+ where CNV is tied to CS and no DATA_READY signal is generated.
+ maxItems: 1
+
+ interrupt-names:
+ items:
+ - const: DRDY
+
+ '#trigger-source-cells':
+ description: |
+ For SPI Engine offload operation, this node acts as a trigger source.
+ Two cells are required:
+ - First cell: Trigger event type (0 = BUSY, 1 = DATA_READY)
+ - Second cell: GPIO pin number (only 0 = GP0 is supported)
+
+ Macros are available in dt-bindings/iio/adc/adi,ad4691.h:
+ AD4691_TRIGGER_EVENT_BUSY, AD4691_TRIGGER_EVENT_DATA_READY
+ AD4691_TRIGGER_PIN_GP0
+ const: 2
+
+required:
+ - compatible
+ - reg
+ - adi,spi-mode
+ - vio-supply
+ - reset-gpios
+
+allOf:
+ # vref-supply and vrefin-supply are mutually exclusive, one is required
+ - oneOf:
+ - required:
+ - vref-supply
+ - required:
+ - vrefin-supply
+
+ # AD4694 (20-bit) does not support Manual Mode
+ - if:
+ properties:
+ compatible:
+ const: adi,ad4694
+ then:
+ properties:
+ adi,spi-mode:
+ enum: [0, 1, 2, 3]
+
+ # CNV Clock Mode and CNV Burst Mode require PWM and clock
+ - if:
+ properties:
+ adi,spi-mode:
+ enum: [0, 1]
+ then:
+ required:
+ - clocks
+ - clock-names
+ - pwms
+ - pwm-names
+
+ # Non-Manual modes (0-3) without SPI offload require a DRDY interrupt.
+ # Offload configurations expose '#trigger-source-cells' instead.
+ - if:
+ properties:
+ adi,spi-mode:
+ enum: [0, 1, 2, 3]
+ not:
+ required:
+ - '#trigger-source-cells'
+ then:
+ required:
+ - interrupts
+ - interrupt-names
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ #include <dt-bindings/iio/adc/adi,ad4691.h>
+
+ /* Example: AD4692 in CNV Clock Mode with standard SPI */
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ adc@0 {
+ compatible = "adi,ad4692";
+ reg = <0>;
+ spi-cpol;
+ spi-cpha;
+ spi-max-frequency = <40000000>;
+
+ adi,spi-mode = <0>; /* CNV Clock Mode */
+
+ vio-supply = <&vio_supply>;
+ vref-supply = <&vref_5v>;
+
+ reset-gpios = <&gpio 10 GPIO_ACTIVE_HIGH>;
+ gp0-gpios = <&gpio 11 GPIO_ACTIVE_HIGH>;
+
+ clocks = <&ref_clk>;
+ clock-names = "ref_clk";
+
+ pwms = <&pwm_gen 0 0>;
+ pwm-names = "cnv";
+
+ interrupts = <12 4>;
+ interrupt-names = "DRDY";
+ };
+ };
+
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ #include <dt-bindings/iio/adc/adi,ad4691.h>
+
+ /* Example: AD4692 in Manual Mode with SPI Engine offload */
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ adc@0 {
+ compatible = "adi,ad4692";
+ reg = <0>;
+ spi-cpol;
+ spi-cpha;
+ spi-max-frequency = <31250000>;
+
+ adi,spi-mode = <4>; /* Manual Mode */
+
+ vio-supply = <&vio_supply>;
+ vrefin-supply = <&vrefin_supply>;
+
+ reset-gpios = <&gpio 10 GPIO_ACTIVE_HIGH>;
+ };
+ };
+
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ #include <dt-bindings/iio/adc/adi,ad4691.h>
+
+ /* Example: AD4691 in Autonomous Mode with SPI Engine offload trigger */
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ adc@0 {
+ compatible = "adi,ad4691";
+ reg = <0>;
+ spi-cpol;
+ spi-cpha;
+ spi-max-frequency = <40000000>;
+
+ adi,spi-mode = <2>; /* Autonomous Mode */
+
+ vio-supply = <&vio_supply>;
+ vref-supply = <&vref_5v>;
+
+ reset-gpios = <&gpio 10 GPIO_ACTIVE_HIGH>;
+ gp0-gpios = <&gpio 11 GPIO_ACTIVE_HIGH>;
+
+ #trigger-source-cells = <2>;
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 61bf550fd37c..9994d107d88d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1484,6 +1484,14 @@ W: https://ez.analog.com/linux-software-drivers
F: Documentation/devicetree/bindings/iio/adc/adi,ad4170-4.yaml
F: drivers/iio/adc/ad4170-4.c

+ANALOG DEVICES INC AD4691 DRIVER
+M: Radu Sabau <radu.sabau@xxxxxxxxxx>
+L: linux-iio@xxxxxxxxxxxxxxx
+S: Supported
+W: https://ez.analog.com/linux-software-drivers
+F: Documentation/devicetree/bindings/iio/adc/adi,ad4691.yaml
+F: include/dt-bindings/iio/adc/adi,ad4691.h
+
ANALOG DEVICES INC AD4695 DRIVER
M: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
M: Nuno Sá <nuno.sa@xxxxxxxxxx>
diff --git a/include/dt-bindings/iio/adc/adi,ad4691.h b/include/dt-bindings/iio/adc/adi,ad4691.h
new file mode 100644
index 000000000000..294b03974f48
--- /dev/null
+++ b/include/dt-bindings/iio/adc/adi,ad4691.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+
+#ifndef _DT_BINDINGS_ADI_AD4691_H
+#define _DT_BINDINGS_ADI_AD4691_H
+
+/* Trigger event types */
+#define AD4691_TRIGGER_EVENT_BUSY 0
+#define AD4691_TRIGGER_EVENT_DATA_READY 1
+
+/* Trigger GPIO pin selection */
+#define AD4691_TRIGGER_PIN_GP0 0
+
+#endif /* _DT_BINDINGS_ADI_AD4691_H */

--
2.43.0