Add Support for ADMT4000

Documentation/ABI/testing/sysfs-bus-iio-position-admt4000

@@ -0,0 +1,41 @@
+What:		/sys/bus/iio/devices/deviceX/in_angl_h1ph_corr
+What:		/sys/bus/iio/devices/deviceX/in_angl_h2ph_corr
+What:		/sys/bus/iio/devices/deviceX/in_angl_h3ph_corr
+What:		/sys/bus/iio/devices/deviceX/in_angl_h8ph_corr
+KernelVersion:	6.6.0
+Contact:	[email protected]
+Description:
+	These attributes expose per-harmonic phase correction angles used by the
+	device to compensate for phase errors in signal measurement. Each attribute
+	corresponds to a specific harmonic order (h1, h2, h3, h8).
+
+What:		/sys/bus/iio/devices/deviceX/in_angl_h1mag_corr
+What:		/sys/bus/iio/devices/deviceX/in_angl_h2mag_corr
+What:		/sys/bus/iio/devices/deviceX/in_angl_h3mag_corr
+What:		/sys/bus/iio/devices/deviceX/in_angl_h8mag_corr
+KernelVersion:	6.6.0
+Contact:	[email protected]
+Description:
+	These attributes expose per-harmonic magnitude correction factors used by
+	the device to compensate for amplitude errors in harmonic signal measurement.
+	Each attribute corresponds to a specific harmonic order (h1, h2, h3, h8).
+
+What:		/sys/bus/iio/devices/deviceX/in_angl_h8_corr_src
+KernelVersion:	6.6.0
+Contact:	[email protected]
+Description:
+	This attribute selects the source of the correction coefficients for the 8th
+	harmonic angular measurement.
+
+What:		/sys/bus/iio/devices/deviceX/in_angl_h8_corr_src_available
+KernelVersion:	6.6.0
+Contact:	[email protected]
+Description:
+	Supported values are "factory" for built-in device calibration and "user"
+	for software-provided calibration data.
+
+What:		/sys/bus/iio/devices/deviceX/in_angl_filter_en
+KernelVersion:	6.6.0
+Contact:	[email protected]
+Description:
+	Enable or disable the device's angle measurement filter.

Documentation/devicetree/bindings/iio/position/adi,admt4000.yaml

@@ -0,0 +1,85 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright (c) 2025 Analog Devices, Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/position/adi,admt4000.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices ADMT4000 True Power-On Multiturn Sensor
+maintainers:
+  - Celine Joy Capua <[email protected]>
+
+description: |
+  The ADMT4000 is a magnetic turn count sensor capable of recording the number
+  of rotations of a magnetic system even while the device is powered down. On
+  power-up, the device can be interrogated to report the absolute position of
+  the system. Datasheet can be found here:
+  https://www.analog.com/media/en/technical-documentation/data-sheets/admt4000.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,admt4000
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 10000000
+
+  vdd-supply:
+    description: Power Supply Input.
+
+  acalc-gpios:
+    description:
+      Angle Calculation Status. Indicates when the angle is being calculated.
+    maxItems: 1
+
+  busy-gpios:
+    description:
+      Busy indicator gpio. Indicates when the part is performing measurement.
+    maxItems: 1
+
+  cnv-gpios:
+    description:
+      Conversion start gpio. Used when an external convert start
+      signal is desired. If not present, the conversion start is done via device
+      registers.
+    maxItems: 1
+
+  adi,one-shot-conversion:
+    description:
+      If present, this indicates that the device is operation at a one-shot
+      conversion mode.
+    type: boolean
+
+  adi,cnv-sync-mode:
+    description:
+      Convert start synchronization mode.
+    enum: [seq_ctrl, start_edge]
+    default: seq_ctrl
+
+required:
+  - compatible
+  - reg
+  - vdd-supply
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      pos@0 {
+        compatible = "adi,admt4000";
+        reg = <0>;
+        spi-max-frequency = <1000000>;
+
+        vdd-supply = <&vdd>;
+      };
+    };
+...

drivers/iio/Kconfig.adi

@@ -216,3 +216,5 @@ config IIO_ALL_ADI_DRIVERS
 	imply LTC2309
 	imply AD7091R8
 	imply AD9739A
+	imply ADMT4000_POS
+

drivers/iio/position/Kconfig

@@ -6,6 +6,18 @@
 
 menu "Linear and angular position sensors"
 
+config ADMT4000_POS
+	tristate "ADMT4000 true power-on multiturn sensor"
+	depends on SPI
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+		Say yes here to build support for Analog Devices ADMT4000 True Power-On
+		Multiturn Sensor.
+
+		To compile this driver as a module, choose M here: the
+		module will be called admt4000.
+
 config IQS624_POS
 	tristate "Azoteq IQS624/625 angular position sensors"
 	depends on MFD_IQS62X || COMPILE_TEST

drivers/iio/position/Makefile

@@ -4,5 +4,7 @@
 
 # When adding new entries keep the list in alphabetical order
 
+obj-$(CONFIG_ADMT4000_POS) += admt4000.o
+obj-$(CONFIG_ADMT4000_ADG714) += adg714.o
 obj-$(CONFIG_HID_SENSOR_CUSTOM_INTEL_HINGE) += hid-sensor-custom-intel-hinge.o
 obj-$(CONFIG_IQS624_POS)	+= iqs624-pos.o