dt-bindings: iio: adc: add TI LMP92064 controller

Add binding documentation for the TI LMP92064 dual channel SPI ADC.
Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221128133503.1355898-1-l.goehrs@pengutronix.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/ti,lmp92064.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,lmp92064.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments LMP92064 Precision Current and Voltage Sensor.
+
+maintainers:
+  - Leonard Göhrs <l.goehrs@pengutronix.de>
+
+description: |
+  The LMP92064 is a two channel ADC intended for combined voltage and current
+  measurements.
+
+  The device contains two ADCs to allow simultaneous sampling of voltage and
+  current and thus of instantaneous power consumption.
+
+properties:
+  compatible:
+    enum:
+      - ti,lmp92064
+
+  reg:
+    maxItems: 1
+
+  vdd-supply:
+    description: Regulator that provides power to the main part of the chip
+
+  vdig-supply:
+    description: |
+      Regulator that provides power to the digital I/O part of the chip
+
+  shunt-resistor-micro-ohms:
+    description: |
+      Value of the shunt resistor (in µΩ) connected between INCP and INCN,
+      across which current is measured. Used to provide correct scaling of the
+      raw ADC measurement.
+
+  reset-gpios:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - shunt-resistor-micro-ohms
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0 {
+            compatible = "ti,lmp92064";
+            reg = <0>;
+            vdd-supply = <&vdd>;
+            vdig-supply = <&vdd>;
+            spi-max-frequency = <20000000>;
+            shunt-resistor-micro-ohms = <15000>;
+            reset-gpios = <&gpio1 16 GPIO_ACTIVE_HIGH>;
+        };
+    };
+...