dt-bindings: iio: imu: add fxos8700 imu binding

This adds documentation for the Freescale FXOS8700 Inertial Measurement Unit
device-tree bindings.
Signed-off-by: Robert Jones <rjones@gateworks.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/imu/nxp,fxos8700.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/imu/nxp,fxos8700.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale FXOS8700 Inertial Measurement Unit
+
+maintainers:
+  - Robert Jones <rjones@gateworks.com>
+
+description: |
+  Accelerometer and magnetometer combo device with an i2c and SPI interface.
+  https://www.nxp.com/products/sensors/motion-sensors/6-axis/digital-motion-sensor-3d-accelerometer-2g-4g-8g-plus-3d-magnetometer:FXOS8700CQ
+
+properties:
+  compatible:
+    enum:
+      - nxp,fxos8700
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 1
+    maxItems: 2
+
+  interrupt-names:
+    minItems: 1
+    maxItems: 2
+    items:
+      enum:
+        - INT1
+        - INT2
+
+  drive-open-drain:
+    type: boolean
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        fxos8700@1e {
+          compatible = "nxp,fxos8700";
+          reg = <0x1e>;
+
+          interrupt-parent = <&gpio2>;
+          interrupts = <7 IRQ_TYPE_EDGE_RISING>;
+          interrupt-names = "INT1";
+        };
+    };
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        fxos8700@0 {
+          compatible = "nxp,fxos8700";
+          reg = <0>;
+
+          spi-max-frequency = <1000000>;
+          interrupt-parent = <&gpio1>;
+          interrupts = <7 IRQ_TYPE_EDGE_RISING>;
+          interrupt-names = "INT2";
+        };
+    };