dt-bindings:iio:accel:bosch,bma220 device tree binding documentation

Linux driver currently relies on the driver.name to match to the
compatible, but that doesn't mean it isn't a good idea to document it.

Only real complexity is the 3 separate power supplies.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210401174112.320497-3-jic23@kernel.org

Documentation/devicetree/bindings/iio/accel/bosch,bma220.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/accel/bosch,bma220.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Bosch BMA220 Trixial Acceleration Sensor
+
+maintainers:
+  - Jonathan Cameron <Jonathan.Cameron@huawei.com>
+
+properties:
+  compatible:
+    enum:
+      - bosch,bma220
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  spi-max-frequency: true
+
+  vdda-supply: true
+  vddd-supply: true
+  vddio-supply: true
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        accelerometer@0 {
+            compatible = "bosch,bma220";
+            reg = <0>;
+            spi-max-frequency = <2500000>;
+            interrupt-parent = <&gpio0>;
+            interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;
+        };
+    };
+...