dt-bindings: iio: Add bindings for sx9310 sensor

Adds device tree bindings for sx9310 sensor.
Signed-off-by: Daniel Campello <campello@chromium.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: Rob Herring <robh+dt@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
[swboyd@chromium.org: Add both regulators and make them optional]
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/proximity/semtech,sx9310.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/proximity/semtech,sx9310.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Semtech's SX9310 capacitive proximity sensor
+
+maintainers:
+  - Daniel Campello <campello@chromium.org>
+
+description: |
+  Semtech's SX9310/SX9311 capacitive proximity/button solution.
+
+  Specifications about the devices can be found at:
+  https://www.semtech.com/products/smart-sensing/sar-sensors/sx9310
+
+properties:
+  compatible:
+    enum:
+      - semtech,sx9310
+      - semtech,sx9311
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description:
+      The sole interrupt generated by the device used to announce the
+      preceding reading request has finished and that data is
+      available or that a close/far proximity event has happened.
+    maxItems: 1
+
+  vdd-supply:
+    description: Main power supply
+
+  svdd-supply:
+    description: Host interface power supply
+
+  "#io-channel-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - "#io-channel-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      proximity@28 {
+        compatible = "semtech,sx9310";
+        reg = <0x28>;
+        interrupt-parent = <&pio>;
+        interrupts = <5 IRQ_TYPE_LEVEL_LOW 5>;
+        vdd-supply = <&pp3300_a>;
+        svdd-supply = <&pp1800_prox>;
+        #io-channel-cells = <1>;
+      };
+    };