dt-bindings: iio: adc: Add binding documentation for NXP IMX8QXP ADC

The NXP i.MX 8QuadXPlus SOC a new ADC IP, so add
binding documentation for NXP IMX8QXP ADC.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Link: https://lore.kernel.org/r/20210925020555.129-3-caihuoqing@baidu.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/nxp,imx8qxp-adc.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/nxp,imx8qxp-adc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP IMX8QXP ADC bindings
+
+maintainers:
+  - Cai Huoqing <caihuoqing@baidu.com>
+
+description:
+  Supports the ADC found on the IMX8QXP SoC.
+
+properties:
+  compatible:
+    const: nxp,imx8qxp-adc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 2
+
+  clock-names:
+    items:
+      - const: per
+      - const: ipg
+
+  assigned-clocks:
+    maxItems: 1
+
+  assigned-clock-rates:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  "#io-channel-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - assigned-clocks
+  - assigned-clock-rates
+  - power-domains
+  - "#io-channel-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/firmware/imx/rsrc.h>
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+        adc@5a880000 {
+            compatible = "nxp,imx8qxp-adc";
+            reg = <0x0 0x5a880000 0x0 0x10000>;
+            interrupts = <GIC_SPI 240 IRQ_TYPE_LEVEL_HIGH>;
+            clocks = <&clk IMX_SC_R_ADC_0>,
+                     <&clk IMX_SC_R_ADC_0>;
+            clock-names = "per", "ipg";
+            assigned-clocks = <&clk IMX_SC_R_ADC_0>;
+            assigned-clock-rates = <24000000>;
+            power-domains = <&pd IMX_SC_R_ADC_0>;
+            #io-channel-cells = <1>;
+        };
+    };
+...