dt-bindings: Add devicetree bindings

Add snapshot of device tree bindings from keystone common kernel, branch
"android-mainline-keystone-qcom-release" at c4c12103f9c0 ("Snap for 9228065
from e32903b9a63bb558df8b803b076619c53c16baad to
android-mainline-keystone-qcom-release").

Change-Id: I7682079615cbd9f29340a5c1f2a1d84ec441a1f1
Signed-off-by: Melody Olvera <quic_molvera@quicinc.com>

bindings/iio/resolver/adi,ad2s90.yaml

@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/resolver/adi,ad2s90.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD2S90 Resolver-to-Digital Converter
+
+maintainers:
+  - Matheus Tavares <matheus.bernardino@usp.br>
+
+description: |
+  Datasheet: https://www.analog.com/en/products/ad2s90.html
+
+properties:
+  compatible:
+    const: adi,ad2s90
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 830000
+    description: |
+      Chip's max frequency, as specified in its datasheet, is 2Mhz. But a 600ns
+      delay is expected between the application of a logic LO to CS and the
+      application of SCLK, as also specified. And since the delay is not
+      implemented in the spi code, to satisfy it, SCLK's period should be at
+      most 2 * 600ns, so the max frequency should be 1 / (2 * 6e-7), which gives
+      roughly 830000Hz.
+
+  spi-cpol: true
+
+  spi-cpha: true
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+dependencies:
+  spi-cpol: [ spi-cpha ]
+  spi-cpha: [ spi-cpol ]
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        resolver@0 {
+            compatible = "adi,ad2s90";
+            reg = <0>;
+            spi-max-frequency = <830000>;
+            spi-cpol;
+            spi-cpha;
+        };
+    };
+...