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/memory-controllers/qca,ath79-ddr-controller.yaml

@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/qca,ath79-ddr-controller.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Atheros AR7xxx/AR9xxx DDR controller
+
+maintainers:
+  - Krzysztof Kozlowski <krzk@kernel.org>
+
+description: |
+  The DDR controller of the AR7xxx and AR9xxx families provides an interface to
+  flush the FIFO between various devices and the DDR. This is mainly used by
+  the IRQ controller to flush the FIFO before running the interrupt handler of
+  such devices.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: qca,ar9132-ddr-controller
+          - const: qca,ar7240-ddr-controller
+      - items:
+          - enum:
+              - qca,ar7100-ddr-controller
+              - qca,ar7240-ddr-controller
+
+  "#qca,ddr-wb-channel-cells":
+    description: |
+      Specifies the number of cells needed to encode the write buffer channel
+      index.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 1
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - "#qca,ddr-wb-channel-cells"
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    ddr_ctrl: memory-controller@18000000 {
+        compatible = "qca,ar9132-ddr-controller",
+                     "qca,ar7240-ddr-controller";
+        reg = <0x18000000 0x100>;
+
+        #qca,ddr-wb-channel-cells = <1>;
+    };
+
+    interrupt-controller {
+        // ...
+        qca,ddr-wb-channel-interrupts = <2>, <3>, <4>, <5>;
+        qca,ddr-wb-channels = <&ddr_ctrl 3>, <&ddr_ctrl 2>,
+                              <&ddr_ctrl 0>, <&ddr_ctrl 1>;
+    };