[RFC PATCH v2 21/22] ASoC: dt-bindings: Add Q6USB backend bindings

[Wesley Cheng <quic_wcheng@quicinc.com>]

Add a dt-binding to describe the definition of enabling the Q6 USB backend
device for audio offloading.  The node carries information, which is passed
along to the QC USB SND class driver counterpart.  These parameters will be
utilized during QMI stream enable requests.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
---
 .../bindings/sound/qcom,q6usb-dais.yaml       | 55 +++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml

diff --git a/Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml b/Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml
new file mode 100644
index 000000000000..e24b4d52fa7e
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/qcom,q6usb-dais.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm ASoC USB backend DAI
+
+maintainers:
+  - Wesley Cheng <quic_wcheng@quicinc.com>
+
+description:
+  The Q6USB backend is a supported AFE port on the Q6DSP. This backend
+  driver will communicate the required settings to the QC USB SND class
+  driver for properly enabling the audio stream.  Parameters defined
+  under this node will carry settings, which will be passed along during
+  the QMI stream enable request.
+
+properties:
+  compatible:
+    enum:
+      - qcom,q6usb-dais
+
+  iommus:
+    maxItems: 1
+
+  "#sound-dai-cells":
+    const: 1
+
+  qcom,usb-audio-stream-id:
+    description:
+      SID for the Q6DSP processor for IOMMU mapping.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  qcom,usb-audio-intr-num:
+    description:
+      Desired XHCI interrupter number to use.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+required:
+  - compatible
+  - '#sound-dai-cells'
+  - qcom,usb-audio-intr-num
+
+additionalProperties: false
+
+examples:
+  - |
+    usbdai: usbd {
+      compatible = "qcom,q6usb-dais";
+      #sound-dai-cells = <1>;
+      iommus = <&apps_smmu 0x180f 0x0>;
+      qcom,usb-audio-stream-id = <0xf>;
+      qcom,usb-audio-intr-num = <2>;
+    };