ASoC: dt-bindings: fsl_rpmsg: Add a property to assign the rpmsg channel

Add a string property to assign the rpmsg channel this sound card sits
on. This property can be omitted if there is only one sound card and it
sits on "rpmsg-audio-channel".
Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220930064441.2548505-2-chancel.liu@nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml

@@ -11,8 +11,11 @@ maintainers:
 
 description: |
   fsl_rpmsg is a virtual audio device. Mapping to real hardware devices
-  are SAI, DMA controlled by Cortex M core. What we see from Linux
-  side is a device which provides audio service by rpmsg channel.
+  are SAI, MICFIL, DMA controlled by Cortex M core. What we see from
+  Linux side is a device which provides audio service by rpmsg channel.
+  We can create different sound cards which access different hardwares
+  such as SAI, MICFIL, .etc through building rpmsg channels between
+  Cortex-A and Cortex-M.
 
 properties:
   compatible:
@@ -85,6 +88,16 @@ properties:
       This is a boolean property. If present, the receiving function
       will be enabled.
 
+  fsl,rpmsg-channel-name:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: |
+      A string property to assign rpmsg channel this sound card sits on.
+      This property can be omitted if there is only one sound card and it sits
+      on "rpmsg-audio-channel".
+    enum:
+      - rpmsg-audio-channel
+      - rpmsg-micfil-channel
+
 required:
   - compatible
   - model
@@ -107,3 +120,22 @@ examples:
                  <&clk IMX8MN_AUDIO_PLL2_OUT>;
         clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
     };
+
+  - |
+    #include <dt-bindings/clock/imx8mm-clock.h>
+
+    rpmsg_micfil: audio-controller {
+        compatible = "fsl,imx8mm-rpmsg-audio";
+        model = "micfil-audio";
+        fsl,rpmsg-channel-name = "rpmsg-micfil-channel";
+        fsl,enable-lpa;
+        fsl,rpmsg-in;
+        clocks = <&clk IMX8MM_CLK_PDM_IPG>,
+                 <&clk IMX8MM_CLK_PDM_ROOT>,
+                 <&clk IMX8MM_CLK_SDMA3_ROOT>,
+                 <&clk IMX8MM_AUDIO_PLL1_OUT>,
+                 <&clk IMX8MM_AUDIO_PLL2_OUT>;
+        clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
+    };
+
+...