[PATCHv4 9/9] ASoC: dt-bindings: fsl-asoc-card: add compatible for generic codec

[Elinor Montmasson <elinor.montmasson@xxxxxxxxxxxxxxxxxxxx>]

Add documentation about new dts bindings following new support
for compatible "fsl,imx-audio-generic".

Some CPU DAI don't require a real audio codec. The new compatible
"fsl,imx-audio-generic" allows using the driver with codec drivers
SPDIF DIT and SPDIF DIR as dummy codecs.
It also allows using not pre-configured audio codecs which
don't require specific control through a codec driver.

The new dts properties give the possibility to set some parameters
about the CPU DAI usually set through the codec configuration.

Signed-off-by: Elinor Montmasson <elinor.montmasson@xxxxxxxxxxxxxxxxxxxx>
---
 .../bindings/sound/fsl-asoc-card.yaml         | 96 ++++++++++++++++++-
 1 file changed, 92 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml b/Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml
index 9922664d5ccc..332d8bf96e06 100644
--- a/Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml
+++ b/Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml
@@ -23,6 +23,16 @@ description:
   and PCM DAI formats. However, it'll be also possible to support those non
   AC'97/I2S/PCM type sound cards, such as S/PDIF audio and HDMI audio, as
   long as the driver has been properly upgraded.
+  To use CPU DAIs that do not require a codec such as an S/PDIF controller,
+  or to use a DAI to output or capture raw I2S/TDM data, you can
+  use the compatible "fsl,imx-audio-generic".
+
+definitions:
+  imx-audio-generic-dependency:
+    properties:
+      compatible:
+        contains:
+          const: fsl,imx-audio-generic
 
 maintainers:
   - Shengjiu Wang <shengjiu.wang@xxxxxxx>
@@ -81,6 +91,7 @@ properties:
               - fsl,imx-audio-wm8960
               - fsl,imx-audio-wm8962
               - fsl,imx-audio-wm8958
+              - fsl,imx-audio-generic
 
   model:
     $ref: /schemas/types.yaml#/definitions/string
@@ -93,8 +104,14 @@ properties:
       need to add ASRC support via DPCM.
 
   audio-codec:
-    $ref: /schemas/types.yaml#/definitions/phandle
-    description: The phandle of an audio codec
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    description: |
+      The phandle of an audio codec.
+      If using the "fsl,imx-audio-generic" compatible, give instead a pair of
+      phandles with the spdif_transmitter first (driver SPDIF DIT) and the
+      spdif_receiver second (driver SPDIF DIR).
+    items:
+      maxItems: 1
 
   audio-cpu:
     $ref: /schemas/types.yaml#/definitions/phandle
@@ -150,8 +167,8 @@ properties:
     description: dai-link uses bit clock inversion.
 
   mclk-id:
-    $ref: /schemas/types.yaml#/definitions/uint32
-    description: main clock id, specific for each card configuration.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description: Main clock id for each codec, specific for each card configuration.
 
   mux-int-port:
     $ref: /schemas/types.yaml#/definitions/uint32
@@ -167,10 +184,68 @@ properties:
     $ref: /schemas/types.yaml#/definitions/phandle
     description: The phandle of an CPU DAI controller
 
+  # Properties relevant only with "fsl,imx-audio-generic" compatible
+  dai-tdm-slot-width:
+    description: See tdm-slot.txt.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  dai-tdm-slot-num:
+    description: See tdm-slot.txt.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  clocks:
+    description: |
+      The CPU DAI system clock, used to retrieve
+      the CPU DAI system clock frequency with the generic codec.
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: cpu_sysclk
+
+  cpu-system-clock-direction-out:
+    description: |
+      Specifies cpu system clock direction as 'out' on initialization.
+      If not set, direction is 'in'.
+    $ref: /schemas/types.yaml#/definitions/flag
+
+dependencies:
+  dai-tdm-slot-width:
+    $ref: "#/definitions/imx-audio-generic-dependency"
+  dai-tdm-slot-num:
+    $ref: "#/definitions/imx-audio-generic-dependency"
+  clocks:
+    $ref: "#/definitions/imx-audio-generic-dependency"
+  cpu-system-clock-direction-out:
+    $ref: "#/definitions/imx-audio-generic-dependency"
+
 required:
   - compatible
   - model
 
+allOf:
+  - if:
+      $ref: "#/definitions/imx-audio-generic-dependency"
+    then:
+      properties:
+        audio-codec:
+          items:
+            - description: SPDIF DIT phandle
+            - description: SPDIF DIR phandle
+        mclk-id:
+          maxItems: 1
+          items:
+            minItems: 1
+            maxItems: 2
+    else:
+      properties:
+        audio-codec:
+          maxItems: 1
+        mclk-id:
+          maxItems: 1
+          items:
+            maxItems: 1
+
 unevaluatedProperties: false
 
 examples:
@@ -195,3 +270,16 @@ examples:
              "AIN2L", "Line In Jack",
              "AIN2R", "Line In Jack";
     };
+
+  - |
+    #include <dt-bindings/clock/imx8mn-clock.h>
+    sound-spdif-asrc {
+      compatible = "fsl,imx-audio-generic";
+      model = "spdif-asrc-audio";
+      audio-cpu = <&spdif>;
+      audio-asrc = <&easrc>;
+      audio-codec = <&spdifdit>, <&spdifdir>;
+      clocks = <&clk IMX8MN_CLK_SAI5_ROOT>;
+      clock-names = "cpu_sysclk";
+      cpu-system-clock-direction-out;
+    };
-- 
2.34.1