ASoC: dt-bindings: audio-graph-port: Add dai-tdm-slot-width-map

Some audio hardware cannot support a fixed slot width for all sample
widths, or a slot width equal to the sample width for all sample widths.
This is usually due either to limitations of the audio serial port or
system clocking restrictions.

This property allows setting a mapping of sample widths and the
corresponding tdm slot widths. The slot count is also provided for
each slot width - although this would almost always be the same for
all slot widths this allows for possibly adding extra padding slots
to maintain a fixed bitclock frequency.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220228172754.453783-2-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/Documentation/devicetree/bindings/sound/audio-graph-port.yaml b/Documentation/devicetree/bindings/sound/audio-graph-port.yaml
index 476dcb4..5c36867 100644 (file)
--- a/Documentation/devicetree/bindings/sound/audio-graph-port.yaml
+++ b/Documentation/devicetree/bindings/sound/audio-graph-port.yaml
@@ -71,4 +71,24 @@ patternProperties:
         description: CPU to Codec rate channels.
         $ref: /schemas/types.yaml#/definitions/uint32
 
+      dai-tdm-slot-width-map:
+        description: Mapping of sample widths to slot widths. For hardware
+          that cannot support a fixed slot width or a slot width always
+          equal to sample width. A matrix of one or more 3-tuples.
+        $ref: /schemas/types.yaml#/definitions/uint32-matrix
+        items:
+          items:
+            -
+              description: Sample width in bits
+              minimum: 8
+              maximum: 64
+            -
+              description: Slot width in bits
+              minimum: 8
+              maximum: 256
+            -
+              description: Slot count
+              minimum: 1
+              maximum: 64
+
 additionalProperties: true