ASoC: dt-bindings: davinci-mcbsp: Add the 'ti,T1-framing-{rx/tx}' flags

McBSP's data delay can be configured from 0 to 2 bit clock periods. 0 is
used for DSP_B format, 1 for DSP_A format. A data delay of 2 bit clock
periods can be used to interface to 'T1 framing' devices where data
stream is preceded by a 'framing bit'. This 2 bit clock data delay is
not described in the bindings.

Add two flags 'ti,T1-framing-[rx/tx]' to enable a data delay of 2
bit clock periods in reception or transmission.
Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Link: https://msgid.link/r/20240402071213.11671-13-bastien.curutchet@bootlin.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/davinci-mcbsp.yaml

@@ -67,6 +67,20 @@ properties:
   "#sound-dai-cells":
     const: 0
 
+  ti,T1-framing-tx:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      If the property is present, tx data delay is set to 2 bit clock periods.
+      McBSP will insert a blank period (high-impedance period) before the first
+      data bit. This can be used to interface to T1-framing devices.
+
+  ti,T1-framing-rx:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      If the property is present, rx data delay is set to 2 bit clock periods.
+      McBSP will discard the bit preceding the data stream (called framing bit).
+      This can be used to interface to T1-framing devices.
+
 required:
   - "#sound-dai-cells"
   - compatible