From: Daniel Baluta <daniel.baluta@nxp.com>

Document new playback-only and capture-only flags which can be used when
dai link can only support just one direction: playback or capture but
not both.

Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
---
 Documentation/devicetree/bindings/sound/simple-card.yaml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/simple-card.yaml b/Documentation/devicetree/bindings/sound/simple-card.yaml
index 59ac2d1d1ccf..1bf331f095a4 100644
--- a/Documentation/devicetree/bindings/sound/simple-card.yaml
+++ b/Documentation/devicetree/bindings/sound/simple-card.yaml
@@ -27,6 +27,14 @@ definitions:
     description: dai-link uses bit clock inversion
     $ref: /schemas/types.yaml#/definitions/flag
 
+  playback-only:
+    description: dai-link is used only for playback
+    $ref: /schemas/types.yaml#/definitions/flag
+
+  capture-only:
+    description: dai-link is used only for capture
+    $ref: /schemas/types.yaml#/definitions/flag
+
   dai-tdm-slot-num:
     description: see tdm-slot.txt.
     $ref: /schemas/types.yaml#/definitions/uint32
-- 
2.25.1

On Tue, Aug 01, 2023 at 11:24:33AM +0300, Daniel Baluta wrote:
> From: Daniel Baluta <daniel.baluta@nxp.com>
> 
> Document new playback-only and capture-only flags which can be used when
> dai link can only support just one direction: playback or capture but
> not both.
> 
> Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
> ---
>  Documentation/devicetree/bindings/sound/simple-card.yaml | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/sound/simple-card.yaml b/Documentation/devicetree/bindings/sound/simple-card.yaml
> index 59ac2d1d1ccf..1bf331f095a4 100644
> --- a/Documentation/devicetree/bindings/sound/simple-card.yaml
> +++ b/Documentation/devicetree/bindings/sound/simple-card.yaml
> @@ -27,6 +27,14 @@ definitions:
>      description: dai-link uses bit clock inversion
>      $ref: /schemas/types.yaml#/definitions/flag
>  
> +  playback-only:
> +    description: dai-link is used only for playback
> +    $ref: /schemas/types.yaml#/definitions/flag
> +
> +  capture-only:
> +    description: dai-link is used only for capture
> +    $ref: /schemas/types.yaml#/definitions/flag

Wouldn't this be implicit based on limitations in the either the cpu or 
codec DAI?

Rob

On Fri, Aug 11, 2023 at 01:12:36PM -0600, Rob Herring wrote:
> On Tue, Aug 01, 2023 at 11:24:33AM +0300, Daniel Baluta wrote:

> > +  playback-only:
> > +    description: dai-link is used only for playback
> > +    $ref: /schemas/types.yaml#/definitions/flag

> > +  capture-only:
> > +    description: dai-link is used only for capture
> > +    $ref: /schemas/types.yaml#/definitions/flag

> Wouldn't this be implicit based on limitations in the either the cpu or 
> codec DAI?

You can see cases where people just don't connect some of the signals
for whatever reason so even if the two devices could do bidrectional
audio the board can't, and there are also cases like the at91sam9g20ek
where the DAI is connected for bidrectional audio but there's not
actually any audio inputs you can connect (even loopbacks) for one of
the directions so it's best to just mask things out from the user.

On Tue, Aug 01, 2023 at 11:24:33AM +0300, Daniel Baluta wrote:
> From: Daniel Baluta <daniel.baluta@nxp.com>
> 
> Document new playback-only and capture-only flags which can be used when
> dai link can only support just one direction: playback or capture but
> not both.
> 
> Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
> ---
>  Documentation/devicetree/bindings/sound/simple-card.yaml | 8 ++++++++
>  1 file changed, 8 insertions(+)

Please add new features to audio-graph-card2 - we're trying to deprecate
simple-card, audio-graph-card2 is a superset with more flexibility.
It's not the end of the world to also support things in simple-card but
it definitely shouldn't have any capabilities that the newer card lacks.