[PATCH v2 3/7] ASoC: dt-bindings: add TDM slot idle mode properties

[Rob Herring]

On Sun, Dec 21, 2025 at 07:35:59PM +1000, James Calligeros wrote:
> Add properties to describe TDM slot idle behaviour. These properties can
> be used to describe how a DAI is supposed to behave when not active.
> 
> For example, Apple Silicon laptops split a single I2S bus between two
> physical lines which are combined at an OR gate in front of the
> receiving port. One codec on each line is expected to transmit zeroes
> during the active TDM slots of the opposite line, or we will have corrupted
> data at the receiver.
> 
> Signed-off-by: James Calligeros <jcalligeros99 at gmail.com>
> ---
>  .../bindings/sound/tdm-slot.yaml         | 33 +++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/sound/tdm-slot.yaml b/Documentation/devicetree/bindings/sound/tdm-slot.yaml
> index 5bc46048d689..e8b2d35a7c37 100644
> --- a/Documentation/devicetree/bindings/sound/tdm-slot.yaml
> +++ b/Documentation/devicetree/bindings/sound/tdm-slot.yaml
> @@ -33,6 +33,17 @@ $defs:
>      $ref: /schemas/types.yaml#/definitions/uint32-array
>      description: Receive direction slot mask. Optional. Identical to TX mask.
>  
> +  dai-tdm-idle-mode:
> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum:
> +      - none
> +      - off
> +      - zero
> +      - pulldown
> +      - hiz
> +      - pullup
> +      - drivehigh
> +
>  properties:
>    dai-tdm-slot-num:
>      $ref: "#/$defs/dai-tdm-slot-num"
> @@ -46,4 +57,26 @@ properties:
>    dai-tdm-slot-rx-mask:
>      $ref: "#/$defs/dai-tdm-slot-rx-mask"
>  
> +  dai-tdm-slot-tx-idle-mode:
> +    $ref: "#/$defs/dai-tdm-idle-mode"
> +    description: Transmit direction idle slot mode. Optional. For hardware
> +      that can configure its behaviour during idle TDM slots via
> +      .set_tdm_idle(). "None" represents UB/unspecified behaviour and is the
> +      same as not setting this property.
> +
> +  dai-tdm-slot-rx-idle-mode:
> +    $ref: "#/$defs/dai-tdm-idle-mode"
> +    description: Receive direction idle slot mode. Optional. Identical to TX
> +      idle slot mode.
> +
> +  dai-tdm-slot-tx-idle-mask:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: Transmit direction idle slot mask. Optional. 1 represents
> +      an idle slot.
> +
> +  dai-tdm-slot-rx-idle-mask:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: Receive direction idle slot mask. Optional. Identical to
> +      TX mask.

These can be under a patternProperties:

patternProperties:
  '^dai-tdm-slot-[rt]x-idle-mode$':
    ...

  '^dai-tdm-slot-[rt]x-idle-mask$':
    ...

And then remove the $defs.

Rob