On 15/03/2024 13:27, Bastien Curutchet wrote: > McBSP is able to handle capture and playback stream. > The McBSP's DX pins that outputs serial data during playback streams can > be used to output a chosen pattern during capture streams. For instance, > this can be useful to drive an active-low signal during capture streams > (by choosing <0> as pattern) or configure the MCBSPx.DX pin as GPO and use it as a GPIO? Quite novel use of the hardware, no doubt about it. If you don't have DMA servicing the TX, it will just re-transmit the word from from the DXR register when the transmitter is pulled out of reset. Interesting, but I'm not sure if this belongs to DT. > Add a 'ti,drive-dx' property that can be used to repeatedly output a > chosen pattern on DX pin while capture stream is ON. > > Signed-off-by: Bastien Curutchet <bastien.curutchet@xxxxxxxxxxx> > --- > Documentation/devicetree/bindings/sound/davinci-mcbsp.yaml | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/Documentation/devicetree/bindings/sound/davinci-mcbsp.yaml b/Documentation/devicetree/bindings/sound/davinci-mcbsp.yaml > index d8d4e7ea6e02..f4d1fc6bcd61 100644 > --- a/Documentation/devicetree/bindings/sound/davinci-mcbsp.yaml > +++ b/Documentation/devicetree/bindings/sound/davinci-mcbsp.yaml > @@ -80,6 +80,13 @@ properties: > Enable synchronisation error detections when an unexpected frame pulse is > received. If not present, unexpected frame pulses are ignored. > > + ti,drive-dx: > + $ref: /schemas/types.yaml#/definitions/uint32 > + description: > + If the property is present, McBSP will repeatedly output the selected > + value on DX pin during capture streams. For instance, if set to 0, this > + can be used to drive an active-low signal. > + > required: > - "#sound-dai-cells" > - compatible -- Péter
