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@bootlin.com
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 selectedvalue on DX pin during capture streams. For instance, if set to 0, thiscan be used to drive an active-low signal.required:
- "#sound-dai-cells"
- compatible