Hi Péter,
On 3/19/24 19:02, Péter Ujfalusi wrote:
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?
In my use case, DX pin is connected to the ADC chip select pin so I want the DX pin to toggle the closest possible to capture's start. That's why I introduced this feature over configuring the pin as GPO.
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
Best regards, Bastien