Re: [PATCH 1/4] dt-bindings: sound: Add simple-iio-aux

On Fri, Apr 21, 2023 at 02:41:19PM +0200, Herve Codina wrote:

Industrial I/O devices can be present in the audio path. These devices needs to be viewed as audio components in order to be fully integrated in the audio path.

simple-iio-aux allows to consider these Industrial I/O devices as auxliary audio devices.

What makes it simple? Any binding called simple or generic is a trigger for me. Best to avoid those terms. :)

Examples of devices would be useful here.

Signed-off-by: Herve Codina herve.codina@bootlin.com

.../bindings/sound/simple-iio-aux.yaml | 65 +++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 Documentation/devicetree/bindings/sound/simple-iio-aux.yaml

diff --git a/Documentation/devicetree/bindings/sound/simple-iio-aux.yaml b/Documentation/devicetree/bindings/sound/simple-iio-aux.yaml new file mode 100644 index 000000000000..fab128fce4fc --- /dev/null +++ b/Documentation/devicetree/bindings/sound/simple-iio-aux.yaml @@ -0,0 +1,65 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/sound/simple-iio-aux.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#

+title: Simple IIO auxiliary

+maintainers:

• • Herve Codina herve.codina@bootlin.com

+description: |

Don't need '|'

• Auxiliary device based on Industrial I/O device channels

+allOf:

• • $ref: /schemas/iio/iio-consumer.yaml

You don't need to reference consumer schemas.

• • $ref: dai-common.yaml#

+properties:

• compatible:
• const: simple-iio-aux
• io-channels:
• description:

•  Industrial I/O device channels used
  

• io-channel-names:
• description:

•  Industrial I/O channel names related to io-channels.
  

•  These names are used to provides sound controls, widgets and routes names.
  

• invert:

Property names should globally only have 1 type definition. This is generic enough I'd be concerned that's not the case.

• $ref: /schemas/types.yaml#/definitions/uint32-array
• description: |

•  A list of 0/1 flags defining whether or not the related channel is
  

•  inverted
  

• items:

•  enum: [0, 1]
  

•  default: 0
  

•  description: |
  

•    Invert the sound control value compared to the IIO channel raw value.
  

•      - 1: The related sound control value is inverted meaning that the
  

•           minimum sound control value correspond to the maximum IIO channel
  

•           raw value and the maximum sound control value correspond to the
  

•           minimum IIO channel raw value.
  

•      - 0: The related sound control value is not inverted meaning that the
  

•           minimum (resp maximum) sound control value correspond to the
  

•           minimum (resp maximum) IIO channel raw value.
  

+required:

• • compatible
• • io-channels
• • io-channel-names

+unevaluatedProperties: false

+examples:

• • |
• aux {

•    compatible = "simple-iio-aux";
  

•    io-channels = <&iio 0>, <&iio 1>, <&iio 2>, <&iio 3>;
  

•    io-channel-names = "CH0", "CH1", "CH2", "CH3";
  

Not really useful names. Do you have a real example?

•    /* Invert CH1 and CH2 */
  

•    invert = <0 1 1>;
  

IMO, invert should be same length as io-channels.

• };

How do support multiple instances? Say you have 2 sound cards (or 1 sound card with multiple audio paths) each with different sets of IIO channels associated with it. You'd need a link to each 'aux' node. Why not just add io-channels to the sound card nodes directly? That's already just a virtual, top-level container node grouping all the components. I don't see why we need another virtual node grouping a subset of them.

Rob