Re: [PATCH v2 4/8] dt-bindings: iio: dfsdm: move to backend framework

On Tue, Jun 25, 2024 at 05:07:12PM +0200, Olivier Moysan wrote:

Change the DFSDM binding to use the new IIO backend framework, along with the adoption of IIO generic channels. This binding change allows to add scaling support to the DFSDM.

Keep the legacy binding as deprecated for backward compatibility.

The io-backends property is supported only in generic IIO channel binding.

• Channel description with the generic binding (Audio and Analog):

  Properties superseded by generic properties: st,adc-channels: becomes "reg" property in channel node st,adc-channel-names: becomes "label" property in channel node Properties moved to channel child node: st,adc-channel-types: becomes st,adc-channel-type st,adc-channel-clk-src, st,adc-alt-channel

• Analog binding:

  DFSDM filter channel is configured as an IIO backend consumer. Add io-backends property in channel child nodes.

  DFSDM is no more configured as a channel consumer from SD modulator. Use of io-channels in DFSDM node is deprecated.

• Audio binding:

  DFSDM audio DAI is configured as a channel consumer from DFSDM filter. No change compare to legacy.

Signed-off-by: Olivier Moysan olivier.moysan@foss.st.com

.../bindings/iio/adc/st,stm32-dfsdm-adc.yaml | 157 +++++++++++++++++- 1 file changed, 151 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml index c1b1324fa132..1802120b16b0 100644 --- a/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml @@ -102,9 +102,11 @@ patternProperties: items: minimum: 0 maximum: 7

•    deprecated: true
  
   st,adc-channel-names:
     description: List of single-ended channel names.
  

•    deprecated: true
  
   st,filter-order:
     description: |
  

@@ -118,6 +120,12 @@ patternProperties: "#io-channel-cells": const: 1

•  '#address-cells':
  

•    const: 1
  

•  '#size-cells':
  

•    const: 0
  

•  st,adc-channel-types:
     description: |
       Single-ended channel input type.
  

@@ -128,6 +136,7 @@ patternProperties: items: enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ] $ref: /schemas/types.yaml#/definitions/non-unique-string-array

•    deprecated: true
  
   st,adc-channel-clk-src:
     description: |
  

@@ -139,6 +148,7 @@ patternProperties: items: enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ] $ref: /schemas/types.yaml#/definitions/non-unique-string-array

•    deprecated: true
  
   st,adc-alt-channel:
     description:
  

@@ -147,6 +157,7 @@ patternProperties: If not set, channel n is connected to SPI input n. If set, channel n is connected to SPI input n + 1. type: boolean

•    deprecated: true
  
   st,filter0-sync:
     description:
  

@@ -165,11 +176,64 @@ patternProperties: - compatible - reg - interrupts

•  - st,adc-channels
  

•  - st,adc-channel-names
   - st,filter-order
   - "#io-channel-cells"
  
  

• patternProperties:

•  "^channel@([0-9]|1[0-9])$":
  

Unit-addresses are normally hex. And according to reg below, the max value is 8.

•    type: object
  

•    $ref: adc.yaml
  

•    description: Represents the external channels which are connected to the DFSDM.
  

•    properties:
  

•      reg:
  

•        items:
  

•          minimum: 0
  

•          maximum: 8
  

More than 1 reg entry valid? Either way, you need maxItems. Or you can just drop 'items'

•      label:
  

•        description:
  

•          Unique name to identify which channel this is.
  

•      st,adc-channel-type:
  

•        description: |
  

•          Single-ended channel input type.
  

•          - "SPI_R": SPI with data on rising edge (default)
  

•          - "SPI_F": SPI with data on falling edge
  

•          - "MANCH_R": manchester codec, rising edge = logic 0, falling edge = logic 1
  

•          - "MANCH_F": manchester codec, rising edge = logic 1, falling edge = logic 0
  

•        items:
  

'items' is for arrays, but...

•          enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ]
  

•        $ref: /schemas/types.yaml#/definitions/string
  

not an array.

•      st,adc-channel-clk-src:
  

•        description: |
  

•          Conversion clock source.
  

•          - "CLKIN": external SPI clock (CLKIN x)
  

•          - "CLKOUT": internal SPI clock (CLKOUT) (default)
  

•          - "CLKOUT_F": internal SPI clock divided by 2 (falling edge).
  

•          - "CLKOUT_R": internal SPI clock divided by 2 (rising edge).
  

•        items:
  

ditto

•          enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ]
  

•        $ref: /schemas/types.yaml#/definitions/string
  

•      st,adc-alt-channel:
  

•        description:
  

•          Must be defined if two sigma delta modulators are
  

•          connected on same SPI input.
  

•          If not set, channel n is connected to SPI input n.
  

•          If set, channel n is connected to SPI input n + 1.
  

•        type: boolean
  

•      io-backends:
  

•        description:
  

•          Used to pipe external sigma delta modulator or internal ADC backend to DFSDM channel.
  

How many entries (maxItems)?

•    required:
  

•      - reg
  

•    additionalProperties: false
  

Put this next to the $ref for the node. And switch to unevaluatedProperties and drop 'label' from here.

• allOf: - if: properties:

@@ -199,9 +263,19 @@ patternProperties: description: From common IIO binding. Used to pipe external sigma delta modulator or internal ADC output to DFSDM channel.

•          deprecated: true
  
  

•      required:
  

•        - io-channels
  

•      if:
  

•        required:
  

•          - st,adc-channels
  

•      then:
  

•        required:
  

•          - io-channels
  

•      patternProperties:
  

•        "^channel@([0-9]|1[0-9])$":
  

•          required:
  

•            - io-backends
  

Don't think this is needed here. If channel node is present, the io-backends should always be required, right? Then this can go under the node schema.

Rob