Re: [PATCH v4 2/9] dt-bindings: iio: adc: ad7768-1: Document multidevice support

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] dt-bindings: iio: adc: ad7768-1: missing schema constraints on spi-rx-bus-width
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commit 6ac23a15419b8807e67f7b54e0a33ca605e1e6c8
Author: Jonathan Santos <Jonathan.Santos@analog.com>

dt-bindings: iio: adc: ad7768-1: Document multidevice support

This commit updates the adi,ad7768-1 device tree binding to support
aggregating up to four devices on a single spi controller using multiple
reg entries, spi-rx-bus-width, and spi-cs-composite.

> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
> index 7b72d14e104c2..64c1cbeaa5762 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
> @@ -26,7 +26,10 @@ properties:
>        - adi,adaq7769-1
>  
>    reg:
> -    maxItems: 1
> +    minItems: 1
> +    maxItems: 4
> +    description:
> +      Chip select number. For multi-device setups, one entry per device.
>  
>    clocks:
>      maxItems: 1
> @@ -109,6 +112,12 @@ properties:
>    reset-gpios:
>      maxItems: 1
>  
> +  spi-rx-bus-width:
> +    description:
> +      Bus width per CS. For multi-device setups (multiple reg entries), one
> +      entry per device must be provided. Required when reg has more than
> +      one entry.
> +
>    spi-cpol: true
>  
>    spi-cpha: true
> @@ -203,6 +212,16 @@ allOf:
>        properties:
>          pga-gpios: false
>  
> +  # Required properties for multi-device setups
> +  - if:
> +      properties:
> +        reg:
> +          minItems: 2
> +    then:
> +      required:
> +        - spi-rx-bus-width
> +        - spi-cs-composite
> +
>  unevaluatedProperties: false

[Severity: Low]
In Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml,
properties:spi-rx-bus-width only adds a description without constraining
minItems, maxItems, or the per-item value. Because this binding references
spi-peripheral-props.yaml, spi-rx-bus-width inherits an unbounded
uint32-array allowing values from [0, 1, 2, 4, 8] even though each ad7768-1
device uses a single 1-bit data lane and at most four devices can be
aggregated.

Also, in the allOf conditional block for reg with minItems: 2, the then
branch marks spi-rx-bus-width and spi-cs-composite as required, but does
not require minItems: 2 on spi-rx-bus-width or disallow spi-cs-composite
when reg has only one entry.

If a device tree node for adi,ad7768-1 specifies multiple reg entries with
only a single spi-rx-bus-width entry, or specifies unsupported bus widths
or more than four lanes, it will pass dt_binding_check and then fail at
probe time in devm_spi_new_ancillary_device_with_lane() when rx_lane_idx >=
spi->num_rx_lanes.

Should properties:spi-rx-bus-width specify minItems: 1, maxItems: 4, and
items: const: 1 (similar to
Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml), and should the
allOf entry enforce minItems: 2 on spi-rx-bus-width when reg has
minItems: 2?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1792435248.git.Jonathan.Santos@analog.com?part=2