Re: [PATCH v7 1/7] spi: dt-bindings: Add spi-device-addr peripheral property

[David Lechner]

On 7/22/26 2:54 AM, Janani Sunil wrote:
> Some SPI devices support sharing a single chip select across multiple
> physical chips by encoding a device address in the SPI frame itself.
> Add the generic spi-device-addr property for describing these hardware
> addresses. The property is placed on the SPI peripheral node and may
> contain multiple addresses.
> 
> Signed-off-by: Janani Sunil <janani.sunil@xxxxxxxxxx>
> ---
>  Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
> index 880a9f624566..b59d047cf117 100644
> --- a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
> +++ b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
> @@ -142,6 +142,13 @@ properties:
>      minItems: 2
>      maxItems: 4
>  
> +  spi-device-addr:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    description:
> +      Device addresses used when multiple peripherals share a single chip
> +      select. The array allows one logical peripheral to comprise multiple
> +      physical devices, with one address per device.

"per physical device" for clarity.

> +
>    st,spi-midi-ns:
>      deprecated: true
>      description: |
> 

If there is nothing useful the SPI core code can do with this information,
I'm not entirely convinced that this needs to be a common property.

And this only allows for one logical device. If we wanted to treat each
address as a logical device (all with same CS), we would need #address-cells = <2>;
instead where the DT "address" is two values, the CS and the device address.

This isn't a nak or request for change - just putting my thoughts out there
to make sure we considered it thoroughly.