Re: [PATCH v2 1/3] dt-bindings: net: nfc: add st,st21nfcd

[David Heidelberg <david@ixit.cz>]

On 19/08/2026 23:09, Kristian Brox wrote:
> The ST21NFCD (e.g. Fairphone 5) speaks raw NCI on I2C. Existing
> st,st21nfcb-* and st,st21nfcc-i2c compatibles stay NDLC. Add a
> separate compatible so those boards are not switched to the wrong
> framing.

No, this is not reason why do you introduce new compatible. You do it because 
it's different HW. The fact it shares the driver is irrelevant in the dt-binding

> 
> Also document the optional SYS_CLK (clocks) and VPS_IO (vdd-io-supply)
> used on Fairphone 5, and add an I2C example.
> 
> Signed-off-by: Kristian Brox <isyourbrainfoss@proton.me>
> ---
> diff --git a/Documentation/devicetree/bindings/net/nfc/st,st-nci.yaml b/Documentation/devicetree/bindings/net/nfc/st,st-nci.yaml
> index 1dcbddb..4bdbb36 100644
> --- a/Documentation/devicetree/bindings/net/nfc/st,st-nci.yaml
> +++ b/Documentation/devicetree/bindings/net/nfc/st,st-nci.yaml
> @@ -11,10 +11,14 @@ maintainers:
>   
>   properties:
>     compatible:
> +    description: |
> +      st,st21nfcb-* and st,st21nfcc-i2c use NDLC on the wire.
> +      st,st21nfcd is ST21NFCD with raw NCI (no NDLC PCB).

I think you can omit this description completely here, but if someone had better 
idea where to put it, I'm open to it.


>       enum:
>         - st,st21nfcb-i2c
>         - st,st21nfcb-spi
>         - st,st21nfcc-i2c
> +      - st,st21nfcd
>   
>     reset-gpios:
>       description: Output GPIO pin used for resetting the controller
> @@ -36,6 +40,15 @@ properties:
>         Specifies that the uicc swp signal can be physically connected to the
>         controller
>   
> +  clocks:
> +    maxItems: 1
> +    description:
> +      External reference clock connected to SYS_CLK.
> +
> +  vdd-io-supply:
> +    description:
> +      Digital I/O supply (VPS_IO).
> +
>   required:
>     - compatible
>     - interrupts
> @@ -49,6 +62,7 @@ if:
>           enum:
>             - st,st21nfcb-i2c
>             - st,st21nfcc-i2c
> +          - st,st21nfcd
>   then:
>     properties:
>       spi-max-frequency: false
> @@ -81,6 +95,27 @@ examples:
>           };
>       };
>   
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        nfc@8 {
> +            compatible = "st,st21nfcd";
> +            reg = <0x08>;
> +
> +            interrupt-parent = <&gpio5>;
> +            interrupts = <2 IRQ_TYPE_LEVEL_HIGH>;

use interrupts extended (interrupt-parent + interrupts in one line).

As a last point (for the series), never send a new series with Reply-to (as a 
followup to existing one). It looks messy, we have tools to track series :)
see: https://patchwork.kernel.org/project/oe-linux-nfc/list/

David

> +            reset-gpios = <&gpio5 29 GPIO_ACTIVE_HIGH>;
> +
> +            clocks = <&clk>;
> +            vdd-io-supply = <&vdd_io>;
> +        };
> +    };
> +
>     - |
>       #include <dt-bindings/gpio/gpio.h>
>       #include <dt-bindings/interrupt-controller/irq.h>
>