Re: [net-next v11 1/7] dt-bindings: net: Add MTIP L2 switch description

[Rob Herring <robh@kernel.org>]

On Tue, May 13, 2025 at 08:09:20AM +0200, Lukasz Majewski wrote:
> Hi Rob,
> 
> > On Sun, May 04, 2025 at 04:55:32PM +0200, Lukasz Majewski wrote:
> > > This patch provides description of the MTIP L2 switch available in
> > > some NXP's SOCs - e.g. imx287.
> > > 
> > > Signed-off-by: Lukasz Majewski <lukma@denx.de>
> > > Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
> > > 
> > > ---
> > > Changes for v2:
> > > - Rename the file to match exactly the compatible
> > >   (nxp,imx287-mtip-switch)
> > > 
> > > Changes for v3:
> > > - Remove '-' from const:'nxp,imx287-mtip-switch'
> > > - Use '^port@[12]+$' for port patternProperties
> > > - Drop status = "okay";
> > > - Provide proper indentation for 'example' binding (replace 8
> > >   spaces with 4 spaces)
> > > - Remove smsc,disable-energy-detect; property
> > > - Remove interrupt-parent and interrupts properties as not required
> > > - Remove #address-cells and #size-cells from required properties
> > > check
> > > - remove description from reg:
> > > - Add $ref: ethernet-switch.yaml#
> > > 
> > > Changes for v4:
> > > - Use $ref: ethernet-switch.yaml#/$defs/ethernet-ports and remove
> > > already referenced properties
> > > - Rename file to nxp,imx28-mtip-switch.yaml
> > > 
> > > Changes for v5:
> > > - Provide proper description for 'ethernet-port' node
> > > 
> > > Changes for v6:
> > > - Proper usage of
> > >   $ref: ethernet-switch.yaml#/$defs/ethernet-ports/patternProperties
> > >   when specifying the 'ethernet-ports' property
> > > - Add description and check for interrupt-names property
> > > 
> > > Changes for v7:
> > > - Change switch interrupt name from 'mtipl2sw' to 'enet_switch'
> > > 
> > > Changes for v8:
> > > - None
> > > 
> > > Changes for v9:
> > > - Add GPIO_ACTIVE_LOW to reset-gpios mdio phandle
> > > 
> > > Changes for v10:
> > > - None
> > > 
> > > Changes for v11:
> > > - None
> > > ---
> > >  .../bindings/net/nxp,imx28-mtip-switch.yaml   | 149
> > > ++++++++++++++++++ 1 file changed, 149 insertions(+)
> > >  create mode 100644
> > > Documentation/devicetree/bindings/net/nxp,imx28-mtip-switch.yaml
> > > 
> > > diff --git
> > > a/Documentation/devicetree/bindings/net/nxp,imx28-mtip-switch.yaml
> > > b/Documentation/devicetree/bindings/net/nxp,imx28-mtip-switch.yaml
> > > new file mode 100644 index 000000000000..35f1fe268de7 --- /dev/null
> > > +++
> > > b/Documentation/devicetree/bindings/net/nxp,imx28-mtip-switch.yaml
> > > @@ -0,0 +1,149 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR
> > > BSD-2-Clause) +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/net/nxp,imx28-mtip-switch.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: NXP SoC Ethernet Switch Controller (L2 MoreThanIP switch)
> > > +
> > > +maintainers:
> > > +  - Lukasz Majewski <lukma@denx.de>
> > > +
> > > +description:
> > > +  The 2-port switch ethernet subsystem provides ethernet packet
> > > (L2)
> > > +  communication and can be configured as an ethernet switch. It
> > > provides the
> > > +  reduced media independent interface (RMII), the management data
> > > input
> > > +  output (MDIO) for physical layer device (PHY) management.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: nxp,imx28-mtip-switch
> > > +
> > > +  reg:
> > > +    maxItems: 1
> > > +
> > > +  phy-supply:
> > > +    description:
> > > +      Regulator that powers Ethernet PHYs.
> > > +
> > > +  clocks:
> > > +    items:
> > > +      - description: Register accessing clock
> > > +      - description: Bus access clock
> > > +      - description: Output clock for external device - e.g. PHY
> > > source clock
> > > +      - description: IEEE1588 timer clock
> > > +
> > > +  clock-names:
> > > +    items:
> > > +      - const: ipg
> > > +      - const: ahb
> > > +      - const: enet_out
> > > +      - const: ptp
> > > +
> > > +  interrupts:
> > > +    items:
> > > +      - description: Switch interrupt
> > > +      - description: ENET0 interrupt
> > > +      - description: ENET1 interrupt
> > > +
> > > +  interrupt-names:
> > > +    items:
> > > +      - const: enet_switch
> > > +      - const: enet0
> > > +      - const: enet1
> > > +
> > > +  pinctrl-names: true
> > > +
> > > +  ethernet-ports:
> > > +    type: object
> > > +    $ref:
> > > ethernet-switch.yaml#/$defs/ethernet-ports/patternProperties  
> > 
> > 'patternProperties' is wrong. Drop.
> > 
> 
> When I do drop it, then
> make dt_binding_check DT_SCHEMA_FILES=nxp,imx28-mtip-switch.yaml
> 
> shows:
> 
> nxp,imx28-mtip-switch.example.dtb: switch@800f0000: ethernet-ports:
> 'oneOf' conditional failed, one must be fixed:
> 
> 'ports' is a required property 
> 'ethernet-ports' is a required property
>         from schema $id:
>         http://devicetree.org/schemas/net/nxp,imx28-mtip-switch.yaml#

Actually, it needs to be at the top-level as well:

allOf:
  - $ref: ethernet-switch.yaml#/$defs/ethernet-ports


> 
> We do have ethernet-ports:
> and we do "include" ($ref)
> https://elixir.bootlin.com/linux/v6.14.6/source/Documentation/devicetree/bindings/net/ethernet-switch.yaml#L77
> 
> which is what we exactly need.

The $ref is effectively pasting in what you reference, so the result 
would be:

ethernet-ports:
  type: object
  "^(ethernet-)?ports$":
    patternProperties:
      "^(ethernet-)?port@[0-9a-f]+$":
        description: Ethernet switch ports
        $ref: ethernet-switch-port.yaml#
        unevaluatedProperties: false

A DT node/property name and json-schema keyword at the same level is 
never correct. json-schema behavior is to ignore (silently) any unknown 
keyword. So the validator sees the keyword "^(ethernet-)?ports$" and 
ignores everything below it.


> 
> > > +    additionalProperties: true  
> > 
> > Drop.
> > 
> 
> When removed we do have:
> nxp,imx28-mtip-switch.example.dtb: switch@800f0000: Unevaluated
> properties are not allowed ('ethernet-ports' was unexpected)
> 
> or 
> 
> nxp,imx28-mtip-switch.yaml: ethernet-ports: Missing
> additionalProperties/unevaluatedProperties constraint

'additionalProperties: true' should suppress that.

> 
> Depending if I do remove 'patternProperties' above.
> 
> To sum up - with the current code, the DT schema checks pass. It also
> looks like the $ref for ethernet-switch is used in an optimal way.
> 
> I would opt for keeping the code as is for v12.