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

Lukasz Majewski
2025-05-15T08:47:26Z

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Hi Rob,

Thanks for your detailed explanation.

> 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
>

So after your suggestions - I've add:

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

In the top level of the file - above of
properties:
...
ethernet-ports:
type: object
additionalProperties: true

patternProperties:
'^ethernet-port@[12]$':
type:·object
additionalProperties:·true
properties:
reg:
items:
- enum: [1, 2]
description: MTIP L2 switch port number

And after calling:
make dt_binding_check DT_SCHEMA_FILES=nxp,imx28-mtip-switch.yaml

there are no errors.

However, when I make a mistake nad in the "examples" section I change
'lablel' -> 'labelx' I see

switch@800f0000: ethernet-ports:ethernet-port@2: Unevaluated properties
are not allowed ('labelx' was unexpected)

which I suppose is expected behaviour.

>
> >
> > 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.

Best regards,

Lukasz Majewski

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