Re: [PATCH v3 net-next 12/14] dt-bindings: net: dsa: ocelot: add ocelot-ext documentation

[Vladimir Oltean <olteanv@gmail.com>]

On Mon, Oct 10, 2022 at 09:37:23AM -0400, Krzysztof Kozlowski wrote:
> What stops you from doing that? What do you need from me?

To end the discussion on a constructive note, I think if I were Colin,
I would do the following, in the following order, according to what was
expressed as a constraint:

1. Reword the "driver" word out of mscc,vsc7514-switch.yaml and express
   the description in terms of what the switch can do, not what the
   driver can do.

2. Make qca8k.yaml have "$ref: dsa.yaml#". Remove "$ref: dsa-port.yaml#"
   from the same schema.

3. Remove "- $ref: dsa-port.yaml#" from mediatek,mt7530.yaml. It doesn't
   seem to be needed, since dsa.yaml also has this. We need this because
   we want to make sure no one except dsa.yaml references dsa-port.yaml.

4. Move the DSA-unspecific portion from dsa.yaml into a new
   ethernet-switch.yaml. What remains in dsa.yaml is "dsa,member".
   The dsa.yaml schema will have "$ref: ethernet-switch.yaml#" for the
   "(ethernet-)switch" node, plus its custom additions.

5. Move the DSA-unspecific portion from dsa-port.yaml into a new
   ethernet-switch-port.yaml. What remains in dsa-port.yaml is:
   * ethernet phandle
   * link phandle
   * label property
   * dsa-tag-protocol property
   * the constraint that CPU and DSA ports must have phylink bindings

6. The ethernet-switch.yaml will have "$ref: ethernet-switch-port.yaml#"
   and "$ref: dsa-port.yaml". The dsa-port.yaml schema will *not* have
   "$ref: ethernet-switch-port.yaml#", just its custom additions.
   I'm not 100% on this, but I think there will be a problem if:
   - dsa.yaml references ethernet-switch.yaml
     - ethernet-switch.yaml references ethernet-switch-port.yaml
   - dsa.yaml also references dsa-port.yaml
     - dsa-port.yaml references ethernet-switch-port.yaml
   because ethernet-switch-port.yaml will be referenced twice. Again,
   not sure if this is a problem. If it isn't, things can be simpler,
   just make dsa-port.yaml reference ethernet-switch-port.yaml, and skip
   steps 2 and 3 since dsa-port.yaml containing just the DSA specifics
   is no longer problematic.

7. Make mscc,vsc7514-switch.yaml have "$ref: ethernet-switch.yaml#" for
   the "mscc,vsc7514-switch.yaml" compatible string. This will eliminate
   its own definitions for the generic properties: $nodename and
   ethernet-ports (~45 lines of code if I'm not mistaken).

8. Introduce the "mscc,vsc7512-switch" compatible string as part of
   mscc,vsc7514-switch.yaml, but this will have "$ref: dsa.yaml#" (this
   will have to be referenced by full path because they are in different
   folders) instead of "ethernet-switch.yaml". Doing this will include
   the common bindings for a switch, plus the DSA specifics.

9. Optional: rework ti,cpsw-switch.yaml, microchip,lan966x-switch.yaml,
   microchip,sparx5-switch.yaml to have "$ref: ethernet-switch.yaml#"
   which should reduce some duplication in existing schemas.

10. Question for future support of VSC7514 in DSA mode: how do we decide
    whether to $ref: ethernet-switch.yaml or dsa.yaml? If the parent MFD
    node has a compatible string similar to "mscc,vsc7512", then use DSA,
    otherwise use generic ethernet-switch?

Colin, how does this sound?