Re: [PATCH 2/4] dt-bindings: net: dsa: document internal MDIO bus

[Arınç ÜNAL]

On 13.09.2023 10:42, Vladimir Oltean wrote:
> On Wed, Sep 13, 2023 at 08:52:37AM +0300, Arınç ÜNAL wrote:
> > On 12.09.2023 22:34, Vladimir Oltean wrote:
> > > Right, it should have been anyOf and not oneOf.. my mistake. It is a bug
> > > which should be fixed. It's the same phylink that gets used in both cases,
> > > user ports and shared ports :)
> >
> > One more thing, I don't recall phy-mode being required to be defined for
> > user ports as it will default to GMII. I don't believe this is the same
> > case for shared ports so phy-mode is required only for them?
>
> phy-mode is not strictly required, but I think there is a strong
> preference to set it. IIRC, when looking at the DSA device trees, there
> was no case where phy-mode would be absent on CPU/DSA ports if the other
> link properties were also present, so we required it too. There were no
> complaints in 1 year since dsa_shared_port_validate_of() is there. The
> requirement can be relaxed to just a warning and no error in the kernel,
> and the removal of "required" in the schema, if it helps making it
> common with user ports.

I'd say no need as it doesn't make it complicated that much. See below.

> I think that the fallback to PHY_INTERFACE_MODE_GMII applies only if
> there is a phy_device (phy-handle). But otherwise, I don't remember if
> the PHY_INTERFACE_MODE_NA passed to phylink_create() will persist at
> runtime, or cause an error somewhere.
>
> > > > The phylink bindings for shared ports enforced on all switches on
> > > > dsa-port.yaml:
> > > >
> > > >     allOf:
> > > >       - required:
> > > >           - phy-mode
> > > >       - oneOf:
> > > >           - required:
> > > >               - fixed-link
> > > >           - required:
> > > >               - phy-handle
> > > >           - required:
> > > >               - managed
> > > >
> > > > Here's what I understand:
> > > >
> > > > - For switches in dsa_switches_apply_workarounds[]
> > > >     - Enforce the latter for shared ports.
> > > >     - Enforce the former for user ports.
> > > >
> > > > - For switches not in dsa_switches_apply_workarounds[]
> > > >     - Enforce the former for all ports.
> > >
> > > No, no. We enforce the dt-schema regardless of switch presence in
> > > dsa_switches_apply_workarounds[], to encourage users to fix device trees
> > > (those who run schema validation). The kernel workaround consists in
> > > doing something (skipping phylink) for the device trees where the schema
> > > warns on shared ports. But there should be a single sub-schema for
> > > validating phylink bindings, whatever port kind it is.
> >
> > Hmm, like writing phylink.yaml and then referring to it under the port
> > pattern node? This could prevent a lot of repetition.
> >
> > Arınç
>
> Yes, that would sound good.

If I understand correctly, these phylink rules are for switch ports. The
fixed-link, phy-handle, and managed properties are described on
ethernet-controller.yaml so I thought it would make sense to define the
rules there and refer to them where they're needed.

Example:

diff --git a/Documentation/devicetree/bindings/net/dsa/dsa-port.yaml b/Documentation/devicetree/bindings/net/dsa/dsa-port.yaml
index 480120469953..7279ab31aea7 100644
--- a/Documentation/devicetree/bindings/net/dsa/dsa-port.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/dsa-port.yaml
@@ -65,16 +65,8 @@ if:
     - required: [ ethernet ]
     - required: [ link ]
 then:
-  allOf:
-    - required:
-        - phy-mode
-    - oneOf:
-        - required:
-            - fixed-link
-        - required:
-            - phy-handle
-        - required:
-            - managed
+  $ref: /schemas/net/ethernet-controller.yaml#/$defs/phylink-switch
+  required: [ phy-mode ]
 
 additionalProperties: true
 
diff --git a/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml b/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
index e532c6b795f4..742aaf1a5ef2 100644
--- a/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
@@ -179,6 +179,15 @@ required:
   - compatible
   - reg
 
+if:
+  required: [ mdio ]
+then:
+  patternProperties:
+    "^(ethernet-)?ports$":
+      patternProperties:
+        "^(ethernet-)?port@[0-9]+$":
+          $ref: /schemas/net/ethernet-controller.yaml#/$defs/phylink-switch
+
 $defs:
   mt7530-dsa-port:
     patternProperties:
diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
index 9f6a5ccbcefe..d7256f33d946 100644
--- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
@@ -284,6 +284,21 @@ allOf:
             controllers that have configurable TX internal delays. If this
             property is present then the MAC applies the TX delay.
 
+$defs:
+  phylink-switch:
+    description: phylink bindings for switch ports
+    allOf:
+      - anyOf:
+          - required: [ fixed-link ]
+          - required: [ phy-handle ]
+          - required: [ managed ]
+
+      - if:
+          required: [ fixed-link ]
+        then:
+          not:
+            required: [ managed ]
+
 additionalProperties: true
 
 ...

Arınç