[RFC PATCH net-next 2/9] dt-bindings: net: ethernet-controller: add slow-to-probe

[Aleksei Sviridkin <f@lex.la>]

A port can reference a PHY whose driver is not usable at connect
time because the PHY's firmware, or the module carrying its driver,
lives in a filesystem that is not mounted yet when the controller
probes. Today such a port is dropped at setup and stays unusable
for the whole uptime even though the PHY becomes fully functional
seconds later.

Add a boolean the port node can carry to declare this expected:
the connect keeps the port and attaches the PHY once it becomes
usable instead of failing.

The name and the schema home are an open question of this series:
the property is generic and read from the MAC/port node, so it
lands here rather than in a vendor binding, but a better-scoped
name may exist.

Assisted-by: LLM
Signed-off-by: Aleksei Sviridkin <f@lex.la>
---
 .../devicetree/bindings/net/ethernet-controller.yaml     | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
index 1bafd687dcb1..ca82672b6cb3 100644
--- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
@@ -113,6 +113,15 @@ properties:
     description:
       Specifies a reference to a node representing an IEEE 1588 PTP device.
 
+  slow-to-probe:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The PHY referenced by phy-handle may not exist, or may not have a
+      usable driver, when this controller connects to it, because the
+      driver or firmware arrives later (for example from a filesystem
+      mounted after the controller probed). Instead of failing, keep
+      the port and connect the PHY once it becomes usable.
+
   rx-fifo-depth:
     $ref: /schemas/types.yaml#/definitions/uint32
     description:
-- 
2.53.0