[RFC PATCH net-next 1/2] dt-bindings: net: ethernet-controller: add phy-needs-host-firmware

[Aleksei Sviridkin <f@lex.la>]

A port can reference a PHY that cannot be identified or driven when
the controller connects to it, because the firmware the chip needs is
not in hand yet. Such a port is dropped at setup and stays unusable for
the whole uptime, even though the PHY works seconds later.

The flag declares that the PHY behind phy-handle is expected to become
usable only after this controller has probed. A consumer that sees it
keeps the port and connects the PHY once its driver binds, instead of
failing the connect. The prefix names the entity, like the other
properties here that name what they describe rather than the
controller; a PCS needing firmware would get pcs-needs-host-firmware
by the same rule.

It sits on the controller here because that is where the waiting
happens. The flag says nothing without a phy-handle to qualify, so it
depends on one; the deprecated phy and phy-device spellings are left
out, since no tree combines them with a property this new.

Assisted-by: LLM
Signed-off-by: Aleksei Sviridkin <f@lex.la>
---
 .../devicetree/bindings/net/ethernet-controller.yaml      | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
index 1bafd687dcb1..074c54fa6d78 100644
--- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
@@ -108,6 +108,13 @@ properties:
     $ref: "#/properties/phy-handle"
     deprecated: true
 
+  phy-needs-host-firmware:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The PHY referenced by phy-handle runs firmware that the host must
+      load before the PHY can be driven, and so is not usable for as
+      long as that has not happened.
+
   ptp-timer:
     $ref: /schemas/types.yaml#/definitions/phandle
     description:
@@ -240,6 +247,7 @@ properties:
 
 dependencies:
   pcs-handle-names: [pcs-handle]
+  phy-needs-host-firmware: [phy-handle]
 
 allOf:
   - $ref: /schemas/net/network-class.yaml#
-- 
2.53.0