RE: [PATCH v5 2/5] net: macb: add support for sgmii MAC-PHY interface

[Parshuram Raju Thombare]

>> >In which case, gem_phylink_validate() must clear the support mask when
>> >SGMII mode is requested to indicate that the interface mode is not
>> >supported.
>> >The same goes for _all_ other PHY link modes that the hardware does not
>> >actually support, such as PHY_INTERFACE_MODE_10GKR...
>> If interface is not supported by hardware probe returns with error, so we don't
>> net interface is not registered at all.
>That does not negate my comment above.
Sorry if I misunderstood your question, but hardware supports interfaces and based
on that link modes are supported. So if interface is not supported by hardware,
net device is not registered and there will be no phylink_validate call.
If hardware support particular interface, link modes supported by interface
are added to (not cleared from) supported mask, provided configs is not trying to limit 
data rate using GIGABIT_ENABLE* macro.

Regards,
Parshuram Thombare