Re: [PATCH net-next v3 03/10] dt-bindings: net: cdns,macb: replace cdns,refclk-ext with cdns,refclk-source

[Krzysztof Kozlowski <krzk@kernel.org>]

On 11/03/2026 19:08, Conor Dooley wrote:
> On Wed, Mar 11, 2026 at 08:00:54AM +0100, Krzysztof Kozlowski wrote:
>> On Tue, Mar 10, 2026 at 05:17:10PM +0000, Conor Dooley wrote:
>>> From: Conor Dooley <conor.dooley@microchip.com>
>>>
>>> Ryan added cdns,refclk-ext with the intent of decoupling the source of
>>> the reference clock on sama7g5 (and related platforms) from the
>>> compatible. Unfortunately, the default for sama7g5-emac is an external
>>> reference clock, so this property had no effect there, so that
>>> compatibility with older devicetrees is preserved.
>>> Replace cdns,refclk-ext with one that supports both default states and
>>> therefore is usable for sama7g5-emac.
>>>
>>> For now, limit it to only the platforms that have USRIO controlled
>>> reference clock selection, but this could be generalised in the future.
>>>
>>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>>> ---
>>>  .../devicetree/bindings/net/cdns,macb.yaml    | 39 ++++++++++++++++---
>>>  1 file changed, 34 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/net/cdns,macb.yaml b/Documentation/devicetree/bindings/net/cdns,macb.yaml
>>> index cb14c35ba9969..a492357570edd 100644
>>> --- a/Documentation/devicetree/bindings/net/cdns,macb.yaml
>>> +++ b/Documentation/devicetree/bindings/net/cdns,macb.yaml
>>> @@ -120,12 +120,14 @@ properties:
>>>    power-domains:
>>>      maxItems: 1
>>>  
>>> -  cdns,refclk-ext:
>>> -    type: boolean
>>
>> This is already an implemented ABI, so you cannot drop it even if some
>> devices works fine on default. Instead please deprecate it and keep
>> drivers backwards compatible for whoever is using it.
> 
> The driver still will support it for those devices, but I don't see any
> value in keeping the property about, even deprecated, when it doesn't
> work properly. If you insist that it be kept and marked deprecated, it

There cannot be an undocumented ABI, so if driver has it, it must stay
in the bindings.

> needs conditional rules to only permit it on devices that it actually
> does something. I'm surprised you even considered that I would drop
> support for it from the driver!

Commit msg suggested it is no-op, thus could be dropped without having
impact?

Best regards,
Krzysztof