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
+ cdns,refclk-source:
+ $ref: /schemas/types.yaml#/definitions/string
+ enum:
+ - internal
+ - external
description:
- This selects if the REFCLK for RMII is provided by an external source.
- For RGMII mode this selects if the 125MHz REF clock is provided by an external
- source.
+ Select whether or not the refclk for RGMII or RMII is provided by an
+ internal or external source. The default is device specific.
cdns,rx-watermark:
$ref: /schemas/types.yaml#/definitions/uint32
@@ -196,6 +198,33 @@ allOf:
required:
- phys
+ - if:
+ not:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - microchip,sama7g5-gem
+ - microchip,sama7g5-emac
+ then:
+ properties:
+ cdns,refclk-source: false
+
+ - if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - microchip,sama7g5-emac
+ then:
+ properties:
+ cdns,refclk-source:
+ default: external
+ else:
+ properties:
+ cdns,refclk-source:
+ default: internal
+
unevaluatedProperties: false
examples:
--
2.51.0On 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. > + cdns,refclk-source: > + $ref: /schemas/types.yaml#/definitions/string > + enum: > + - internal > + - external > description: > - This selects if the REFCLK for RMII is provided by an external source. > - For RGMII mode this selects if the 125MHz REF clock is provided by an external > - source. > + Select whether or not the refclk for RGMII or RMII is provided by an > + internal or external source. The default is device specific. Best regards, Krzysztof
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 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! > > + cdns,refclk-source: > > + $ref: /schemas/types.yaml#/definitions/string > > + enum: > > + - internal > > + - external > > description: > > - This selects if the REFCLK for RMII is provided by an external source. > > - For RGMII mode this selects if the 125MHz REF clock is provided by an external > > - source. > > + Select whether or not the refclk for RGMII or RMII is provided by an > > + internal or external source. The default is device specific. > > Best regards, > Krzysztof >
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
On Wed, Mar 11, 2026 at 07:10:09PM +0100, Krzysztof Kozlowski wrote: > 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. Right that's something I should have considered. I'll keep it so. > > 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? Nah, it's not an NOP. Commit message maybe reads that way because I was trying to avoid mentioning the driver implementation details. I think I could do a better job talking about sama7g5-emac versus sama7g5-gem in the commit message, which would show that the current property has a use case, just not as broad as it was intended to be. The existing property was added along with a driver change that modified sama7g5-emac which had a default of external to default to internal instead, and the property could be used to switch to external. sama7g5-gem had a default of internal, so this change was done to make things uniform and allow a single property to work for both devices. That driver change was reverted to maintain backwards compatibility, so the property became useless on sama7g5-emac, and there's currently no way to make that device use an internal reference. What I am doing here is probably what cdns,refclk-ext should have been originally, but when the driver's defaults got reverted the whole series probably should have been reverted so that Ryan could try again with a new approach. Instead, the property went into a release but only works on sama7g5-gem.
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