Re: [PATCH v4 net-next 1/2] dt-bindings: phy: cadence-torrent: Update property values to support 3 clocks

[Gokul Praveen]

Hi Krzystof,

On 02/07/26 11:53, Krzysztof Kozlowski wrote:
> On Wed, Jul 01, 2026 at 07:54:56PM +0530, Gokul Praveen wrote:
> > Update maxItems value of "clocks" property to 3 as description of
> > this parameter already indicates 3 clocks(refclk,pll1_refclk(optional)
> > and phy_en_refclk(optional)).
> But what if description is wrong? You need to provide rationale why you
> are doing it and you cannot use existing code alone as that rationale,
> because as you pointed out - existing code is not fully correct.

The description is correct because not all device may have 2 input  
reference clocks , hence keeping the requirement of the 2nd reference 
clock(pll1_refclk) optional.

Just as a note: phy_en_refclk is an output clock.

In those cases the multilink serdes configurations requiring 2 different 
input reference clocks will not work due to the limitation of having 
only 1 clock.

However, when it comes to devices where 2 different input reference 
clocks are supported and a multilink serdes configuration is 
needed(where the links require separate reference clocks for each 
protocol so as to cater to the  different clocking speed requirements of 
these links).

Hence, in this case ,2 different input clocks are needed so as to cater 
to 2 different clock speeds.

For eg: In the USXGMII+SGMII multilink serdes configuration which I had 
tested, it failed because

USXGMII requires an input clock speed of 156.25 Mhz and SGMII protocol 
requires an input clock speed of 100 Mhz.

But, since there was only one input clock(refclk) mentioned in the 
clocks and clock-name parameter , this multilink serdes configuration 
failed.

Hence, to make it work, the pll1_refclk had to be added which provided a 
clock speed of 156.25 Mhz for USXGMI and the refclk provided

a clock speed of 100 Mhz  for SGMII.

> > Update the maxItems and items value of "clock-names" property with multiple
> > combination of clock-names possible since pll1_refclk and phy_en_refclk are
> > optional clocks.
> Why? You need to describe why you are doing this, not what you are
> doing.
Sure , Krzysztof, I will be careful about that and prioritize that in 
the commit message.
> > Signed-off-by: Gokul Praveen <g-praveen@xxxxxx>
> > ---
> >   .../bindings/phy/phy-cadence-torrent.yaml        | 16 ++++++++++++----
> >   1 file changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/phy/phy-cadence-torrent.yaml b/Documentation/devicetree/bindings/phy/phy-cadence-torrent.yaml
> > index 9af39b33646a..96c664d50629 100644
> > --- a/Documentation/devicetree/bindings/phy/phy-cadence-torrent.yaml
> > +++ b/Documentation/devicetree/bindings/phy/phy-cadence-torrent.yaml
> > @@ -34,7 +34,7 @@ properties:
> >   
> >     clocks:
> >       minItems: 1
> > -    maxItems: 2
> > +    maxItems: 3
> >       description:
> >         PHY input reference clocks - refclk (for PLL0) & pll1_refclk (for PLL1).
> >         pll1_refclk is optional and used for multi-protocol configurations requiring
> > @@ -45,9 +45,17 @@ properties:
> >   
> >     clock-names:
> >       minItems: 1
> > -    items:
> > -      - const: refclk
> > -      - enum: [ pll1_refclk, phy_en_refclk ]
> > +    maxItems: 3
> Drop
Sure, i will do that Krzysztof.
> > +    oneOf:
> > +      - items:
> > +          - const: refclk
> > +      - items:
> > +          - const: refclk
> > +          - enum: [ pll1_refclk, phy_en_refclk ]
> Drop these, pointless. You were supposed to grow existing syntax.
>
> > +      - items:
> > +          - const: refclk
> > +          - const: pll1_refclk
> So here is the enum.
>
> > +          - const: phy_en_refclk
> And this stays.
>
> You make changes which do not make the binding better and are not
> explained in commit msg. Focus on WHY you are doing things and also
> explain WHY you did such complicated syntax (if you insist on rewriting
> correct code into something odd we do not expect).

So, the reason I added the oneOf property is to support the following 
combinations because pll1_refclk and phy_en_refclk are optional clocks. 
With the earlier enum , only either of pll1_refclk or phy_en_refclk

can be used and both cannot be used at the same time.

Combination 1: refclk

Combination 2 : refclk, pll1_refclk

Combination 3: reclk, phy_en_refclk

Combination 4: refclk, pll1_refclk, phy_en_refclk


Please feel free to suggest any alternative solution to support these 
combinations .

> Best regards,
> Krzysztof