Re: [PATCH 2/3] dt-bindings: mscc: Add RGMII RX and TX delay tuning

[Harini Katakam]

Hi Andrew,

On Tue, Jun 29, 2021 at 7:37 PM Andrew Lunn <andrew@xxxxxxx> wrote:
>
> On Tue, Jun 29, 2021 at 03:10:37PM +0530, Harini Katakam wrote:
> > Add optional properties to tune RGMII RX and TX delay.
> >
> > Signed-off-by: Harini Katakam <harini.katakam@xxxxxxxxxx>
> > Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxxxxx>
> > Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
> > ---
> >  .../devicetree/bindings/net/mscc-phy-vsc8531.txt         | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt b/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt
> > index 87a27d775d48..e201d24d8e27 100644
> > --- a/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt
> > +++ b/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt
> > @@ -33,7 +33,14 @@ Optional properties:
> >                         VSC8531_DUPLEX_COLLISION (8).
> >  - load-save-gpios    : GPIO used for the load/save operation of the PTP
> >                         hardware clock (PHC).
> > -
> > +- vsc8531,rx-delay   : RGMII RX delay. Allowed values are defined in
> > +                       "include/dt-bindings/net/mscc-phy-vsc8531.h".
> > +                       Default value, set by the driver is
> > +                       VSC8531_RGMII_CLK_DELAY_2_0_NS.
> > +- vsc8531,tx-delay   : RGMII TX delay. Allowed values are defined in
> > +                       "include/dt-bindings/net/mscc-phy-vsc8531.h".
> > +                       Default value, set by the driver is
> > +                       VSC8531_RGMII_CLK_DELAY_2_0_NS.
>
> The default values need better explanation. So you are saying they are
> only used when 'rgmii' is not used. And they replace the default 2ns
> delay, they don't add to the default 2ns delay.

Thanks for the review. Yes, I'm saying that they replace the default 2ns delay.
But they only come in when rgmii or rgmii-id is used. When that's not used,
the default 0.2ns in the driver is retained. I'll update the DT description here
to be clear.

Regards,
Harini