[PATCH net-next v2 2/3] net: ethernet: ti: am65-cpsw: fixup PHY mode for fixed RGMII TX delay

[Andrew Lunn]

On Mon, Jul 14, 2025 at 12:01:22PM +0200, Michael Walle wrote:
> Hi,
> 
> On Tue Jun 24, 2025 at 12:53 PM CEST, Matthias Schiffer wrote:
> > All am65-cpsw controllers have a fixed TX delay, so the PHY interface
> > mode must be fixed up to account for this.
> >
> > Modes that claim to a delay on the PCB can't actually work. Warn people
> > to update their Device Trees if one of the unsupported modes is specified.
> >
> > Signed-off-by: Matthias Schiffer <matthias.schiffer at ew.tq-group.com>
> > Reviewed-by: Maxime Chevallier <maxime.chevallier at bootlin.com>
> > Reviewed-by: Andrew Lunn <andrew at lunn.ch>
> 
> For whatever reason, this patch is breaking network on our board
> (just transmission). We have rgmii-id in our devicetree which is now
> modified to be just rgmii-rxid. The board has a TI AM67A (J722S) with a
> Broadcom BCM54210E PHY. I'm not sure, if AM67A MAC doesn't add any
> delay or if it's too small. I'll need to ask around if there are any
> measurements but my colleague doing the measurements is on holiday
> at the moment.

I agree, we need to see if this is a AM65 vs AM67 issue. rgmii-id
would be correct if the MAC is not adding delays.

Do you have access to the datasheets for both? Can you do a side by
side comparison for the section which describes the fixed TX delay?

	Andrew