Am Fri, Mar 07, 2025 at 02:39:32PM +0100 schrieb Andrew Lunn: > On Fri, Mar 07, 2025 at 11:30:00AM +0100, Dimitri Fedrau via B4 Relay wrote: > > The dp83822 provides the possibility to set the resistance value of the > > the MAC series termination. Modifying the resistance to an appropriate > > value can reduce signal reflections and therefore improve signal quality. > > I have some dumb questions.... > > By referring to MAC from the perspective of the PHY, do you mean the > termination of the bus between the MAC and the PHY? The SGMII SERDES, > or RGMII? > - Yes, the perspective is from the PHY. - Yes, but only the outputs towards the MAC. Resistors can be saved on the PCB when they are integrated into the PHY. - The PHY is able to operate with RGMII, RMII and MII. Should I rename then "mac-series-termination-ohms" to "output-mac-series-termination-ohms" or similar ? > I'm assuming the terminology is direct from the datasheet of the PHY? > But since this is a bit of a niche area, no other PHY driver currently > supports anythings like this, the terminology is not well known. So it > would be good to expand the description, to make it really clear what > you are talking about, so if anybody else wants to add the same > feature, they make use of the property, not add a new property. The datasheet calls it MAC impedance control, that is what someone might want to achieve when selecting the proper resistance value. I named it "mac-series-termination-ohms" instead to make sure what is done to achieve impedance matching. Should I add the proper description in the bindings ? Description of the properties are somehow short. However will expand the description. Best regards, Dimitri Fedrau
