On 5/20/2020 8:56 AM, Dan Murphy wrote: > Andrew > > On 5/20/20 10:36 AM, Andrew Lunn wrote: >>>> Hi Dan >>>> >>>> Having it required with PHY_INTERFACE_MODE_RGMII_ID or >>>> PHY_INTERFACE_MODE_RGMII_RXID is pretty unusual. Normally these >>>> properties are used to fine tune the delay, if the default of 2ns does >>>> not work. >>> Also if the MAC phy-mode is configured with RGMII-ID and no internal >>> delay >>> values defined wouldn't that be counter intuitive? >> Most PHYs don't allow the delay to be fine tuned. You just pass for >> example PHY_INTERFACE_MODE_RGMII_ID to the PHY driver and it enables a >> 2ns delay. That is what people expect, and is documented. > >> Being able to tune the delay is an optional extra, which some PHYs >> support, but that is always above and beyond >> PHY_INTERFACE_MODE_RGMII_ID. > > I am interested in knowing where that is documented. I want to RTM I > grepped for a few different words but came up empty > > Since this is a tuneable phy we need to program the ID. 2ns is the > default value > > Maybe I can change it from Required to Configurable or Used. I do not think this is properly documented, it is an established practice, but it should be clearly documented somewhere, I do not know whether that belongs in the PHY Device Tree binding or if this belongs to the PHY documentation. -- Florian
