On 28/11/2016 18:43, Florian Fainelli wrote: > On 11/28/2016 02:34 AM, Sebastian Frias wrote: > >> For what is worth, the Atheros at803x driver comes with RX delay enabled >> as per HW reset. > > Always, or is this a behavior possibly defined via a stra-pin that can > be changed?
Here's the data sheet: http://www.redeszone.net/app/uploads/2014/04/AR8035.pdf 4.2.25 rgmii rx clock delay control Offset: 0x00 bit 15: Control bit for rgmii interface rx clock delay: 1 = rgmii rx clock delay enable 0 = rgmii rx clock delay disable HW Rst. 1 SW Rst. 1 As far as I can tell, rx delay is enabled by default, always. The "Features" list mentions "RGMII timing modes support internal delay and external delay on Rx path" (Not sure about the internal vs external distinction.) Table 3-6. RGMII AC Characteristics — no Internal Delay Table 3-7. RGMII AC Characteristics — with internal delay added (Default) Delay is 2 ns apparently. There's also 4.2.27 Hib ctrl and rgmii gtx clock delay register Offset: 0x0B bits 6:5 Gtx_dly_val Select the delay of gtx_clk. 00:0.25ns 01:1.3ns 10:2.4ns 11:3.4ns I don't know what that is used for. Maybe this is the external vs internal delay? Regards.
