>From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of >Jakub Kicinski >Sent: Friday, May 30, 2025 2:49 AM > >On Fri, 23 May 2025 19:26:48 +0200 Arkadiusz Kubalewski wrote: >> +The device may support the Reference SYNC feature, which allows the >>combination >> +of two inputs into a Reference SYNC pair. In this configuration, clock >>signals >> +from both inputs are used to synchronize the dpll device. The higher >>frequency >> +signal is utilized for the loop bandwidth of the DPLL, while the lower >>frequency >> +signal is used to syntonize the output signal of the DPLL device. This >>feature >> +enables the provision of a high-quality loop bandwidth signal from an >>external >> +source. > >I'm uninitiated into the deeper arts of time sync, but to me this >sounds like a reference clock. Are you trying not to call it clock >because in time clock means a ticker, and this is an oscillator? > We shall refer to a reference clock for each input pin, right? TBH, I have reused the name from dpll chip docs, I believe they have tried to make similar features and naming convention for both: Embedded SYNC/Reference SYNC, and that makes some sense. >> +A capable input provides a list of inputs that can be paired to create a >> +Reference SYNC pair. To control this feature, the user must request a >>desired >> +state for a target pin: use ``DPLL_PIN_STATE_CONNECTED`` to enable or >> +``DPLL_PIN_STATE_DISCONNECTED`` to disable the feature. Only two pins >>can be >> +bound to form a Reference SYNC pair at any given time. > >Mostly I got confused by the doc saying "Reference SYNC pair". >I was expecting that you'll have to provide 2 ref sync signals. >But IIUC the first signal is still the existing signal we lock >into, so the pair is of a reference sync + an input pin? >Not a pair of two reference syncs. > >IOW my reading of the doc made me expect 2 pins to always be passed in >as ref sync, but the example from the cover letter shows only adding >one. Yes, exactly, will try to improve this in next version. Thank you! Arkadiusz
