On Wed, Sep 03, 2025 at 04:37:48PM +0800, Wei Fang wrote: > The NETC Timer supports looping back the output pulse signal of Fiper-n > into Trigger-n input, so that users can leverage this feature to validate > some other features without external hardware support. For example, users > can use it to test external trigger stamp (EXTTS). And users can combine > EXTTS with loopback mode to check whether the generation time of PPS is > aligned with an integral second of PHC, or the periodic output signal > (PTP_CLK_REQ_PEROUT) whether is generated at the specified time. > > Since ptp_clock_info::perout_loopback() has been added to the ptp_clock > driver as a generic interface to enable or disable the periodic output > signal loopback, therefore, netc_timer_perout_loopback() is added as a > callback of ptp_clock_info::perout_loopback(). > > Test the generation time of PPS event: > > $ echo 0 1 > /sys/kernel/debug/ptp0/perout_loopback > $ echo 1 > /sys/class/ptp/ptp0/pps_enable > $ testptp -d /dev/ptp0 -e 3 > external time stamp request okay > event index 0 at 63.000000017 > event index 0 at 64.000000017 > event index 0 at 65.000000017 > > Test the generation time of the periodic output signal: > > $ echo 0 1 > /sys/kernel/debug/ptp0/perout_loopback > $ echo 0 150 0 1 500000000 > /sys/class/ptp/ptp0/period > $ testptp -d /dev/ptp0 -e 3 > external time stamp request okay > event index 0 at 150.000000014 > event index 0 at 151.500000015 > event index 0 at 153.000000014 > > Signed-off-by: Wei Fang <[email protected]> > ---
Reviewed-by: Vladimir Oltean <[email protected]>
