Commit 6b22c3de authored by Subramanian Mohan's avatar Subramanian Mohan Committed by Greg Kroah-Hartman
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Documentation: driver-api: pps: Add Intel Timed I/O PPS generator 



Add Intel Timed I/O PPS usage instructions.

Co-developed-by: default avatarPandith N <pandith.n@intel.com>
Signed-off-by: default avatarPandith N <pandith.n@intel.com>
Signed-off-by: default avatarLakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarRodolfo Giometti <giometti@enneenne.com>
Signed-off-by: default avatarSubramanian Mohan <subramanian.mohan@intel.com>
Link: https://lore.kernel.org/r/20250219040618.70962-4-subramanian.mohan@intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c89755d1

Documentation/driver-api/pps.rst

+24 −0
Original line number Diff line number Diff line
@@ -285,3 +285,27 @@ delay between assert and clear edge as small as possible to reduce system 
latencies. But if it is too small slave won't be able to capture clear edge

transition. The default of 30us should be good enough in most situations.

The delay can be selected using 'delay' pps_gen_parport module parameter.





Intel Timed I/O PPS signal generator

------------------------------------



Intel Timed I/O is a high precision device, present on 2019 and newer Intel

CPUs, that can generate PPS signals.



Timed I/O and system time are both driven by same hardware clock. The signal

is generated with a precision of ~20 nanoseconds. The generated PPS signal

is used to synchronize an external device with system clock. For example,

it can be used to share your clock with a device that receives PPS signal,

generated by Timed I/O device. There are dedicated Timed I/O pins to deliver

the PPS signal to an external device.



Usage of Intel Timed I/O as PPS generator:



Start generating PPS signal::



        $echo 1 > /sys/class/pps-gen/pps-genx/enable



Stop generating PPS signal::



        $echo 0 > /sys/class/pps-gen/pps-genx/enable