On Wed, Jun 12, 2024 at 10:02:46AM +0200, Greg KH wrote: > On Wed, Jun 12, 2024 at 09:23:58AM +0530, lakshmi.sowjanya.d@xxxxxxxxx wrote: > > From: Lakshmi Sowjanya D <lakshmi.sowjanya.d@xxxxxxxxx> > > > > Add Intel Timed I/O PPS usage instructions. > > > > Co-developed-by: Pandith N <pandith.n@xxxxxxxxx> > > Signed-off-by: Pandith N <pandith.n@xxxxxxxxx> > > Signed-off-by: Lakshmi Sowjanya D <lakshmi.sowjanya.d@xxxxxxxxx> > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > > Acked-by: Rodolfo Giometti <giometti@xxxxxxxxxxxx> > > --- > > Documentation/driver-api/pps.rst | 24 ++++++++++++++++++++++++ > > 1 file changed, 24 insertions(+) > > > > diff --git a/Documentation/driver-api/pps.rst b/Documentation/driver-api/pps.rst > > index 78dded03e5d8..75f7b094f963 100644 > > --- a/Documentation/driver-api/pps.rst > > +++ b/Documentation/driver-api/pps.rst > > @@ -246,3 +246,27 @@ 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/devices/platform/INTCxxxx\:00/enable > > + > > +Stop generating PPS signal:: > > + > > + $echo 0 > /sys/devices/platform/INTCxxxx\:00/enable > > Why is this not described in Documenation/ABI/ ? Oops, that was patch 3/3, sorry.
