Messages in this thread | | | Date | Wed, 20 Mar 2024 17:18:18 +0100 | Subject | Re: [PATCH v5 10/11] Documentation: driver-api: pps: Add Intel Timed I/O PPS generator | From | Rodolfo Giometti <> |
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On 19/03/24 14:05, lakshmi.sowjanya.d@intel.com wrote: > From: Lakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com> > > Add Intel Timed I/O PPS usage instructions. > > Co-developed-by: Pandith N <pandith.n@intel.com> > Signed-off-by: Pandith N <pandith.n@intel.com> > Signed-off-by: Lakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
> --- > Documentation/driver-api/pps.rst | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/Documentation/driver-api/pps.rst b/Documentation/driver-api/pps.rst > index 78dded03e5d8..52a6d5faf885 100644 > --- a/Documentation/driver-api/pps.rst > +++ b/Documentation/driver-api/pps.rst > @@ -246,3 +246,25 @@ 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, > +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
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