Re: [RFC PATCH v3 10/11] Documentation: driver-api: pps: Add Intel Timed I/O PPS generator
From: Randy Dunlap <hidden>
Date: 2024-01-03 22:13:23
Also in:
intel-wired-lan, linux-doc, linux-sound, lkml
On 1/3/24 03:56, lakshmi.sowjanya.d@intel.com wrote:
quoted hunk ↗ jump to hunk
From: Lakshmi Sowjanya D <redacted> Add Intel Timed I/O PPS usage instructions. Co-developed-by: Pandith N <redacted> Signed-off-by: Pandith N <redacted> Signed-off-by: Lakshmi Sowjanya D <redacted> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.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..cb1e4d814d37 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 signal.
can generate a PPS signal.
or
can generate PPS signals.
+ +Timed I/O and system time are both driven by same hardware clock, The signal
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
share
+Timed I/O device. There are dedicated Timed I/O pins to deliver PPS signal
maybe: 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
-- #Randy