pps: generators: Add PPS Generator TIO Driver

pps: generators: Add PPS Generator TIO Driver

The Intel Timed IO PPS generator driver outputs a PPS signal using
dedicated hardware that is more accurate than software actuated PPS.
The Timed IO hardware generates output events using the ART timer.
The ART timer period varies based on platform type, but is less than 100
nanoseconds for all current platforms. Timed IO output accuracy is
within 1 ART period.

PPS output is enabled by writing '1' the 'enable' sysfs attribute. The
driver uses hrtimers to schedule a wake-up 10 ms before each event
(edge) target time. At wakeup, the driver converts the target time in
terms of CLOCK_REALTIME to ART trigger time and writes this to the Timed
IO hardware. The Timed IO hardware generates an event precisely at the
requested system time without software involvement.

Co-developed-by: Christopher Hall <christopher.s.hall@intel.com>
Signed-off-by: Christopher Hall <christopher.s.hall@intel.com>
Co-developed-by: Pandith N <pandith.n@intel.com>
Signed-off-by: Pandith N <pandith.n@intel.com>
Co-developed-by: Thejesh Reddy T R <thejesh.reddy.t.r@intel.com>
Signed-off-by: Thejesh Reddy T R <thejesh.reddy.t.r@intel.com>
Signed-off-by: Lakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Subramanian Mohan <subramanian.mohan@intel.com>
Link: https://lore.kernel.org/r/20250219040618.70962-3-subramanian.mohan@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>