Re: [RFC PATCH v2 08/10] pps: generators: Add PPS Generator TIO Driver

Andy Shevchenko
2023-12-21T16:26:38Z

On Thu, Dec 21, 2023 at 03:02:52PM +0530, lakshmi.sowjanya.d@intel.com wrote:
> From: Lakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com>
>
> 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.

...

> +#include <linux/bits.h>
> +#include <linux/bitfield.h>
> +#include <linux/cleanup.h>

+ container_of.h

> +#include <linux/cpu.h>

+ device.h
+ err.h
+ hrtimer.h

> +#include <linux/io-64-nonatomic-hi-lo.h>

+ kstrtox.h

> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>

+ spinlock.h
+ sysfs.h

> +#include <linux/timekeeping.h>
> +#include <linux/types.h>

--
With Best Regards,
Andy Shevchenko