diff mbox series

[RFC,v3,10/11] Documentation: driver-api: pps: Add Intel Timed I/O PPS generator

Message ID 20240103115602.19044-11-lakshmi.sowjanya.d@intel.com
State New
Headers
Series Add support for Intel PPS Generator |

Commit Message

D, Lakshmi Sowjanya Jan. 3, 2024, 11:56 a.m. UTC 
  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>
---
 Documentation/driver-api/pps.rst | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Comments

Randy Dunlap Jan. 3, 2024, 10:13 p.m. UTC | #1 
On 1/3/24 03:56, 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>
> ---
>  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
diff mbox series

Patch

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.
+
+Timed I/O and system time are both driven by same hardware clock, The signal
+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 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