original_kernel/Documentation/ABI/testing/sysfs-ptp

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What: /sys/class/ptp/
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This directory contains files and directories
providing a standardized interface to the ancillary
features of PTP hardware clocks.
What: /sys/class/ptp/ptp<N>/
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This directory contains the attributes of the Nth PTP
hardware clock registered into the PTP class driver
subsystem.
What: /sys/class/ptp/ptp<N>/clock_name
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file contains the name of the PTP hardware clock
as a human readable string. The purpose of this
attribute is to provide the user with a "friendly
name" and to help distinguish PHY based devices from
MAC based ones. The string does not necessarily have
to be any kind of unique id.
What: /sys/class/ptp/ptp<N>/max_adjustment
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file contains the PTP hardware clock's maximum
frequency adjustment value (a positive integer) in
parts per billion.
What: /sys/class/ptp/ptp<N>/max_vclocks
Date: May 2021
Contact: Yangbo Lu <yangbo.lu@nxp.com>
Description:
This file contains the maximum number of ptp vclocks.
Write integer to re-configure it.
What: /sys/class/ptp/ptp<N>/n_alarms
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file contains the number of periodic or one shot
alarms offer by the PTP hardware clock.
What: /sys/class/ptp/ptp<N>/n_external_timestamps
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file contains the number of external timestamp
channels offered by the PTP hardware clock.
What: /sys/class/ptp/ptp<N>/n_periodic_outputs
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file contains the number of programmable periodic
output channels offered by the PTP hardware clock.
What: /sys/class/ptp/ptp<N>/n_pins
Date: March 2014
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file contains the number of programmable pins
offered by the PTP hardware clock.
What: /sys/class/ptp/ptp<N>/n_vclocks
Date: May 2021
Contact: Yangbo Lu <yangbo.lu@nxp.com>
Description:
This file contains the number of virtual PTP clocks in
use. By default, the value is 0 meaning that only the
physical clock is in use. Setting the value creates
the corresponding number of virtual clocks and causes
the physical clock to become free running. Setting the
value back to 0 deletes the virtual clocks and
switches the physical clock back to normal, adjustable
operation.
What: /sys/class/ptp/ptp<N>/pins
Date: March 2014
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This directory contains one file for each programmable
pin offered by the PTP hardware clock. The file name
is the hardware dependent pin name. Reading from this
file produces two numbers, the assigned function (see
the `PTP_PF_` enumeration values in linux/ptp_clock.h)
and the channel number. The function and channel
assignment may be changed by two writing numbers into
the file.
What: /sys/class/ptp/ptp<N>/pps_available
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file indicates whether the PTP hardware clock
supports a Pulse Per Second to the host CPU. Reading
"1" means that the PPS is supported, while "0" means
not supported.
What: /sys/class/ptp/ptp<N>/extts_enable
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This write-only file enables or disables external
timestamps. To enable external timestamps, write the
channel index followed by a "1" into the file.
To disable external timestamps, write the channel
index followed by a "0" into the file.
What: /sys/class/ptp/ptp<N>/fifo
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This file provides timestamps on external events, in
the form of three integers: channel index, seconds,
and nanoseconds.
What: /sys/class/ptp/ptp<N>/period
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This write-only file enables or disables periodic
outputs. To enable a periodic output, write five
integers into the file: channel index, start time
seconds, start time nanoseconds, period seconds, and
period nanoseconds. To disable a periodic output, set
all the seconds and nanoseconds values to zero.
What: /sys/class/ptp/ptp<N>/pps_enable
Date: September 2010
Contact: Richard Cochran <richardcochran@gmail.com>
Description:
This write-only file enables or disables delivery of
PPS events to the Linux PPS subsystem. To enable PPS
events, write a "1" into the file. To disable events,
write a "0" into the file.