d94ba80ebb
This patch adds an infrastructure for hardware clocks that implement IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a registration method to particular hardware clock drivers. Each clock is presented as a standard POSIX clock. The ancillary clock features are exposed in two different ways, via the sysfs and by a character device. Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: John Stultz <john.stultz@linaro.org>
99 lines
3.3 KiB
Plaintext
99 lines
3.3 KiB
Plaintext
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/ptpN/
|
|
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/ptpN/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.
|
|
|
|
What: /sys/class/ptp/ptpN/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/ptpN/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/ptpN/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/ptpN/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/ptpN/pps_avaiable
|
|
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/ptpN/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/ptpN/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/ptpN/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/ptpN/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.
|