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author | Richard Cochran <richardcochran@gmail.com> | 2011-04-22 12:03:08 +0200 |
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committer | John Stultz <john.stultz@linaro.org> | 2011-05-23 22:01:00 +0200 |
commit | d94ba80ebbea17f036cecb104398fbcd788aa742 (patch) | |
tree | 7fe40228c5ea2bb77f2892b722d27155df8c1157 /Documentation/ABI | |
parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryu... (diff) | |
download | linux-d94ba80ebbea17f036cecb104398fbcd788aa742.tar.xz linux-d94ba80ebbea17f036cecb104398fbcd788aa742.zip |
ptp: Added a brand new class driver for ptp clocks.
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>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r-- | Documentation/ABI/testing/sysfs-ptp | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-ptp b/Documentation/ABI/testing/sysfs-ptp new file mode 100644 index 000000000000..d40d2b550502 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-ptp @@ -0,0 +1,98 @@ +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. |