Documentation/ABI/testing/sysfs-ptp

   1 What:           /sys/class/ptp/
   2 Date:           September 2010
   3 Contact:        Richard Cochran <richardcochran@gmail.com>
   4 Description:
   5                 This directory contains files and directories
   6                 providing a standardized interface to the ancillary
   7                 features of PTP hardware clocks.
   8
   9 What:           /sys/class/ptp/ptpN/
  10 Date:           September 2010
  11 Contact:        Richard Cochran <richardcochran@gmail.com>
  12 Description:
  13                 This directory contains the attributes of the Nth PTP
  14                 hardware clock registered into the PTP class driver
  15                 subsystem.
  16
  17 What:           /sys/class/ptp/ptpN/clock_name
  18 Date:           September 2010
  19 Contact:        Richard Cochran <richardcochran@gmail.com>
  20 Description:
  21                 This file contains the name of the PTP hardware clock
  22                 as a human readable string. The purpose of this
  23                 attribute is to provide the user with a "friendly
  24                 name" and to help distinguish PHY based devices from
  25                 MAC based ones. The string does not necessarily have
  26                 to be any kind of unique id.
  27
  28 What:           /sys/class/ptp/ptpN/max_adjustment
  29 Date:           September 2010
  30 Contact:        Richard Cochran <richardcochran@gmail.com>
  31 Description:
  32                 This file contains the PTP hardware clock's maximum
  33                 frequency adjustment value (a positive integer) in
  34                 parts per billion.
  35
  36 What:           /sys/class/ptp/ptpN/n_alarms
  37 Date:           September 2010
  38 Contact:        Richard Cochran <richardcochran@gmail.com>
  39 Description:
  40                 This file contains the number of periodic or one shot
  41                 alarms offer by the PTP hardware clock.
  42
  43 What:           /sys/class/ptp/ptpN/n_external_timestamps
  44 Date:           September 2010
  45 Contact:        Richard Cochran <richardcochran@gmail.com>
  46 Description:
  47                 This file contains the number of external timestamp
  48                 channels offered by the PTP hardware clock.
  49
  50 What:           /sys/class/ptp/ptpN/n_periodic_outputs
  51 Date:           September 2010
  52 Contact:        Richard Cochran <richardcochran@gmail.com>
  53 Description:
  54                 This file contains the number of programmable periodic
  55                 output channels offered by the PTP hardware clock.
  56
  57 What:           /sys/class/ptp/ptpN/n_pins
  58 Date:           March 2014
  59 Contact:        Richard Cochran <richardcochran@gmail.com>
  60 Description:
  61                 This file contains the number of programmable pins
  62                 offered by the PTP hardware clock.
  63
  64 What:           /sys/class/ptp/ptpN/pins
  65 Date:           March 2014
  66 Contact:        Richard Cochran <richardcochran@gmail.com>
  67 Description:
  68                 This directory contains one file for each programmable
  69                 pin offered by the PTP hardware clock. The file name
  70                 is the hardware dependent pin name. Reading from this
  71                 file produces two numbers, the assigned function (see
  72                 the `PTP_PF_` enumeration values in linux/ptp_clock.h)
  73                 and the channel number. The function and channel
  74                 assignment may be changed by two writing numbers into
  75                 the file.
  76
  77 What:           /sys/class/ptp/ptpN/pps_available
  78 Date:           September 2010
  79 Contact:        Richard Cochran <richardcochran@gmail.com>
  80 Description:
  81                 This file indicates whether the PTP hardware clock
  82                 supports a Pulse Per Second to the host CPU. Reading
  83                 "1" means that the PPS is supported, while "0" means
  84                 not supported.
  85
  86 What:           /sys/class/ptp/ptpN/extts_enable
  87 Date:           September 2010
  88 Contact:        Richard Cochran <richardcochran@gmail.com>
  89 Description:
  90                 This write-only file enables or disables external
  91                 timestamps. To enable external timestamps, write the
  92                 channel index followed by a "1" into the file.
  93                 To disable external timestamps, write the channel
  94                 index followed by a "0" into the file.
  95
  96 What:           /sys/class/ptp/ptpN/fifo
  97 Date:           September 2010
  98 Contact:        Richard Cochran <richardcochran@gmail.com>
  99 Description:
 100                 This file provides timestamps on external events, in
 101                 the form of three integers: channel index, seconds,
 102                 and nanoseconds.
 103
 104 What:           /sys/class/ptp/ptpN/period
 105 Date:           September 2010
 106 Contact:        Richard Cochran <richardcochran@gmail.com>
 107 Description:
 108                 This write-only file enables or disables periodic
 109                 outputs. To enable a periodic output, write five
 110                 integers into the file: channel index, start time
 111                 seconds, start time nanoseconds, period seconds, and
 112                 period nanoseconds. To disable a periodic output, set
 113                 all the seconds and nanoseconds values to zero.
 114
 115 What:           /sys/class/ptp/ptpN/pps_enable
 116 Date:           September 2010
 117 Contact:        Richard Cochran <richardcochran@gmail.com>
 118 Description:
 119                 This write-only file enables or disables delivery of
 120                 PPS events to the Linux PPS subsystem. To enable PPS
 121                 events, write a "1" into the file. To disable events,
 122                 write a "0" into the file.