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/ptp<N>/
  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/ptp<N>/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/ptp<N>/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/ptp<N>/max_vclocks
  37 Date:           May 2021
  38 Contact:        Yangbo Lu <yangbo.lu@nxp.com>
  39 Description:
  40                 This file contains the maximum number of ptp vclocks.
  41                 Write integer to re-configure it.
  42
  43 What:           /sys/class/ptp/ptp<N>/n_alarms
  44 Date:           September 2010
  45 Contact:        Richard Cochran <richardcochran@gmail.com>
  46 Description:
  47                 This file contains the number of periodic or one shot
  48                 alarms offer by the PTP hardware clock.
  49
  50 What:           /sys/class/ptp/ptp<N>/n_external_timestamps
  51 Date:           September 2010
  52 Contact:        Richard Cochran <richardcochran@gmail.com>
  53 Description:
  54                 This file contains the number of external timestamp
  55                 channels offered by the PTP hardware clock.
  56
  57 What:           /sys/class/ptp/ptp<N>/n_periodic_outputs
  58 Date:           September 2010
  59 Contact:        Richard Cochran <richardcochran@gmail.com>
  60 Description:
  61                 This file contains the number of programmable periodic
  62                 output channels offered by the PTP hardware clock.
  63
  64 What:           /sys/class/ptp/ptp<N>/n_pins
  65 Date:           March 2014
  66 Contact:        Richard Cochran <richardcochran@gmail.com>
  67 Description:
  68                 This file contains the number of programmable pins
  69                 offered by the PTP hardware clock.
  70
  71 What:           /sys/class/ptp/ptp<N>/n_vclocks
  72 Date:           May 2021
  73 Contact:        Yangbo Lu <yangbo.lu@nxp.com>
  74 Description:
  75                 This file contains the number of virtual PTP clocks in
  76                 use.  By default, the value is 0 meaning that only the
  77                 physical clock is in use.  Setting the value creates
  78                 the corresponding number of virtual clocks and causes
  79                 the physical clock to become free running.  Setting the
  80                 value back to 0 deletes the virtual clocks and
  81                 switches the physical clock back to normal, adjustable
  82                 operation.
  83
  84 What:           /sys/class/ptp/ptp<N>/pins
  85 Date:           March 2014
  86 Contact:        Richard Cochran <richardcochran@gmail.com>
  87 Description:
  88                 This directory contains one file for each programmable
  89                 pin offered by the PTP hardware clock. The file name
  90                 is the hardware dependent pin name. Reading from this
  91                 file produces two numbers, the assigned function (see
  92                 the `PTP_PF_` enumeration values in linux/ptp_clock.h)
  93                 and the channel number. The function and channel
  94                 assignment may be changed by two writing numbers into
  95                 the file.
  96
  97 What:           /sys/class/ptp/ptp<N>/pps_available
  98 Date:           September 2010
  99 Contact:        Richard Cochran <richardcochran@gmail.com>
 100 Description:
 101                 This file indicates whether the PTP hardware clock
 102                 supports a Pulse Per Second to the host CPU. Reading
 103                 "1" means that the PPS is supported, while "0" means
 104                 not supported.
 105
 106 What:           /sys/class/ptp/ptp<N>/extts_enable
 107 Date:           September 2010
 108 Contact:        Richard Cochran <richardcochran@gmail.com>
 109 Description:
 110                 This write-only file enables or disables external
 111                 timestamps. To enable external timestamps, write the
 112                 channel index followed by a "1" into the file.
 113                 To disable external timestamps, write the channel
 114                 index followed by a "0" into the file.
 115
 116 What:           /sys/class/ptp/ptp<N>/fifo
 117 Date:           September 2010
 118 Contact:        Richard Cochran <richardcochran@gmail.com>
 119 Description:
 120                 This file provides timestamps on external events, in
 121                 the form of three integers: channel index, seconds,
 122                 and nanoseconds.
 123
 124 What:           /sys/class/ptp/ptp<N>/period
 125 Date:           September 2010
 126 Contact:        Richard Cochran <richardcochran@gmail.com>
 127 Description:
 128                 This write-only file enables or disables periodic
 129                 outputs. To enable a periodic output, write five
 130                 integers into the file: channel index, start time
 131                 seconds, start time nanoseconds, period seconds, and
 132                 period nanoseconds. To disable a periodic output, set
 133                 all the seconds and nanoseconds values to zero.
 134
 135 What:           /sys/class/ptp/ptp<N>/pps_enable
 136 Date:           September 2010
 137 Contact:        Richard Cochran <richardcochran@gmail.com>
 138 Description:
 139                 This write-only file enables or disables delivery of
 140                 PPS events to the Linux PPS subsystem. To enable PPS
 141                 events, write a "1" into the file. To disable events,
 142                 write a "0" into the file.