1PHC_CTL(8)                  System Manager's Manual                 PHC_CTL(8)
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NAME

6       phc_ctl - directly control PHC device clock
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SYNOPSIS

10       phc_ctl [ options ] <device> [ commands ]
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DESCRIPTION

14       phc_ctl  is a program which can be used to directly control a PHC clock
15       device.  Typically, it is used for debugging purposes, and  has  little
16       use for general control of the device. For general control of PHC clock
17       devices, phc2sys (8) should be preferred.
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19       <device> may be either CLOCK_REALTIME, any  /dev/ptpX  device,  or  any
20       ethernet device which supports ethtool's get_ts_info ioctl.
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OPTIONS

24       -l print-level
25              Set the maximum syslog level of messages which should be printed
26              or sent to the system logger. The default is 6 (LOG_INFO).
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28       -q     Do not send messages to syslog.  By  default  messages  will  be
29              sent.
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31       -Q     Do  not  print  messages to standard output. By default messages
32              will be printed.
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34       -h     Display a help message.
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36       -v     Prints the software version and exits.
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COMMANDS

40       phc_ctl is controlled by passing commands which take either an optional
41       or  required  parameter.  The  commands  (outlined  below) will control
42       aspects of the PHC clock device.  These  commands  may  be  useful  for
43       inspecting  or  debugging  the  PHC  driver,  but may have adverse side
44       effects on running instances of ptp4l (8) or phc2sys (8)
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47       set seconds
48              Set the PHC clock  time  to  the  value  specified  in  seconds.
49              Defaults to reading CLOCK_REALTIME if no value is provided.
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51       get    Get the current time of the PHC clock device.
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53       adj seconds
54              Adjust  the  PHC  clock  by  an amount of seconds provided. This
55              argument is required.
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57       freq ppb
58              Adjust the frequency of the PHC clock by the specified parts per
59              billion. If no argument is provided, it will attempt to read the
60              current frequency and report it.
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62       cmp    Compare the PHC clock device to CLOCK_REALTIME, using  the  best
63              method available.
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65       caps   Display  the device capabilities. This is the default command if
66              no commands are provided.
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68       wait seconds
69              Sleep the process for the specified period of  time,  waking  up
70              and  resuming  afterwards. This command may be useful for sanity
71              checking whether the PHC clock is running as expected.
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73              The arguments specified in seconds are read as double  precision
74              floating point values, and will scale to nanoseconds. This means
75              providing a value of 5.5 means 5  and  one  half  seconds.  This
76              allows specifying fairly precise values for time.
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EXAMPLES

80       Read the current clock time from the device
81              phc_ctl /dev/ptp0 get
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83       Set the PHC clock time to CLOCK_REALTIME
84              phc_ctl /dev/ptp0 set
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86       Set PHC clock time to 0 (seconds since Epoch)
87              phc_ctl /dev/ptp0 set 0.0
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89       Quickly  sanity check frequency slewing by setting slewing frequency by
90       positive 10%, resetting clock to 0.0 time, waiting for 10 seconds,  and
91       then  reading  time. The time read back should be (roughly) 11 seconds,
92       since the clock was slewed 10% faster.
93              phc_ctl /dev/ptp0 freq 100000000 set 0.0 wait 10.0 get
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SEE ALSO

97       ptp4l(8) phc2sys(8)
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101linuxptp                           June 2014                        PHC_CTL(8)
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