109 lines
3.0 KiB
Groff
109 lines
3.0 KiB
Groff
.TH PHC_CTL 8 "June 2014" "linuxptp"
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.SH NAME
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phc_ctl \- directly control PHC device clock
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.SH SYNOPSIS
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.B phc_ctl
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[ options ] <device> [ commands ]
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.SH DESCRIPTION
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.B phc_ctl
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is a program which can be used to directly control a PHC clock device.
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Typically, it is used for debugging purposes, and has little use for general
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control of the device. For general control of PHC clock devices,
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.B phc2sys (8)
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should be preferred.
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<device> may be either CLOCK_REALTIME, any /dev/ptpX device, or any ethernet
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device which supports ethtool's get_ts_info ioctl.
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.SH OPTIONS
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.TP
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.BI \-l " print-level"
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Set the maximum syslog level of messages which should be printed or sent to the
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system logger. The default is 6 (LOG_INFO).
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.TP
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.BI \-q
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Do not send messages to syslog. By default messages will be sent.
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.TP
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.BI \-Q
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Do not print messages to standard output. By default messages will be printed.
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.TP
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.BI \-h
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Display a help message.
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.TP
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.B \-v
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Prints the software version and exits.
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.SH COMMANDS
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.B phc_ctl
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is controlled by passing commands which take either an optional or required
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parameter. The commands (outlined below) will control aspects of the PHC clock
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device. These commands may be useful for inspecting or debugging the PHC
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driver, but may have adverse side effects on running instances of
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.B ptp4l (8)
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or
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.B phc2sys (8)
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.TP
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.BI set " seconds"
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Set the PHC clock time to the value specified in seconds. Defaults to reading
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CLOCK_REALTIME if no value is provided.
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.TP
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.BI get
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Get the current time of the PHC clock device.
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.TP
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.BI adj " seconds"
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Adjust the PHC clock by an amount of seconds provided. This argument is required.
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.TP
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.BI freq " ppb"
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Adjust the frequency of the PHC clock by the specified parts per billion. If no
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argument is provided, it will attempt to read the current frequency and report
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it.
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.TP
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.BI cmp
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Compare the PHC clock device to CLOCK_REALTIME, using the best method available.
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.TP
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.BI caps
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Display the device capabilities. This is the default command if no commands are
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provided.
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.TP
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.BI wait " seconds"
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Sleep the process for the specified period of time, waking up and resuming
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afterwards. This command may be useful for sanity checking whether the PHC
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clock is running as expected.
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The arguments specified in seconds are read as double precision floating point
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values, and will scale to nanoseconds. This means providing a value of 5.5
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means 5 and one half seconds. This allows specifying fairly precise values for time.
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.SH EXAMPLES
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Read the current clock time from the device
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.RS
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\f(CWphc_ctl /dev/ptp0 get\fP
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.RE
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Set the PHC clock time to CLOCK_REALTIME
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.RS
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\f(CWphc_ctl /dev/ptp0 set\fP
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.RE
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Set PHC clock time to 0 (seconds since Epoch)
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.RS
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\f(CWphc_ctl /dev/ptp0 set 0.0\fP
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.RE
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Quickly sanity check frequency slewing by setting slewing frequency by positive
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10%, resetting clock to 0.0 time, waiting for 10 seconds, and then reading
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time. The time read back should be (roughly) 11 seconds, since the clock was
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slewed 10% faster.
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.RS
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\f(CWphc_ctl /dev/ptp0 freq 100000000 set 0.0 wait 10.0 get
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.RE
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.SH SEE ALSO
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.BR ptp4l (8)
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.BR phc2sys (8)
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