linux-imx/Documentation/ABI/testing/sysfs-timecard

What: /sys/class/timecard/ Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: This directory contains files and directories providing a standardized interface to the ancillary features of the OpenCompute timecard.

What: /sys/class/timecard/ocpN/ Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: This directory contains the attributes of the Nth timecard registered.

What: /sys/class/timecard/ocpN/available_clock_sources Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) The list of available time sources that the PHC uses for clock adjustments.

	====  =================================================
            NONE  no adjustments
            PPS   adjustments come from the PPS1 selector (default)
            TOD   adjustments from the GNSS/TOD module
            IRIG  adjustments from external IRIG-B signal
            DCF   adjustments from external DCF signal
            ====  =================================================

What: /sys/class/timecard/ocpN/available_sma_inputs Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Set of available destinations (sinks) for a SMA input signal.

            =====  ================================================
            10Mhz  signal is used as the 10Mhz reference clock
            PPS1   signal is sent to the PPS1 selector
            PPS2   signal is sent to the PPS2 selector
            TS1    signal is sent to timestamper 1
            TS2    signal is sent to timestamper 2
            TS3    signal is sent to timestamper 3
            TS4    signal is sent to timestamper 4
            IRIG   signal is sent to the IRIG-B module
            DCF    signal is sent to the DCF module
            FREQ1  signal is sent to frequency counter 1
            FREQ2  signal is sent to frequency counter 2
            FREQ3  signal is sent to frequency counter 3
            FREQ4  signal is sent to frequency counter 4
            None   signal input is disabled
            =====  ================================================

What: /sys/class/timecard/ocpN/available_sma_outputs Date: May 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Set of available sources for a SMA output signal.

            =====  ================================================
            10Mhz  output is from the 10Mhz reference clock
            PHC    output PPS is from the PHC clock
            MAC    output PPS is from the Miniature Atomic Clock
            GNSS1  output PPS is from the first GNSS module
            GNSS2  output PPS is from the second GNSS module
            IRIG   output is from the PHC, in IRIG-B format
            DCF    output is from the PHC, in DCF format
            GEN1   output is from frequency generator 1
            GEN2   output is from frequency generator 2
            GEN3   output is from frequency generator 3
            GEN4   output is from frequency generator 4
            GND    output is GND
            VCC    output is VCC
            =====  ================================================

What: /sys/class/timecard/ocpN/clock_source Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RW) Contains the current synchronization source used by the PHC. May be changed by writing one of the listed values from the available_clock_sources attribute set.

What: /sys/class/timecard/ocpN/clock_status_drift Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Contains the current drift value used by the firmware for internal disciplining of the atomic clock.

What: /sys/class/timecard/ocpN/clock_status_offset Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Contains the current offset value used by the firmware for internal disciplining of the atomic clock.

What: /sys/class/timecard/ocpN/freqX Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Optional directory containing the sysfs nodes for frequency counter .

What: /sys/class/timecard/ocpN/freqX/frequency Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Contains the measured frequency over the specified measurement period.

What: /sys/class/timecard/ocpN/freqX/seconds Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RW) Specifies the number of seconds from 0-255 that the frequency should be measured over. Write 0 to disable.

What: /sys/class/timecard/ocpN/genX Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Optional directory containing the sysfs nodes for frequency generator .

What: /sys/class/timecard/ocpN/genX/duty Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Specifies the signal duty cycle as a percentage from 1-99.

What: /sys/class/timecard/ocpN/genX/period Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Specifies the signal period in nanoseconds.

What: /sys/class/timecard/ocpN/genX/phase Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Specifies the signal phase offset in nanoseconds.

What: /sys/class/timecard/ocpN/genX/polarity Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Specifies the signal polarity, either 1 or 0.

What: /sys/class/timecard/ocpN/genX/running Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Either 0 or 1, showing if the signal generator is running.

What: /sys/class/timecard/ocpN/genX/start Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Shows the time in . that the signal generator started running.

What: /sys/class/timecard/ocpN/genX/signal Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RW) Used to start the signal generator, and summarize the current status.

	The signal generator may be started by writing the signal
	period, followed by the optional signal values.  If the
	optional values are not provided, they default to the current
	settings, which may be obtained from the other sysfs nodes.

	    period [duty [phase [polarity]]]

	echo 500000000 > signal       # 1/2 second period
	echo 1000000 40 100 > signal
	echo 0 > signal               # turn off generator

	Period and phase are specified in nanoseconds.  Duty cycle is
	a percentage from 1-99.  Polarity is 1 or 0.

	Reading this node will return:

	    period duty phase polarity start_time

What: /sys/class/timecard/ocpN/gnss_sync Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Indicates whether a valid GNSS signal is received, or when the signal was lost.

What: /sys/class/timecard/ocpN/i2c Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: This optional attribute links to the associated i2c device.

What: /sys/class/timecard/ocpN/irig_b_mode Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RW) An integer from 0-7 indicating the timecode format of the IRIG-B output signal: B00

What: /sys/class/timecard/ocpN/pps Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: This optional attribute links to the associated PPS device.

What: /sys/class/timecard/ocpN/ptp Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: This attribute links to the associated PTP device.

What: /sys/class/timecard/ocpN/serialnum Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RO) Provides the serial number of the timecard.

What: /sys/class/timecard/ocpN/sma1 What: /sys/class/timecard/ocpN/sma2 What: /sys/class/timecard/ocpN/sma3 What: /sys/class/timecard/ocpN/sma4 Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RW) These attributes specify the direction of the signal on the associated SMA connectors, and also the signal sink or source.

	The display format of the attribute is a space separated
	list of signals, prefixed by the input/output direction.

	The signal direction may be changed (if supported) by
	prefixing the signal list with either "in:" or "out:".
	If neither prefix is present, then the direction is unchanged.

	The output signal may be changed by writing one of the listed
	values from the available_sma_outputs attribute set.

	The input destinations may be changed by writing multiple
	values from the available_sma_inputs attribute set,
	separated by spaces.  If there are duplicated input
	destinations between connectors, the lowest numbered SMA
	connector is given priority.

	Note that not all input combinations may make sense.

	The 10Mhz reference clock input is currently only valid
	on SMA1 and may not be combined with other destination sinks.

What: /sys/class/timecard/ocpN/tod_correction Date: March 2022 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RW) The incoming GNSS signal is in UTC time, and the NMEA format messages do not provide a TAI offset. This sets the correction value for the incoming time.

	If UBX_LS is enabled, this should be 0, and the offset is
	taken from the UBX-NAV-TIMELS message.

What: /sys/class/timecard/ocpN/ts_window_adjust Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RW) When retrieving the PHC with the PTP SYS_OFFSET_EXTENDED ioctl, a system timestamp is made before and after the PHC time is retrieved. The midpoint between the two system timestamps is usually taken to be the SYS time associated with the PHC time. This estimate may be wrong, as it depends on PCI latencies, and when the PHC time was latched

	The attribute value reduces the end timestamp by the given
	number of nanoseconds, so the computed midpoint matches the
	retrieved PHC time.

	The initial value is set based on measured PCI latency and
	the estimated point where the FPGA latches the PHC time.  This
	value may be changed by writing an unsigned integer.

What: /sys/class/timecard/ocpN/ttyGNSS What: /sys/class/timecard/ocpN/ttyGNSS2 Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: These optional attributes link to the TTY serial ports associated with the GNSS devices.

What: /sys/class/timecard/ocpN/ttyMAC Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: This optional attribute links to the TTY serial port associated with the Miniature Atomic Clock.

What: /sys/class/timecard/ocpN/ttyNMEA Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: This optional attribute links to the TTY serial port which outputs the PHC time in NMEA ZDA format.

What: /sys/class/timecard/ocpN/utc_tai_offset Date: September 2021 Contact: Jonathan Lemon jonathan.lemon@gmail.com Description: (RW) The DCF and IRIG output signals are in UTC, while the TimeCard operates on TAI. This attribute allows setting the offset in seconds, which is added to the TAI timebase for these formats.

	The offset may be changed by writing an unsigned integer.