| 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 |
| IRIG signal is sent to the IRIG-B module |
| DCF signal is sent to the DCF module |
| ===== ================================================ |
| |
| 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 |
| GNSS output PPS is from the 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 |
| ===== ================================================ |
| |
| 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/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<n> |
| |
| 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/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. |
