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Diffstat (limited to 'Documentation/driver-api/ptp.rst')
-rw-r--r-- | Documentation/driver-api/ptp.rst | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/driver-api/ptp.rst b/Documentation/driver-api/ptp.rst index a15192e32347..5e033c3b11b3 100644 --- a/Documentation/driver-api/ptp.rst +++ b/Documentation/driver-api/ptp.rst @@ -23,6 +23,7 @@ PTP hardware clock infrastructure for Linux + Ancillary clock features - Time stamp external events - Period output signals configurable from user space + - Low Pass Filter (LPF) access from user space - Synchronization of the Linux system time via the PPS subsystem PTP hardware clock kernel API @@ -72,6 +73,22 @@ Writing clock drivers class driver, since the lock may also be needed by the clock driver's interrupt service routine. +PTP hardware clock requirements for '.adjphase' +----------------------------------------------- + + The 'struct ptp_clock_info' interface has a '.adjphase' function. + This function has a set of requirements from the PHC in order to be + implemented. + + * The PHC implements a servo algorithm internally that is used to + correct the offset passed in the '.adjphase' call. + * When other PTP adjustment functions are called, the PHC servo + algorithm is disabled. + + **NOTE:** '.adjphase' is not a simple time adjustment functionality + that 'jumps' the PHC clock time based on the provided offset. It + should correct the offset provided using an internal algorithm. + Supported hardware ================== @@ -94,3 +111,27 @@ Supported hardware - Auxiliary Slave/Master Mode Snapshot (optional interrupt) - Target Time (optional interrupt) + + * Renesas (IDT) ClockMatrix™ + + - Up to 4 independent PHC channels + - Integrated low pass filter (LPF), access via .adjPhase (compliant to ITU-T G.8273.2) + - Programmable output periodic signals + - Programmable inputs can time stamp external triggers + - Driver and/or hardware configuration through firmware (idtcm.bin) + - LPF settings (bandwidth, phase limiting, automatic holdover, physical layer assist (per ITU-T G.8273.2)) + - Programmable output PTP clocks, any frequency up to 1GHz (to other PHY/MAC time stampers, refclk to ASSPs/SoCs/FPGAs) + - Lock to GNSS input, automatic switching between GNSS and user-space PHC control (optional) + + * NVIDIA Mellanox + + - GPIO + - Certain variants of ConnectX-6 Dx and later products support one + GPIO which can time stamp external triggers and one GPIO to produce + periodic signals. + - Certain variants of ConnectX-5 and older products support one GPIO, + configured to either time stamp external triggers or produce + periodic signals. + - PHC instances + - All ConnectX devices have a free-running counter + - ConnectX-6 Dx and later devices have a UTC format counter |