[PATCH net-next v8 0/3] dpll: zl3073x: add PTP clock support

Add PTP hardware clock support to the zl3073x DPLL driver.

Patch 1 scales the poll sleep interval in zl3073x_poll_zero_u8()
proportionally to the timeout to avoid excessive bus traffic for
the longer PTP-related timeouts.

Patch 2 adds low-level channel operations for ToD read/write/adjust,
output phase step, delta frequency offset write and TIE write as
building blocks for PTP callbacks.

Patch 3 registers a PTP clock device for each DPLL channel with
gettimex64, settime64, adjtime, adjfine, adjphase and getmaxphase
callbacks. Callback availability adapts to the current channel
state - adjfine requires NCO pin connected, adjphase uses TIE write
when tracking a reference, and adjtime selects the appropriate
mechanism automatically. Periodic output support will be added in a
follow-up series.

Link: https://lore.kernel.org/netdev/[email protected]/
Link: https://lore.kernel.org/netdev/[email protected]/
Link: https://lore.kernel.org/netdev/[email protected]/
Link: https://lore.kernel.org/netdev/[email protected]/
Link: https://lore.kernel.org/netdev/[email protected]/
Link: https://lore.kernel.org/netdev/[email protected]/

Changes:
v8:
  - Drop WARN_ON from tod_ready_wait default case and drop tie_write
    range guard entirely (Vadim)
  - Use timespec64_valid_settod() in tod_adjust (Vadim)
v7:
  - Check SEM bit before CMD in tod_ready_wait so stale CMD bits
    from a prior boot stage do not block ToD operations
  - Move ptp_info template assignment from alloc to register to
    avoid stale getcycles64 pointers on devlink reload
  - Update kernel-doc for tod_ready_wait, adjtime, adjtime_phase_step
    and tie_write to match actual return semantics
  - Update poll interval changelog to mention effect on all callers
v6:
  - Fix kernel-doc warning: move ZL_TOD_MAX_RETRIES define inside
    the function body to avoid confusing the kernel-doc parser
v5:
  - Add prep patch to scale poll interval with timeout
  - Enumerate all ToD commands in tod_ready_wait switch, return
    -EOPNOTSUPP with WARN_ON in default case (Vadim)
  - Handle CMD=0 (power-on default) in tod_ready_wait
  - Rewrite tod_adjust rollover guard as a retry loop that re-reads
    until the margin is sufficient, replacing manual fixup and fsleep
  - Fix "lowest-ID synth" comments to "first enabled synth"
  - Include dev_name() in PTP clock name for multi-device systems
  - Update kernel-doc for adjfine/adjphase to document zero no-op
v4:
  - Move out_step_time_mask to struct zl3073x_dev (device-global)
  - Fix tod_adjust rollover guard for tick-crossing case
  - Drop trailing tod_ready_wait from tod_adjust
  - Fix TOD_CTRL register item count
  - Move phase step registers into existing page 9 section in regs.h
  - Align ToD command define values
  - Update kernel-doc for chan_state_fetch
  - Drop perout support (will rework as follow-up)
  - Replace abs(delta) with explicit range check to avoid S64_MIN UB
  - Add locking context doc to zl3073x_chan_df_offset_set
  - Export zl3073x_chan_tod_ready_wait and wait for ToD completion in
    adjtime before phase step/TIE write to prevent WR_NEXT_1HZ from
    overwriting the sub-second adjustment
v3:
  - Use PTP_1588_CLOCK instead of PTP_1588_CLOCK_OPTIONAL (Jakub)
  - Factor out output pin frequency helper to a separate commit (Jakub)
  - Remove spurious #include <linux/mutex.h> from dpll.h (Jakub)
v2:
  - Squash low-level ops patches (1+3) into patch 1.
  - Squash PTP callback patches (2+4) into patch 2, register PTP
    clock regardless of initial channel state.

Ivan Vecera (3):
  dpll: zl3073x: scale poll interval proportionally to timeout
  dpll: zl3073x: add channel ToD, phase step and TIE operations
  dpll: zl3073x: add PTP clock support

 drivers/dpll/zl3073x/Kconfig |   6 +-
 drivers/dpll/zl3073x/chan.c  | 321 ++++++++++++++++++++++++-
 drivers/dpll/zl3073x/chan.h  |  32 +++
 drivers/dpll/zl3073x/core.c  |  17 +-
 drivers/dpll/zl3073x/core.h  |  23 ++
 drivers/dpll/zl3073x/dpll.c  | 439 +++++++++++++++++++++++++++++++++--
 drivers/dpll/zl3073x/dpll.h  |   5 +
 drivers/dpll/zl3073x/regs.h  |  52 +++++
 8 files changed, 863 insertions(+), 32 deletions(-)


base-commit: 4f93b12cf7b25fbf8e73d222722805b049f0a6d3
-- 
2.54.0