RE: [Intel-wired-lan] [PATCH v3 iwl-next 2/3] ice: add TSPLL DPLL device and TIME_REF pin for E825

[Nowlin, Alexander]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of Grzegorz Nitka
> Sent: Monday, August 3, 2026 4:35 AM
> To: intel-wired-lan@xxxxxxxxxxxxxxxx
> Cc: Kitszel, Przemyslaw <przemyslaw.kitszel@xxxxxxxxx>; richardcochran@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Kubalewski, Arkadiusz <arkadiusz.kubalewski@xxxxxxxxx>; Korba, Przemyslaw <przemyslaw.korba@xxxxxxxxx>; andrew+netdev@xxxxxxx; edumazet@xxxxxxxxxx; Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; netdev@xxxxxxxxxxxxxxx; kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; davem@xxxxxxxxxxxxx
> Subject: [Intel-wired-lan] [PATCH v3 iwl-next 2/3] ice: add TSPLL DPLL device and TIME_REF pin for E825
> 
> This extends the E825 advanced sync-timing support introduced by the tx-clk series, which added the TXC DPLL device for TX reference clock control. The TSPLL, the source timer PLL, is now also exposed through > the dpll subsystem so that its lock status and clock source selection are visible and controllable from userspace.
> 
> On E825 devices the TSPLL is the source timer PLL, distinct from the EEC and PPS DPLLs used on E810. Register it as a DPLL_TYPE_GENERIC device for owner PFs.
> 
> Add struct ice_dplls::tspll_in, a fwnode-backed input pin named "time_ref". The state_on_dpll_get callback queries ICE_CGU_R23 via
> ice_tspll_get_clk_src() and returns CONNECTED when TIME_REF is selected as clock source, DISCONNECTED otherwise. The state_on_dpll_set callback switches the source between TIME_REF and TCXO via the new
> ice_tspll_set_cfg() helper. Registration is deferred via the dpll notifier path if the pin is not yet visible in the subsystem at probe time.
> 
> Initialize TSPLL DPLL state from direct clock-source/lock reads so the first published state reflects hardware and prev_dpll_state matches.
> During periodic polling, the DPLL worker consumes READ_ONCE(pf->ptp.tspll_locked), maintained and recovered by the PTP periodic worker. When the TSPLL clock source is TCXO (TIME_REF pin not selected), UNLOCKED is reported unconditionally to reflect the free-running state of the oscillator regardless of the raw lock bit.
> To avoid stale lock-status reads after synchronous source changes, the set callback now refreshes tspll.dpll_state immediately and emits a DPLL change notification when the cached state changed.
> 
> If a TSPLL reconfiguration is applied but the PLL has not yet re-acquired lock, treat the internal -EAGAIN result as success so the PTP periodic worker can complete recovery, while real -EBUSY failures from reset/SBQ paths still propagate to userspace.
> 
> The TSPLL userspace reconfiguration path (state_on_dpll_set) and the PTP periodic worker (ice_ptp_tspll_monitor) both read TSPLL HW state and write the pf->ptp.tspll_locked cache consumed by the DPLL worker.
> Serialize both with pf->dplls.lock across their HW-read -> cache-write sequence; otherwise a preempted monitor could overwrite an accurate cache update from the DPLL callback with stale HW state. The mutex > lifetime is lifted to PF-features scope (initialized in
> ice_init_features() before ice_ptp_init(), destroyed in
> ice_deinit_features() after ice_ptp_release()) so the PTP monitor can take it unconditionally regardless of DPLL init state.
> 
> Extend ice_dpll_deinit_txclk_pins() with a "flush" parameter so the
> E825 init error path for the TSPLL fwnode pin can tear down TXCLK pins without flushing pf->dplls.wq. If the flush ran here, notifier work items queued during earlier init steps would be blocked on
> pf->dplls.dpll_init, which is only completed at the unregister_pins
> label reached after this teardown. destroy_workqueue() at that label drains the queued items safely. Existing full-teardown callers pass flush=true and keep current behavior.
> 
> Reviewed-by: Przemyslaw Korba <przemyslaw.korba@xxxxxxxxx>
> Signed-off-by: Grzegorz Nitka <grzegorz.nitka@xxxxxxxxx>
> ---
>  drivers/net/ethernet/intel/ice/ice_dpll.c  | 420 ++++++++++++++++++---
>  drivers/net/ethernet/intel/ice/ice_dpll.h  |   4 +
>  drivers/net/ethernet/intel/ice/ice_main.c  |   9 +
>  drivers/net/ethernet/intel/ice/ice_ptp.c   |  12 +
>  drivers/net/ethernet/intel/ice/ice_tspll.c |  34 +-
>  drivers/net/ethernet/intel/ice/ice_tspll.h |   2 +
>  6 files changed, 426 insertions(+), 55 deletions(-)

Tested-by: Alexander Nowlin <alexander.nowlin@xxxxxxxxx>