Merge branch 'net-stmmac-use-correct-pps-input-indexing'

Merge branch 'net-stmmac-use-correct-pps-input-indexing'

Johannes Zink says:

====================
net: stmmac: use correct PPS input indexing

The stmmac can have 0 to 4 auxiliary snapshot in channels, which can be
used for capturing external triggers with respect to the eqos PTP timer.

Previously when enabling the auxiliary snapshot, an invalid request was
written to the hardware register, except for the Intel variant of this
driver, where the only snapshot available was hardcoded.

Patch 1 of this series cleans up the debug netdev_dbg message indicating
the auxiliary snapshot being {en,dis}abled. No functional changes here

Patch 2 of this series writes the correct PPS input indexing to the
hardware registers instead of a previously used fixed value

Patch 3 of this series removes a field member from plat_stmmacnet_data
that is no longer needed

Patch 4 of this series prepares Patch 5 by protecting the snapshot
enabled flag by the aux_ts_lock mutex

Patch 5 of this series adds a temporary workaround, since at the moment
the driver can handle only one single auxiliary snapshot at a time.
Previously the driver silently dropped the previous configuration and
enabled the new one. Now, if a snapshot is already enabled and userspace
tries to enable another without previously disabling the snapshot currently
enabled: issue a netdev_err and return an errorcode indicating the device is
busy.

This series is a "never worked, doesn't hurt anyone" touchup to the PPS
capture for non-intel variants of the dwmac driver.
====================

Link: https://lore.kernel.org/r/20231010-stmmac_fix_auxiliary_event_capture-v2-0-51d5f56542d7@pengutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>