[PATCH net-next v4 0/6] eth: fbnic: expand hwmon sensor support

[Zinc Lim]

The firmware capability response carries per-board sensor thresholds,
and the firmware reports which range a sensor has entered whenever it
crosses one of them. This series surfaces both to userspace:

 - Move the sensor read logic out of fbnic_mac, closer to its only
   caller in the hwmon code, and drop the now-unused get_sensor op.
 - Cache the temperature and voltage readings for the current jiffy so
   a burst of attribute reads issues a single firmware round-trip.
 - Parse and expose the temperature (min/max/crit) and voltage
   (min/max) thresholds. Thresholds the firmware does not report are
   not exposed.
 - Parse the range firmware reports, both in the unsolicited threshold
   event and in the sensor read response, and cache it per sensor.
 - Expose temp1_alarm and in0_alarm from that cached range, and notify
   on each crossing through hwmon_notify_event().
 - Derive the range from the reading carried with the event, on old
   firmware that predates range reporting.

Changes from v3:
 - Moved cache seeding to fbnic_mbx_init() in patch 2, so it also runs
   on resume and AER recovery paths rather than only on probe.
 - Dropped previous patch exposing all hwmon attributes unconditionally as
   read-only. Thresholds the firmware does not report are now not visible
   in sysfs.
 - Collapsed the five per-threshold alarm attributes
   (temp1_{min,max,crit}_alarm, in0_{min,max}_alarm) into one alarm per
   sensor, temp1_alarm and in0_alarm. Firmware reports which range a
   sensor is in rather than per-limit flags, so a single attribute
   matches what the hardware reports.
 - That alarm now comes from the reported range rather than from a
   driver-side comparison of a live reading against the thresholds.
 - Split the alarm work into two: patch 4 parses and caches the range,
   from both the unsolicited event and the sensor read response, and
   patch 5 exposes the attributes and notifies on each crossing. The
   previous "firmware notifies hwmon on sensor threshold events" patch 6
   is now folded into those.
 - Added patch 6 for firmware that predates range reporting, which
   flags only that a limit was exceeded.

Changes from v2:
 - Addressed Jakub's patch 3 feedback on jiffy comparison when
   checking cache validity.

Changes from v1:
 - Addressed Jakub's patch 6 feedback on including a
   if (!IS_REACHABLE(CONFIG_HWMON)) return; guard.

Zinc Lim (6):
  eth: fbnic: move sensor read logic out of fbnic_mac
  eth: fbnic: cache hwmon sensor readings
  eth: fbnic: report temperature and voltage thresholds via hwmon
  eth: fbnic: parse the alarm range reported by firmware
  eth: fbnic: report temperature and voltage alarms via hwmon
  eth: fbnic: derive the alarm range on older firmware

 drivers/net/ethernet/meta/fbnic/fbnic.h       |  11 +
 drivers/net/ethernet/meta/fbnic/fbnic_fw.c    | 140 +++++++-
 drivers/net/ethernet/meta/fbnic/fbnic_fw.h    |  44 +++
 drivers/net/ethernet/meta/fbnic/fbnic_hwmon.c | 332 ++++++++++++++++--
 drivers/net/ethernet/meta/fbnic/fbnic_mac.c   |  55 ---
 drivers/net/ethernet/meta/fbnic/fbnic_mac.h   |   2 -
 6 files changed, 500 insertions(+), 84 deletions(-)

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2.53.0-Meta