Add support for the Monolithic Power Systems MPQ8646 step-down
converter as a PMBus device.
1/3 pmbus core: add and export pmbus_get_hwmon_device() so a chip
driver can call hwmon_notify_event() from an in-driver
alarm-poll fallback (lm90-style) on boards where the chip's
SMBALERT# pin is unavailable to the CPU.
2/3 dt-bindings: the MPQ8646 binding; schema inspired from the
mpq8785 (same mps,vout-fb-divider-ratio-permille property).
3/3 the MPQ8646 driver: PMBus telemetry plus MFR_CFG_EXT
gate-close retry after CLEAR_LAST_FAULT, alarm acknowledge via
inX_reset_history, MPS-extended STATUS_WORD decode and
post-mortem clear, the alarm-poll fallback for boards without
SMBALERT, and on_off_config / vout_margin / mfr_pmbus_lock
sysfs.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
Changes in v5:
- driver: fix the hwmon channel indices used by the in*_alarm poll
notifications (thanks Sashiko AI, v4)
- driver: remove the shared debugfs root on module unload, by creating
it in module_init() and removing it in module_exit(). It also drops
the v4 per-probe root mutex and debugfs_lookup()
(Sashiko AI review of v4)
- doc: add Documentation/hwmon/mpq8646.rst to the toctree (kernel test robot)
- doc: fix a malformed table and drop the stale probe_page_write row
(removed since v3) and fix typo
- Link to v4: https://lore.kernel.org/r/20260723-mpq8646_v0-v4-0-b6323d5fc524@free.fr
Changes in v4 (all reported by the Sashiko AI review on v3):
- driver: register debugfs only after a successful pmbus_do_probe() --
the debugfs handlers take pmbus_lock() and rely on the pmbus clientdata
that pmbus_do_probe() installs (NULL-deref window in v3)
- driver: in remove(), unregister debugfs before cancel_delayed_work_sync()
so a debugfs write cannot re-arm the poll worker after it is cancelled
- driver: serialise the shared debugfs root create against concurrent
probes with a static mutex
- driver: move the remaining last_probe_* updates (clear_protection_last,
store_all, restore_all) inside mps_lock
- dt-bindings: describe the hardware, not the driver, in the description
- Link to v3: https://lore.kernel.org/r/20260723-mpq8646_v0-v3-0-1af1f3d38848@free.fr
Changes in v3 (all reported by the Sashiko AI review on v2):
- driver: alarm_poll_interval_ms is now a debugfs fops
- driver: pmbus_lock() around the async raw i2c accesses: the poll
worker and the CLEAR_LAST_FAULT force sequence, the nvmem snapshot read
keeps mps_lock (read-only, no chip-state change)
- driver: update last_probe_rc/last_probe_data under mps_lock to avoid
torn diagnostics
- driver: remove the dead PMBUS_PAGE swallow in write_byte
- driver: remove the probe_page_write debugfs hook
- Link to v2: https://lore.kernel.org/r/20260723-mpq8646_v0-v2-0-3c4cb71f23c0@free.fr
Changes in v2:
- driver: register debugfs only after the DT-property validation, to
avoid an early probe error to avoid dangling debugfs entries
- driver: do not schedule the alarm-poll worker when SMBALERT# (irq)
is wired, and do not re-arm it from the worker in that case
- driver: dput() the dentry returned by debugfs_lookup()
- driver: hold mps_lock around the nvmem snapshot reads
- driver: fix VID coefficients comment
- dt-bindings: fix typo of the commit message
- Link to v1: https://lore.kernel.org/r/20260723-mpq8646_v0-v1-0-14363c75916f@free.fr
---
Vincent Jardin (3):
hwmon: pmbus: event notification with alarms
dt-bindings: hwmon: pmbus: add MPS MPQ8646 binding
hwmon: pmbus: add MPQ8646 driver
.../bindings/hwmon/pmbus/mps,mpq8646.yaml | 50 +
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/mpq8646.rst | 313 +++++
MAINTAINERS | 8 +
drivers/hwmon/pmbus/Kconfig | 11 +
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/mpq8646.c | 1253 ++++++++++++++++++++
drivers/hwmon/pmbus/pmbus.h | 1 +
drivers/hwmon/pmbus/pmbus_core.c | 8 +
9 files changed, 1646 insertions(+)
---
base-commit: 248951ddc14de84de3910f9b13f51491a8cd91df
change-id: 20260723-mpq8646_v0-3383cb574d7a
Best regards,
--
Vincent Jardin <vjardin@free.fr>