hwmon: (pmbus) Clear generic status alarms with CLEAR_FAULTS

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Some hwmon alarms fall back to STATUS_WORD summary bits when no
individual limit alarm is available. On PMBus 1.2 and newer devices,
pmbus_get_boolean() acknowledges these alarms with the same byte-data
write used for detailed status registers. For example, PB_STATUS_INPUT
is 0x2000, so it is truncated to zero when passed to
_pmbus_write_byte_data(). The resulting write cannot acknowledge the
input alarm.

PMBus 1.3 Part II, sections 10.2.4 and 10.2.5, excludes ordinary
STATUS_BYTE and STATUS_WORD summary bits from individual clearing.
Their summary bits clear when the underlying status bits clear, so
changing this to a word-data write would not fix the generic input
alarm either.

Use the existing page CLEAR_FAULTS path for generic STATUS_WORD
alarms, including devices whose status accessor uses STATUS_BYTE.
Keep individual byte writes for detailed status registers on PMBus
1.2 and newer devices. As with the existing older-device fallback,
CLEAR_FAULTS can clear other latched status; an active condition can
reassert its status.

Fixes: 35f165f089 ("hwmon: (pmbus) Clear pmbus fault/warning bits after read")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Vishnu Razdan <vrazdan@openai.com>
Link: https://patch.msgid.link/20260824-vrazdan-pmbus-status-word-b4-v1-1-2606ecd0c029@openai.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

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Vishnu Razdan 2026-08-24 23:58:00 -07:00 • committed by Guenter Roeck

parent 286b175bb0

commit 6d760f8b41

1 changed files with 3 additions and 1 deletions

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drivers/hwmon/pmbus/pmbus_core.c

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