hwmon: (pmbus) Fix passing events to regulator core

Sashiko reports:

Commit 754bd2b4a084 ("hwmon: (pmbus/core) Protect regulator operations with
mutex") introduced a worker to batch regulator events over time using
atomic_or(). The delayed worker then passes the combined bitmask unmodified
to regulator_notifier_call_chain().

The core regulator subsystem's regulator_handle_critical() function
evaluates the event parameter using a strict switch statement. If
multiple distinct faults occur before the worker runs (e.g.,
REGULATOR_EVENT_UNDER_VOLTAGE | REGULATOR_EVENT_OVER_CURRENT), the combined
bitmask fails to match any case. This leaves the reason as NULL and
completely bypasses the critical hw_protection_trigger().

Fix the problem by passing events bit by bit to the regulator event
handler.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Fixes: 754bd2b4a084 ("hwmon: (pmbus/core) Protect regulator operations with mutex")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 8123a568af40..3143b9e0316c 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -3347,18 +3347,23 @@ static void pmbus_regulator_notify_worker(struct work_struct *work)
 	int i, j;
 
 	for (i = 0; i < data->info->pages; i++) {
-		int event;
+		unsigned int event;
 
 		event = atomic_xchg(&data->regulator_events[i], 0);
 		if (!event)
 			continue;
 
 		for (j = 0; j < data->info->num_regulators; j++) {
-			if (i == rdev_get_id(data->rdevs[j])) {
+			if (i != rdev_get_id(data->rdevs[j]))
+				continue;
+			while (event) {
+				unsigned int _event = BIT(__ffs(event));
+
 				regulator_notifier_call_chain(data->rdevs[j],
-							      event, NULL);
-				break;
+							      _event, NULL);
+				event &= ~_event;
 			}
+			break;
 		}
 	}
 }