drivers: sensor: bmm350: expose magnetic reset

This exposes a driver specific function to perform a
magentic reset by the application.

Signed-off-by: Ryan McClelland <ryanmcclelland@meta.com>

drivers/sensor/bosch/bmm350/bmm350.c

@@ -349,7 +349,7 @@ static int bmm350_set_powermode(const struct device *dev, enum bmm350_power_mode
  * used to perform the magnetic reset of the sensor
  * which is necessary after a field shock ( 400mT field applied to sensor )
  */
-static int bmm350_magnetic_reset_and_wait(const struct device *dev)
+int bmm350_magnetic_reset(const struct device *dev)
 {
 	/* Variable to store the function result */
 	int ret = 0;
@@ -1005,7 +1005,7 @@ static int bmm350_init_chip(const struct device *dev)
 		goto err_poweroff;
 	}
 
-	ret = bmm350_magnetic_reset_and_wait(dev);
+	ret = bmm350_magnetic_reset(dev);
 	if (ret != 0) {
 		LOG_ERR("failed to perform magnetic reset");
 		goto err_poweroff;

include/zephyr/drivers/sensor/bmm350.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2025 Meta Platforms
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @brief Performs a magnetic reset.
+ *
+ * The BMM350 has measures to recover from excessively strong
+ * magnetic fields. A magnetic reset is trigged after reset by
+ * the device itself, but if excessive field exposure has occurred
+ * in suspend mode, the sensor can not detect that event. If a
+ * large offset or sensitvity drift indicates that such an event
+ * has occurred, then this function can be called by the
+ * application.
+ *
+ * "Enhanced" Magnetic Reset supported by later BMM350 Revisions
+ * is not yet implemented.
+ *
+ * @param dev Pointer to the sensor device
+ *
+ * @return 0 if successful, negative errno code if failure.
+ */
+int bmm350_magnetic_reset(const struct device *dev);