iio: imu: inv_icm42600: fix timestamp reset

Timestamp reset is not done in the correct place. It must be done
before enabling buffer. The reason is that interrupt timestamping
is always happening when the chip is on, even if the
corresponding sensor is off. When the sensor restarts, timestamp
is wrong if you don't do a reset first.

Fixes: ec74ae9fd3 ("iio: imu: inv_icm42600: add accurate timestamping")
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20230509152202.245444-1-inv.git-commit@tdk.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c

@@ -275,9 +275,14 @@ static int inv_icm42600_buffer_preenable(struct iio_dev *indio_dev)
 {
 	struct inv_icm42600_state *st = iio_device_get_drvdata(indio_dev);
 	struct device *dev = regmap_get_device(st->map);
+	struct inv_icm42600_timestamp *ts = iio_priv(indio_dev);
 
 	pm_runtime_get_sync(dev);
 
+	mutex_lock(&st->lock);
+	inv_icm42600_timestamp_reset(ts);
+	mutex_unlock(&st->lock);
+
 	return 0;
 }
 
@@ -375,7 +380,6 @@ static int inv_icm42600_buffer_postdisable(struct iio_dev *indio_dev)
 	struct device *dev = regmap_get_device(st->map);
 	unsigned int sensor;
 	unsigned int *watermark;
-	struct inv_icm42600_timestamp *ts;
 	struct inv_icm42600_sensor_conf conf = INV_ICM42600_SENSOR_CONF_INIT;
 	unsigned int sleep_temp = 0;
 	unsigned int sleep_sensor = 0;
@@ -385,11 +389,9 @@ static int inv_icm42600_buffer_postdisable(struct iio_dev *indio_dev)
 	if (indio_dev == st->indio_gyro) {
 		sensor = INV_ICM42600_SENSOR_GYRO;
 		watermark = &st->fifo.watermark.gyro;
-		ts = iio_priv(st->indio_gyro);
 	} else if (indio_dev == st->indio_accel) {
 		sensor = INV_ICM42600_SENSOR_ACCEL;
 		watermark = &st->fifo.watermark.accel;
-		ts = iio_priv(st->indio_accel);
 	} else {
 		return -EINVAL;
 	}
@@ -417,8 +419,6 @@ static int inv_icm42600_buffer_postdisable(struct iio_dev *indio_dev)
 	if (!st->fifo.on)
 		ret = inv_icm42600_set_temp_conf(st, false, &sleep_temp);
 
-	inv_icm42600_timestamp_reset(ts);
-
 out_unlock:
 	mutex_unlock(&st->lock);