[PATCH] iio: invensense: fix interrupt timestamp alignment

[inv.git-commit@tdk.com]

From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>

Restrict interrupt timestamp alignment for not overflowing max/min
period thresholds.

Fixes: 0ecc363ccea7 ("iio: make invensense timestamp module generic")
Cc: stable@vger.kernel.org
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
---
 drivers/iio/common/inv_sensors/inv_sensors_timestamp.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c b/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
index 3b0f9598a7c7..4b8ec16240b5 100644
--- a/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
+++ b/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
@@ -101,6 +101,9 @@ static bool inv_update_chip_period(struct inv_sensors_timestamp *ts,

 static void inv_align_timestamp_it(struct inv_sensors_timestamp *ts)
 {
+	const int64_t period_min = ts->min_period * ts->mult;
+	const int64_t period_max = ts->max_period * ts->mult;
+	int64_t add_max, sub_max;
 	int64_t delta, jitter;
 	int64_t adjust;

@@ -108,11 +111,13 @@ static void inv_align_timestamp_it(struct inv_sensors_timestamp *ts)
 	delta = ts->it.lo - ts->timestamp;

 	/* adjust timestamp while respecting jitter */
+	add_max = period_max - (int64_t)ts->period;
+	sub_max = period_min - (int64_t)ts->period;
 	jitter = INV_SENSORS_TIMESTAMP_JITTER((int64_t)ts->period, ts->chip.jitter);
 	if (delta > jitter)
-		adjust = jitter;
+		adjust = add_max;
 	else if (delta < -jitter)
-		adjust = -jitter;
+		adjust = sub_max;
 	else
 		adjust = 0;

--
2.34.1