diff --git a/src/drivers/kinetis/drv_hrt.c b/src/drivers/kinetis/drv_hrt.c
index 3b0ea70468..b103d791ec 100644
--- a/src/drivers/kinetis/drv_hrt.c
+++ b/src/drivers/kinetis/drv_hrt.c
@@ -572,7 +572,7 @@ hrt_absolute_time(void)
  * Convert a timespec to absolute time
  */
 hrt_abstime
-ts_to_abstime(struct timespec *ts)
+ts_to_abstime(const struct timespec *ts)
 {
 	hrt_abstime	result;
 
diff --git a/src/drivers/samv7/drv_hrt.c b/src/drivers/samv7/drv_hrt.c
index d1adc7ae24..b067d9cfe5 100644
--- a/src/drivers/samv7/drv_hrt.c
+++ b/src/drivers/samv7/drv_hrt.c
@@ -653,7 +653,7 @@ hrt_absolute_time(void)
  * Convert a timespec to absolute time
  */
 hrt_abstime
-ts_to_abstime(struct timespec *ts)
+ts_to_abstime(const struct timespec *ts)
 {
 	hrt_abstime	result;
 
diff --git a/src/drivers/stm32/drv_hrt.c b/src/drivers/stm32/drv_hrt.c
index 4fc6d1f220..6fcbbf8e36 100644
--- a/src/drivers/stm32/drv_hrt.c
+++ b/src/drivers/stm32/drv_hrt.c
@@ -694,7 +694,7 @@ hrt_absolute_time(void)
  * Convert a timespec to absolute time
  */
 hrt_abstime
-ts_to_abstime(struct timespec *ts)
+ts_to_abstime(const struct timespec *ts)
 {
 	hrt_abstime	result;