diff --git a/drivers/staging/comedi/drivers/comedi_test.c b/drivers/staging/comedi/drivers/comedi_test.c
index 8845075cd3cc..4d4358ce1710 100644
--- a/drivers/staging/comedi/drivers/comedi_test.c
+++ b/drivers/staging/comedi/drivers/comedi_test.c
@@ -52,13 +52,14 @@ zero volts).
 
 #include "comedi_fc.h"
 #include <linux/timer.h>
+#include <linux/ktime.h>
 
 #define N_CHANS 8
 
 /* Data unique to this driver */
 struct waveform_private {
 	struct timer_list timer;
-	struct timeval last;		/* time last timer interrupt occurred */
+	ktime_t last;	/* time last timer interrupt occurred */
 	unsigned int uvolt_amplitude;	/* waveform amplitude in microvolts */
 	unsigned long usec_period;	/* waveform period in microseconds */
 	unsigned long usec_current;	/* current time (mod waveform period) */
@@ -171,14 +172,12 @@ static void waveform_ai_interrupt(unsigned long arg)
 	/* all times in microsec */
 	unsigned long elapsed_time;
 	unsigned int num_scans;
-	struct timeval now;
+	ktime_t now;
 	bool stopping = false;
 
-	do_gettimeofday(&now);
+	now = ktime_get();
 
-	elapsed_time =
-	    1000000 * (now.tv_sec - devpriv->last.tv_sec) + now.tv_usec -
-	    devpriv->last.tv_usec;
+	elapsed_time = ktime_to_us(ktime_sub(now, devpriv->last));
 	devpriv->last = now;
 	num_scans =
 	    (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
@@ -317,8 +316,9 @@ static int waveform_ai_cmd(struct comedi_device *dev,
 	else	/* TRIG_TIMER */
 		devpriv->convert_period = cmd->convert_arg / nano_per_micro;
 
-	do_gettimeofday(&devpriv->last);
-	devpriv->usec_current = devpriv->last.tv_usec % devpriv->usec_period;
+	devpriv->last = ktime_get();
+	devpriv->usec_current =
+		((u32)ktime_to_us(devpriv->last)) % devpriv->usec_period;
 	devpriv->usec_remainder = 0;
 
 	devpriv->timer.expires = jiffies + 1;