diff --git a/drivers/staging/comedi/drivers/rtd520.c b/drivers/staging/comedi/drivers/rtd520.c
index 28402d2f92a2e9efc94212349baf66e57ac17b29..d55c5893203ba3a6be29a9d63ef5012e13b7d5e2 100644
--- a/drivers/staging/comedi/drivers/rtd520.c
+++ b/drivers/staging/comedi/drivers/rtd520.c
@@ -779,7 +779,7 @@ static int rtd_ai_cmdtest(struct comedi_device *dev,
 			  struct comedi_subdevice *s, struct comedi_cmd *cmd)
 {
 	int err = 0;
-	int tmp;
+	unsigned int arg;
 
 	/* Step 1 : check if triggers are trivially valid */
 
@@ -894,26 +894,20 @@ static int rtd_ai_cmdtest(struct comedi_device *dev,
 	/* step 4: fix up any arguments */
 
 	if (cmd->scan_begin_src == TRIG_TIMER) {
-		tmp = cmd->scan_begin_arg;
-		rtd_ns_to_timer(&cmd->scan_begin_arg,
-				cmd->flags & TRIG_ROUND_MASK);
-		if (tmp != cmd->scan_begin_arg)
-			err++;
-
+		arg = cmd->scan_begin_arg;
+		rtd_ns_to_timer(&arg, cmd->flags & TRIG_ROUND_MASK);
+		err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
 	}
+
 	if (cmd->convert_src == TRIG_TIMER) {
-		tmp = cmd->convert_arg;
-		rtd_ns_to_timer(&cmd->convert_arg,
-				cmd->flags & TRIG_ROUND_MASK);
-		if (tmp != cmd->convert_arg)
-			err++;
-
-		if (cmd->scan_begin_src == TRIG_TIMER
-		    && (cmd->scan_begin_arg
-			< (cmd->convert_arg * cmd->scan_end_arg))) {
-			cmd->scan_begin_arg =
-			    cmd->convert_arg * cmd->scan_end_arg;
-			err++;
+		arg = cmd->convert_arg;
+		rtd_ns_to_timer(&arg, cmd->flags & TRIG_ROUND_MASK);
+		err |= cfc_check_trigger_arg_is(&cmd->convert_arg, arg);
+
+		if (cmd->scan_begin_src == TRIG_TIMER) {
+			arg = cmd->convert_arg * cmd->scan_end_arg;
+			err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
+							 arg);
 		}
 	}