staging: comedi: das16m1: use comedi_fc helpers to validate timer args

Use the comedi_fc helper cfc_check_trigger_arg_is() to validate the
trigger arguments when the source is TRIG_TIMER.

For aesthetics, rename the local variable 'tmp' to 'arg'.

Also, change the 'err' variable to the correct type.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: NIan Abbott <abbotti@mev.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/das16m1.c

@@ -182,7 +182,8 @@ static int das16m1_cmd_test(struct comedi_device *dev,
 			    struct comedi_subdevice *s, struct comedi_cmd *cmd)
 {
 	struct das16m1_private_struct *devpriv = dev->private;
-	unsigned int err = 0, tmp;
+	int err = 0;
+	unsigned int arg;
 
 	/* Step 1 : check if triggers are trivially valid */
 
@@ -231,14 +232,12 @@ static int das16m1_cmd_test(struct comedi_device *dev,
 	/* step 4: fix up arguments */
 
 	if (cmd->convert_src == TRIG_TIMER) {
-		tmp = cmd->convert_arg;
-		/* calculate counter values that give desired timing */
+		arg = cmd->convert_arg;
 		i8253_cascade_ns_to_timer(I8254_OSC_BASE_10MHZ,
 					  &devpriv->divisor1,
 					  &devpriv->divisor2,
-					  &cmd->convert_arg, cmd->flags);
-		if (tmp != cmd->convert_arg)
-			err++;
+					  &arg, cmd->flags);
+		err |= cfc_check_trigger_arg_is(&cmd->convert_arg, arg);
 	}
 
 	if (err)