if (err)
                return 2;
 
-       /* step 3: make sure arguments are trivially compatible */
+       /* Step 3: check if arguments are trivially valid */
+
+       err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 
-       if (cmd->start_arg != 0) {
-               cmd->start_arg = 0;
-               err++;
-       }
        if (cmd->scan_begin_src == TRIG_FOLLOW) {
                /* internal trigger */
-               if (cmd->scan_begin_arg != 0) {
-                       cmd->scan_begin_arg = 0;
-                       err++;
-               }
+               err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
        } else {
 #if 0
                /* external trigger */
                /* should be level/edge, hi/lo specification here */
-               if (cmd->scan_begin_arg != 0) {
-                       cmd->scan_begin_arg = 0;
-                       err++;
-               }
+               err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 #endif
        }
 
-       if (cmd->convert_arg < 10000) {
-               cmd->convert_arg = 10000;
-               err++;
-       }
+       err |= cfc_check_trigger_arg_min(&cmd->convert_arg, 10000);
 #if 0
-       if (cmd->convert_arg > SLOWEST_TIMER) {
-               cmd->convert_arg = SLOWEST_TIMER;
-               err++;
-       }
+       err |= cfc_check_trigger_arg_max(&cmd->convert_arg, SLOWEST_TIMER);
 #endif
-       if (cmd->scan_end_arg != cmd->chanlist_len) {
-               cmd->scan_end_arg = cmd->chanlist_len;
-               err++;
-       }
+
+       err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
+
        if (cmd->stop_src == TRIG_COUNT) {
                /* any count is allowed */
-       } else {
-               /* TRIG_NONE */
-               if (cmd->stop_arg != 0) {
-                       cmd->stop_arg = 0;
-                       err++;
-               }
+       } else {        /* TRIG_NONE */
+               err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
        }
 
        if (err)