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++;
-       }
 #define MAX_SPEED      10000   /* in nanoseconds */
 #define MIN_SPEED      1000000000      /* in nanoseconds */
 
        if (cmd->scan_begin_src == TRIG_TIMER) {
-               if (cmd->scan_begin_arg < MAX_SPEED) {
-                       cmd->scan_begin_arg = MAX_SPEED;
-                       err++;
-               }
-               if (cmd->scan_begin_arg > MIN_SPEED) {
-                       cmd->scan_begin_arg = MIN_SPEED;
-                       err++;
-               }
+               err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
+                                                MAX_SPEED);
+               err |= cfc_check_trigger_arg_max(&cmd->scan_begin_arg,
+                                                MIN_SPEED);
        } else {
                /* external trigger */
                /* should be level/edge, hi/lo specification here */
                /* should specify multiple external triggers */
-               if (cmd->scan_begin_arg > 9) {
-                       cmd->scan_begin_arg = 9;
-                       err++;
-               }
+               err |= cfc_check_trigger_arg_max(&cmd->scan_begin_arg, 9);
        }
        if (cmd->convert_src == TRIG_TIMER) {
-               if (cmd->convert_arg < MAX_SPEED) {
-                       cmd->convert_arg = MAX_SPEED;
-                       err++;
-               }
-               if (cmd->convert_arg > MIN_SPEED) {
-                       cmd->convert_arg = MIN_SPEED;
-                       err++;
-               }
+               err |= cfc_check_trigger_arg_min(&cmd->convert_arg,
+                                                MAX_SPEED);
+               err |= cfc_check_trigger_arg_max(&cmd->convert_arg,
+                                                MIN_SPEED);
        } else {
                /* external trigger */
                /* see above */
-               if (cmd->convert_arg > 9) {
-                       cmd->convert_arg = 9;
-                       err++;
-               }
+               err |= cfc_check_trigger_arg_max(&cmd->convert_arg, 9);
        }
 
-       if (cmd->scan_end_arg != cmd->chanlist_len) {
-               cmd->scan_end_arg = cmd->chanlist_len;
-               err++;
-       }
-       if (cmd->stop_src == TRIG_COUNT) {
-               if (cmd->stop_arg > 0x00ffffff) {
-                       cmd->stop_arg = 0x00ffffff;
-                       err++;
-               }
-       } else {
-               /* TRIG_NONE */
-               if (cmd->stop_arg != 0) {
-                       cmd->stop_arg = 0;
-                       err++;
-               }
-       }
+       err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
+
+       if (cmd->stop_src == TRIG_COUNT)
+               err |= cfc_check_trigger_arg_max(&cmd->stop_arg, 0x00ffffff);
+       else    /* TRIG_NONE */
+               err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
        if (err)
                return 3;