So IMHO there are two cases 1. The configuration is fixed in the hardware - in which case we should automatically set it in kernel, or from device tree. 2. The configuration is soft - in which case you need an ioctl you can use on the port to change it - irrespective of whether sysfs also handles it. For simple permissions reasons and also to avoid races you need that ioctl. We intentionally have lots of spare space left to extend the RS485 ioctl, and we have termiox which contains even more room and historically in other Unixen dealt with all sorts of weird and wonderful parameters used on stuff like synchronous ports. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html