> + /* > + * Check value: baud_base has to be more than 9600 > + * and uartclock = baud_base * 16 . > + */ > + if (val >= 153600) > + state->uart_port->uartclk = val; > + > + mutex_unlock(&state->port.mutex); > + > + return count; This breaks if for example the port is in use. Fixing that looks pretty horrible as you need a valid tty pointer to stop and restart the pot. It's also not calling the verfy method of the port as is expected. At minimum I think you need to be able to do the same work uart_get_info/uart_set_info perform and with the same checks on ->verify etc. I'm not 100% sure the drvdata on the tty_dev is clear to use. It does seem to be in all the drivers I looked at. I'd rather however it pointed to the tty_port that each tty device has (or very soon will be required to have). You can still find the uart_foo structs from that but it means we can do the dev_set_drvdata() in a consistent manner for all tty devices in the kernel. That in turn means we can make some of the sysfs valid the same way. I want to have think about the setting side of it. Can you submit a revised version that just allows the user to read the value this way but does the drvdata setting etc and sysfs node create/delete. I'll merge that and we can throw it over the parapet and see if anything explodes. To make the setting part work properly I think I need to sort out uart_get_info/set_info so the core part of it can be called with kernel space structures and the caller handling locks. 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