This series adds a new NORDY port flag to suppress raising the modem-control lines on open to signal DTE readiness. This can be used to implement a NORDY termios control flag to complement HUPCL, which controls lowering of the modem-control lines on final close. Initially drivers can export the flag through sysfs, which also allows control over the lines on first open. Such an interface is implemented for serial core and USB serial. The motivation for this is to allow for applications where the DTR and RTS lines are used for non-standard purposes (e.g. generating power-on and reset pulses) to open the port without undesirable side effects. The final patches enables this flag by default for such a USB serial device. Greg, are you ok we me taking this through my tree? I'm planning on some follow ups to the ftdi driver and the tty/serial changes are fairly self-contained. Johan Johan Hovold (3): tty: add port flag to suppress ready signalling on open serial: core: add sysfs attribute to suppress ready signalling on open USB: serial: add sysfs attribute to suppress ready signalling on open Mychaela N. Falconia (2): USB: serial: ftdi_sio: pass port to quirk port_probe functions USB: serial: ftdi_sio: add support for FreeCalypso DUART28C adapter Documentation/ABI/testing/sysfs-tty | 7 +++++ drivers/tty/serial/serial_core.c | 29 ++++++++++++++++++++ drivers/tty/tty_port.c | 2 +- drivers/usb/serial/bus.c | 38 ++++++++++++++++++++++++-- drivers/usb/serial/ftdi_sio.c | 42 +++++++++++++++++++++++------ drivers/usb/serial/ftdi_sio_ids.h | 1 + include/linux/tty.h | 14 ++++++++++ 7 files changed, 122 insertions(+), 11 deletions(-) -- 2.26.2