Re: [PATCH 1/5] tty: add port flag to suppress ready signalling on open

From: Mychaela Falconia
Date: Mon Nov 30 2020 - 18:36:53 EST


> Add a 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.
>
> This can be use to prevent undesirable side-effects on open for
> applications where the DTR and RTS lines are used for non-standard
> purposes such as generating power-on and reset pulses.
>
> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>

Reviewed-by: Mychaela N. Falconia <falcon@xxxxxxxxxxxxxxx>