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Date:   Fri, 4 May 2018 09:59:04 -0400
From:   "Theodore Y. Ts'o" <tytso@mit.edu>
To:     Muni Sekhar <munisekharrms@gmail.com>
Cc:     linux-serial <linux-serial@vger.kernel.org>,
        linux-kernel@vger.kernel.org
Subject: Re: serial: custom baud rate
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On Fri, May 04, 2018 at 02:34:51PM +0530, Muni Sekhar wrote:
> > See the setserial man page:t
> >
> >         https://linux.die.net/man/8/setserial
> >
> > Not all serial devices support the spd_cust and divisor, however.  In
> > general, only devices where the kernel directly programs the
> > 8250/16450/16550 UART directly will support this feature.
> >
> So custom baud's can be set via TIOCSSERIAL IOCtl in kernel mode?

ioctl's are in general designed for use in userspace.  So are the
termios interface.

					- Ted