From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Hurley <peter@hurleysoftware.com>
Subject: Re: [PATCH v8 3/3] tty: 8250_omap: Use software emulated RS485
 direction control
Date: Thu, 18 Feb 2016 08:50:03 -0800
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Cc: Greg KH <gregkh@linuxfoundation.org>, Jiri Slaby <jslaby@suse.com>, Andy Shevchenko <andy.shevchenko@gmail.com>, One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>, linux-kernel <linux-kernel@vger.kernel.org>, linux-serial@vger.kernel.org
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On 02/18/2016 01:46 AM, =D0=98=D0=BB=D1=8C=D1=8F=D1=81 =D0=93=D0=B0=D1=81=
=D0=B0=D0=BD=D0=BE=D0=B2 wrote:
> 2016-02-18 10:18 GMT+03:00 =D0=98=D0=BB=D1=8C=D1=8F=D1=81 =D0=93=D0=B0=
=D1=81=D0=B0=D0=BD=D0=BE=D0=B2 <torso.nafi@gmail.com>:
>> Also, forgot to mention that if serial8250_em485_init is called not
>> upon uart startup but elsewhere (upon port register for example), an=
d
>> em485 is set, serial8250_do_startup should call
>> serial8250_em485_rts_after_send, or else RTS might be in wrong state
>> whenever the port device is opened, making it impossible to receive
>> data through RTS-controlled RS232<->RS485 hardware converters.
>=20
> Just found out that it doesn't help. Actually, it is the behavior of
> tty_open function to call tty_port_block_til_ready after startup, and
> of the latter - to set RTS via ioctl if baud is not zero - both of
> which cannot be overriden within the scope of the 8250 framework. The
> reason this works in legacy omap_serial is that my GPIO which is used
> to emulate RTS is not tied to mctrl there, so the call of
> tty_port_block_til_ready does not affect its state.
>=20
> Therefore, a check for SER_RS485_ENABLED needs to be introduced to
> tty_port_block_til_ready.

No, that's not the way.

=46irst, there's plenty of driver hooks to properly manage the RTS leve=
l
for rs485.
Second, how are you running GPIO rts with the omap8250 driver?