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From: "Enrico Weigelt, metux IT consult" <enrico.weigelt@gr13.net>
To: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Directly accessing serial ports from drivers w/o TTYs ?
Date: Thu, 29 Jun 2017 11:44:58 +0000	[thread overview]
Message-ID: <cf910296-8bd9-aca8-079b-149580f1ddd0@gr13.net> (raw)
In-Reply-To: <20170626155115.13617ed6@alans-desktop>

On 26.06.2017 14:51, Alan Cox wrote:

Hi,

> You can write your own driver for the physical hardware and claim it in
> your driver. Shouldn't normally be needed except for bizarre cases when a
> serial link is used for something very non tty like (eg as GPIO lines).

In my case, it's not really a serial link, but an backplane w/ FIFOs, 
which looks like a serial ports to the host (AFAIK, historically coming
from older systems which actually had various serial controllers, eg.
rs232, rs485/mvb, etc). The backplane seems to simulate the lower
layers of an mvb network.

> Otherwise all the low level tty device locking, queues and interfaces
> assume there is a tty_struct attached to it, so yes you need a tty
> struct.

I was thinking about something that looks like serdev from consumer
side, but instead directly works on struct uart_port, w/o actually
allocating a tty (and also the funny things like signals, etc).

> Why do you need to do otherwise ?

Maybe it could offer better performance ?


--mtx

  reply	other threads:[~2017-06-29 11:45 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-25 22:43 Directly accessing serial ports from drivers w/o TTYs ? Enrico Weigelt, metux IT consult
2017-06-26 14:51 ` Alan Cox
2017-06-29 11:44   ` Enrico Weigelt, metux IT consult [this message]
2017-06-30 17:23     ` Alan Cox

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