From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752936Ab0KPPaX (ORCPT ); Tue, 16 Nov 2010 10:30:23 -0500 Received: from webbox687.server-home.net ([195.149.74.151]:55526 "EHLO webbox687.server-home.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751970Ab0KPPaW (ORCPT ); Tue, 16 Nov 2010 10:30:22 -0500 From: Alexander Stein To: linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] Documentation about RS485 serial communications Date: Tue, 16 Nov 2010 16:28:13 +0100 User-Agent: KMail/1.13.5 (Linux/2.6.34-gentoo-r12; KDE/4.4.5; x86_64; ; ) Cc: Pavel Machek , Claudio Scordino , Grant Edwards , Greg KH , Nicolas Ferre , linux-kernel@vger.kernel.org, Alan Cox , linux-serial@vger.kernel.org References: <20100408111310.524f7354@lxorguk.ukuu.org.uk> <4CDBC3EC.6020707@evidence.eu.com> <20101116143016.GB6527@ucw.cz> In-Reply-To: <20101116143016.GB6527@ucw.cz> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201011161630.19107.alexander.stein@systec-electronic.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tuesday 16 November 2010, 15:30:16 Pavel Machek wrote: > > Documentation about RS485 serial communications > > I have seen hardware (kontron pmc-6l) that was capable of switching > between RS232, RS485 and one other standard by software. Maybe you mean RS422 here. > Is such hw common? If so, should we have standard interface? Especially in industrial system, you may have RS485 or RS422 additionally to RS232. This also often means switching some GPIO to change the external signal levels. Any the drivers must also be capable of turning on and off the transmitter. Best regards, Alexander