From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCHv3 0/3] OMAP UART: Adding support for omap-serial driver. Date: Wed, 25 Nov 2009 10:05:12 -0800 Message-ID: <87pr76fpk7.fsf@deeprootsystems.com> References: <35552.192.168.10.88.1256713953.squirrel@dbdmail.itg.ti.com> <44977.192.168.10.88.1258095220.squirrel@dbdmail.itg.ti.com> <20091123170544.GA10313@lixom.net> <20091124172139.GA22967@lixom.net> <4B0CD762.70707@lixom.net> <20091125174044.GD4348@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-px0-f180.google.com ([209.85.216.180]:55554 "EHLO mail-px0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932179AbZKYSFI (ORCPT ); Wed, 25 Nov 2009 13:05:08 -0500 Received: by pxi10 with SMTP id 10so5937872pxi.33 for ; Wed, 25 Nov 2009 10:05:14 -0800 (PST) In-Reply-To: <20091125174044.GD4348@atomide.com> (Tony Lindgren's message of "Wed\, 25 Nov 2009 09\:40\:45 -0800") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tony Lindgren Cc: Olof Johansson , "G, Manjunath Kondaiah" , "Shilimkar, Santosh" , Govindraj , "linux-omap@vger.kernel.org" , "Pandita, Vikram" , "Raja, Govindraj" Tony Lindgren writes: > * Olof Johansson [091124 23:05]: >> G, Manjunath Kondaiah wrote: >> >>>You should allow both of them to be enabled at the same time, so the >> >>>same >> >>>kernel can for example be booted on a ZOOM2 with debug board >> >>>attached >> >>>(8250 on GPMC), or on a beagle/overo board. >> >>> >> >>>Making them exclusive would be a step backwards. >> >>More so, selecting both config option really shouldn't break the >> >>build. If one expect a build break because only one of the >> >>options can be enabled then clearly the dependency should be >> >>used so that user can select only one option at a time. >> > >> >Ack. There should be dependency in Kconfig so that user can select >> >either 8250 console(through Quad-uart for zoom2/zoom3) or OMAP-serial >> >Console(through OMAP UART's). >> >> No. The drivers MUST handle co-existing. You can have a bunch of >> drivers configured to be _potential_ consoles, which one will end up >> being used depends on, among other things, the bootargs. But it >> should be allowed to configure both 8250 and omap-serial at the same >> time. > > Exactly. Even the same board must be capable of using 8250 and > omap-serial. That's why it must be called ttyO instead of ttyS. I completely agree with the need for these drivers to co-exist and for a given board to use both drivers. For example, Zoom2 would want to use omap-serial for the on-chip UARTs, and 8250 for the external UART used for the console. In my review I complained about using ttyO instead of ttyS, but now I see more clearly the reason for that. Kevin