Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964882AbaGCPoe (ORCPT ); Thu, 3 Jul 2014 11:44:34 -0400 Received: from mail.kernel.org ([198.145.19.201]:39609 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932231AbaGCPoc (ORCPT ); Thu, 3 Jul 2014 11:44:32 -0400 Date: Thu, 3 Jul 2014 17:44:26 +0200 From: Sebastian Reichel To: Felipe Balbi Cc: Robert Nelson , Tony Lindgren , Aaro Koskinen , Sebastian Andrzej Siewior , linux kernel , linux-serial@vger.kernel.org, Linux OMAP Mailing List , Linux ARM Kernel Mailing List Subject: Re: [RFC PATCH] tty: serial: Add 8250-core based omap driver Message-ID: <20140703154425.GC23309@earth.universe> References: <1404316809-20637-1-git-send-email-bigeasy@linutronix.de> <20140702160932.GF5541@saruman.home> <20140702190944.GA567@drone.musicnaut.iki.fi> <20140703073411.GX28884@atomide.com> <20140703132509.GA5814@saruman.home> <20140703140736.GF5814@saruman.home> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="69pVuxX8awAiJ7fD" Content-Disposition: inline In-Reply-To: <20140703140736.GF5814@saruman.home> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --69pVuxX8awAiJ7fD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Thu, Jul 03, 2014 at 09:07:36AM -0500, Felipe Balbi wrote: > On Thu, Jul 03, 2014 at 08:34:44AM -0500, Robert Nelson wrote: > > On Thu, Jul 3, 2014 at 8:25 AM, Felipe Balbi wrote: > > > On Thu, Jul 03, 2014 at 12:34:11AM -0700, Tony Lindgren wrote: > > >> * Robert Nelson [140702 12:27]: > > >> > On Wed, Jul 2, 2014 at 2:09 PM, Aaro Koskinen wrote: > > >> > > Hi, > > >> > > > > >> > > On Wed, Jul 02, 2014 at 11:09:32AM -0500, Felipe Balbi wrote: > > >> > >> > It has been only tested as console UART. > > >> > >> > The tty name is ttyS based instead of ttyO. How big is the pa= in here, > > >> > >> > what could be the easiest way to provide compatibility? > > >> > >> > > >> > >> have been considering that myself for months. You could pass an= optional > > >> > >> argument to serial8250_register_8250_port() but that only solve= s part of > > >> > >> the problem :-( > > >> > > >> Some kind of compability layer sure would be nice. > > >> > > >> > > When ttyS -> ttyO change was done on OMAP, compatibility was not= an issue. > > >> > > Why should we care about it now? > > >> > > > >> > It would be a good opportunity to force everyone to update their b= ootloader. ;) > > >> > > > >> > Besides the BeagleBoard forum is quiet now, no one is complaining > > >> > about that old (ttyS -> ttyO) transition anymore.. > > >> > > >> How about a Kconfig option to provide ttyO by default? The not even > > >> do that if kernel has cmdline option nottyomap. > > > > > > what about single zImage ? I don't want to use ttyO on my > > > Allwinner/Exynos/Snapdragon/whatever SoC just because OMAP is in the > > > same image ;-) > >=20 > > What if we just kept it simple, leave the ttyO driver enabled and add > > a warning (pr_info) that it's deprecated. It's not like it's broken, > > it just won't get later features or devices support added. >=20 > Fine by me, I'd switch to 8250 as soon as it's merged though :-) would > be nice to get an example DTS change just so I can start testing on the > boards I have around. DT is supposed to contain information about the hardware, so it should stay the same? I think there is no non-hackish way to decide at runtime which driver should be loaded. One possible solution is: * Keep both drivers for a couple of kernel releases * Add the deprecation warning to the older one * Add a conflict between both drivers in Kconfig Thus its decided at build-time, which driver should be used. This would keep existing .config files working for a couple of releases. -- Sebastian --69pVuxX8awAiJ7fD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCgAGBQJTtXpZAAoJENju1/PIO/qappYP/R9wu/GOonPfQo6uZ7gohmIW opHVKIl8XNOPMQ6PGjV849jl8INwcnSFSfIf9ToseGDR3mlarPSORmNb80NddTBL WDjHjiajxQHfOn3gvFt/g4T/MWL7TvaubcdjGrrPYHqFbmSf8+Du4jil/74Le4Wc D3gK37AivYXv6E81dAlLRmxbusKkLvGJ8oa+t0vV+tM5ScdZyUzoZ512oYLqcC/J B8hypu3Ug12nA7qREpVAysdMf0tQmAn06+cwUQkQfWjMgLXwE3U9bu3kJC5BpgZe 4iEyLYj6291PhDasQJp6akml5aKfZcaqmuhjqu2/fv9guYzb4Mc9Vl4hFJZONoBR KcyESrGFqDFxULTTbDhrpW6SlYSg1lAAD0wCrWHld6Lsnz7DNqjIc6TDlmkN+Pqg X/ZvcsHXC6MyG1VcXSruGoveafqPhODMVr4Lx4HSAh2LCUDaN/U7pHDuMlo1wBpQ sFhO/sWR4mcfk4WNnxaMhSmrU8ShsF6SMCAYhcCgXM8kg/g8FuD9qQ5rg/Hs9A0l kmT4bJZ8Etqx4hfLxq6LIvmeN1ZLILBdQ7VkqkoenpwIkAOSxDo0vAIAHu8kC65S I9fbZWn7c0R8UDuvbJlInSnPq4lckE2t+Nr7wHFh6K2/31lmqAIr6evNn9+GWfQC 7kKld0rXUe2YVhZwhCBV =cZXg -----END PGP SIGNATURE----- --69pVuxX8awAiJ7fD-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/