From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752678AbdBAVPH (ORCPT ); Wed, 1 Feb 2017 16:15:07 -0500 Received: from ec2-52-27-115-49.us-west-2.compute.amazonaws.com ([52.27.115.49]:44946 "EHLO osg.samsung.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752589AbdBAVPD (ORCPT ); Wed, 1 Feb 2017 16:15:03 -0500 Subject: Re: [PATCH v9 6/8] drivers:input:ads7846(+tsc2046): fix spi module table To: "H. Nikolaus Schaller" , Dmitry Torokhov References: <20170128193558.GC38136@dtor-ws> <20170129180108.GA10743@dtor-ws> From: Javier Martinez Canillas Cc: Mark Rutland , Michel Verlaan , Nick Dyer , Tony Lindgren , LKML , Benjamin Tissoires , linux-omap , Russell King , Igor Grinberg , Hans Verkuil , linux-input@vger.kernel.org, devicetree , Arnd Bergmann , Eric Engestrom , Hans de Goede , Rob Herring , =?UTF-8?Q?Mika_Penttil=c3=a4?= , Mauro Carvalho Chehab , Petr Cvek , Siebren Vroegindeweij , Sebastian Reichel , linux-iio@vger.kernel.org, "Andrew F. Davis" , Mark Brown , =?UTF-8?Q?Beno=c3=aet_Cousson?= , kernel@pyra-handheld.com, Michael Welling , Jonathan Cameron , Alexander Stein , Discussions about the Letux Kernel Message-ID: Date: Wed, 1 Feb 2017 18:14:39 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Nikolaus, On 02/01/2017 05:20 PM, H. Nikolaus Schaller wrote: > Hi Dmitry, Javier, > >> Am 29.01.2017 um 19:25 schrieb H. Nikolaus Schaller : >> >> Hi Dmitry, >> >>> Am 29.01.2017 um 19:01 schrieb Dmitry Torokhov : >>> >>> On Sun, Jan 29, 2017 at 09:39:39AM +0100, H. Nikolaus Schaller wrote: >>>> Hi Dmitry, >>>> >>>>> Am 28.01.2017 um 20:35 schrieb Dmitry Torokhov : >>>>> >>>>> On Wed, Dec 28, 2016 at 03:53:21PM +0100, H. Nikolaus Schaller wrote: >>>>>> Fix module table so that the driver is loaded if compiled >>>>>> as module and requested by DT. >>>>>> >>>>> >>>>> I believe I already replied to a similar patch: we alreadyhave necessary >>>>> aliases in this driver, we need to fix module loading to use it. >>>> >>>> Yes, you did comment on [PATCH v6 7/8] (19 Nov 2016): >>>> >>>>>> We really need to fix it between spi/i23c core and module utils instead >>>>>> of keeping adding duplicate IDs all over drivers. We already have OF >>>>>> module device table containing the same data, we should be able to use >>>>>> it. >>>> >>>> And Javier Martinez Canillas replied (23 Nov 2016): >>>> >>>>> Agreed, unfortunately until the I2C and SPI core are changed to properly >>>>> report OF modaliases, we will have to keep adding these duplicated IDs. >>>>> >>>>> And changing the I2C and SPI core isn't trivial since it could break a >>>>> lot of drivers that rely on a platform modalias being reported (i.e: no >>>>> OF device IDs present in the drivers even when are registered via DT). >>>> >>>> Therefore I didn't see a need to change it. >>> >>> I agree that changing I2C and SPI core is not trivial, however this is >>> no reason for piling up workarounds in all drivers. Are you seriously >>> advocating going though *every* driver and copying OF data into I2C/SPI >>> instead of doing the right thing and fixing the root of the issue? >> >> If you prefer to have this done (and I agree it would be a tiny improvement), >> please do it for us all. But please after merging this workaround. > > Have we been lucky to find someone who is able and willing to work on this? > As said, changing the core is trivial. A RFC patch is [0]. The problem is how to make sure that this change won't cause regressions in existing drivers. There was particularly tricky for the spi-nor driver, it doesn't help that a lot of DT are using undocumented compatible strings (sometimes with no vendor prefix). You can see the discussion here [1]. In the same thread Mark Brown said that it wasn't that bad to have the information in the OF device ID table duplicated in a SPI device table. Certainly isn't the best approach but IMHO is better than the module not loading. https://patchwork.kernel.org/patch/7041141/ https://patchwork.ozlabs.org/patch/545125/ > If not, I'd recommend to stay with the current level of optimality. > > BR and thanks, > Nikolaus > Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America