From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932449AbbHXHTd (ORCPT ); Mon, 24 Aug 2015 03:19:33 -0400 Received: from lists.s-osg.org ([54.187.51.154]:59386 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932424AbbHXHTb (ORCPT ); Mon, 24 Aug 2015 03:19:31 -0400 Subject: Re: [PATCH 13/18] iio: adc: mcp320x: Set struct spi_driver .of_match_table To: Rob Herring , Jonathan Cameron References: <1440054451-1223-1-git-send-email-javier@osg.samsung.com> <1440054451-1223-14-git-send-email-javier@osg.samsung.com> <20150820200912.GA2866@deathstar> <55D64E80.4050502@osg.samsung.com> <20150820222906.GB28249@deathstar> <55D65937.6070909@osg.samsung.com> <55D8B605.4040302@kernel.org> Cc: Michael Welling , "linux-kernel@vger.kernel.org" , Andrea Galbusera , "linux-iio@vger.kernel.org" , Peter Meerwald , Lars-Peter Clausen , Manfred Schlaegl , =?UTF-8?Q?S=c3=b8ren_Andersen?= , Hartmut Knaack , "devicetree@vger.kernel.org" From: Javier Martinez Canillas Message-ID: <55DAC57C.9020502@osg.samsung.com> Date: Mon, 24 Aug 2015 09:19:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Rob and Jonathan, On 08/24/2015 12:10 AM, Rob Herring wrote: > On Sat, Aug 22, 2015 at 12:48 PM, Jonathan Cameron wrote: >> On 20/08/15 23:48, Javier Martinez Canillas wrote: >>> Hello Michael, >>> >>> On 08/21/2015 12:29 AM, Michael Welling wrote: >>>> On Fri, Aug 21, 2015 at 12:02:40AM +0200, Javier Martinez Canillas wrote: >>>>> Hello Michael, >>>>> >>>>> On 08/20/2015 10:09 PM, Michael Welling wrote: >>>>>> On Thu, Aug 20, 2015 at 09:07:26AM +0200, Javier Martinez Canillas wrote: >>>>>>> The driver has an OF id table but the .of_match_table is not set so >>>>>>> the SPI core can't do an OF style match and the table was unused. >>>>>>> >>>>>> >>>>>> Is an OF style match necessary? >>>>>> >>>>> >>>>> Did you read the cover letter [0] on which I explain why is needed to >>>>> avoid breaking module autoloading in the future? Once the SPI core is >>>>> changed by RFC patch 18/18? (you were cc'ed in the cover letter BTW). >>>> >>>> Well I have read it now. :) >>>> >>> >>> Great :) >>> >>>>> >>>>>> I have been using devicetree and it matches based on the .id_table. >>>>>> >>>>> >>>>> Yes it fallbacks to the .id_table or the driver name but the correct >>>>> thing to do for devices registered by OF, is to match using the >>>>> compatible string. >>>>> >>>>>> Couldn't we just remove the mcp320x_dt_ids table instead? >>>>>> >>>>> >>>>> No, that is the wrong thing to do IMHO since the compatible string >>>>> contains both vendor and device name whle the .id_table only contains >>>>> a device name. >>>>> >>>>> So it makes sense to match using the compatible string and also report >>>>> the OF modalias information to user-space. >>>>> >>>>> Otherwise what's the point of the vendor in the compatible string for >>>>> SPI devices? You can just use "bar" instead of "foo,bar" as a string. >>>>> >>>> >>>> Well then shouldn't the patch include adding the vendor to the compatible >>>> string? >>>> >>> >>> Well, I was talking in general. You are right that this specific driver does >>> not have a vendor prefix for the compatible strings. This is incorrect >>> according to the ePAPR document [0]. >>> >>> However, these compatible strings are already documented as a DT binding doc >>> in Documentation/devicetree/bindings/iio/adc/mcp320x.txt so I don't know >>> what is the correct thing to do in this situation. >> Take the view the old version is wrong but needs to be supported and add also >> the corrected strings + document them. >> >> cc'd The device tree list for any more comments on this. > > Agreed. Document both and mark the old one deprecated. > Thanks a lot for your comments. I'll do that as a follow up then. > Rob > Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America