Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753947AbbEUIvA (ORCPT ); Thu, 21 May 2015 04:51:00 -0400 Received: from mail-ig0-f170.google.com ([209.85.213.170]:38289 "EHLO mail-ig0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751569AbbEUIu4 convert rfc822-to-8bit (ORCPT ); Thu, 21 May 2015 04:50:56 -0400 MIME-Version: 1.0 In-Reply-To: References: <20150515195541.GL11598@ld-irv-0074> <20150518104501.GD3551@leverpostej> <20150518183442.GR11598@ld-irv-0074> <20150519013415.GV11598@ld-irv-0074> <20150520213546.GN11598@ld-irv-0074> <20150521072515.GC11112@norris-Latitude-E6410> <20150521081526.GG11112@norris-Latitude-E6410> Date: Thu, 21 May 2015 10:50:55 +0200 Message-ID: Subject: Re: [PATCH] Documentation: dt: mtd: replace "nor-jedec" binding with "jedec,spi-nor" From: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= To: Geert Uytterhoeven Cc: Brian Norris , "linux-mtd@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Stephen Warren , Marek Vasut , linux-spi Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4380 Lines: 104 On 21 May 2015 at 10:39, Geert Uytterhoeven wrote: > Hi Rafal, Brian, > > On Thu, May 21, 2015 at 10:25 AM, Rafał Miłecki wrote: >> On 21 May 2015 at 10:15, Brian Norris wrote: >>> On Thu, May 21, 2015 at 10:01:05AM +0200, Rafał Miłecki wrote: >>>> On 21 May 2015 at 09:25, Brian Norris wrote: >>>> >> > For platform devices, you might as well just use the name of the driver, >>>> >> > which is 'm25p80'. Isn't that how most platform devices are matched with >>>> >> > drivers? >>>> >> >>>> >> Yes and I think it's ugly because it keeps causing the warning about >>>> >> read flash model not matching specified one (m25p80). >>>> > >>>> > Sure, I agree. >>>> > >>>> >> Are you >>>> >> seriously not going to allow platform stuff *clearly* request flash >>>> >> model detection (JEDEC RDID OP)? Just because they don't use DT? >>>> > >>>> > No, this isn't about "allowing" anything. It's just that my primary >>>> > concern was to get the DT binding straightened out properly. Linus' >>>> > current tree now has the proper binding, but the m25p80.c code doesn't >>>> > quite bind properly. It will work if "jedec,spi-nor" is the first >>>> > entry in the compatible property (and so it becomes the 'modalias', but >>>> > not second, third, etc. So my patch fixes that properly. >>>> > >>>> > Now, the secondary concern is that you want platform devices to specify >>>> > something generic, and that doesn't yield a "found X, expected Y" >>>> > message. I'm perfectly fine with fixing that too, if you have a patch >>>> > for it. What do you propose? >>>> >>>> Maybe I wasn't clear enough. I was going to start using struct >>>> flash_platform_data with >>>> .type = "spi-nor", >>>> but your proposed patch removes support for such name. >>> >>> Ah, OK. So that's the part I was overlooking. >>> >>>> While I like matching DT *clearly* against the whole "jedec,spi-nor" >>>> string (really, I'm all for it), I'm confused what I should use for >>>> platform stuff now. I don't have any proposal as my initial plan was >>>> exactly to use this "spi-nor". >>>> I guess I don't want to re-add support for "spi-nor" (as you just >>>> proposed to remove it), >>> >>> I wasn't really trying to remove "spi-nor", that was mostly a side >>> effect. >> >> OK, I think we understand each other now :) >> >>>> so I think I have to bounce the question: what >>>> alternative do you propose? >>> >>> I think your comments suggest that I shouldn't be removing "spi-nor" >>> from m25p_ids[] nor from this block: >>> >>> if (data && data->type) >>> flash_name = data->type; >>> else if (!strcmp(spi->modalias, "spi-nor")) >>> flash_name = NULL; /* auto-detect */ >>> else >>> flash_name = spi->modalias; >>> >>> So it stays in both m25p_ids[] and .of_match_table. >>> >>> I suppose that can work. It then allows people to do weird stuff like: >>> >>> compatible = "idontknowwhatimdoing,spi-nor"; >>> >>> in their device tree. But other than that, there's not much downside I don't >>> think. >> >> It sounds like a reasonable solution. I guess there isn't a perfect >> one. Even if we decide to go for sth like "jedec-spi-nor", there >> always will be a chance of someone using >> compatible = "idontknowwhatimdoing,jedec-spi-nor"; >> So if you rework your patch to leave "spi-nor" support in m25p_ids and >> conditions block, it should be OK. > > Typically platform devices just use the driver's name. Hence IMHO there's > no need to add a shiny new spi-nor device name. > > So what's wrong with using "m25p80", and treating that as auto-detect iff > !spi->dev.of_node? Treating "m25p80" as auto-detect triggering string won't allow platform to *force* "m25p80" flash type if there ever appears to be needed. Maybe it's unlikely, but it still sounds like a bit bad design for me. > Non-autodetect platform_devices use flash_platform_data.type anyway, > and thus fall under the first "if" clause above, don't they? They do, but I don't see the point. -- Rafał -- 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/