Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755529AbbEUIZR (ORCPT ); Thu, 21 May 2015 04:25:17 -0400 Received: from mail-ig0-f177.google.com ([209.85.213.177]:32967 "EHLO mail-ig0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751385AbbEUIZL convert rfc822-to-8bit (ORCPT ); Thu, 21 May 2015 04:25:11 -0400 MIME-Version: 1.0 In-Reply-To: <20150521081526.GG11112@norris-Latitude-E6410> 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 10:25:11 +0200 Message-ID: Subject: Re: [PATCH] Documentation: dt: mtd: replace "nor-jedec" binding with "jedec,spi-nor" From: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= To: Brian Norris Cc: Geert Uytterhoeven , "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: 4704 Lines: 109 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: >> > (trim CC a bit, as this is no longer a DT binding question) >> > >> > On Thu, May 21, 2015 at 09:12:25AM +0200, Rafał Miłecki wrote: >> >> On 20 May 2015 at 23:35, Brian Norris wrote: >> >> > On Tue, May 19, 2015 at 09:27:50AM +0200, Rafał Miłecki wrote: >> >> >> On 19 May 2015 at 03:34, Brian Norris wrote: >> >> >> > So how about the following patch? It seems like we'll need to be able to >> >> >> > ignore useless 'modalias' values in cases like this: >> >> >> > >> >> >> > // modalias = "shinynewdevice" >> >> >> > compatible = "myvendor,shinynewdevice", "jedec,spi-nor"; >> >> >> > >> >> >> > and also if somebody leaves off the entire shinynewdevice string: >> >> >> > >> >> >> > // modalias = "spi-nor" >> >> >> > compatible = "jedec,spi-nor"; >> >> >> > >> >> >> > So we rework the spi-nor library to not reject "bad" names, and just >> >> >> > fall back to autodetection, and we add the .of_match_table to properly >> >> >> > catch all "jedec,spi-nor". >> >> >> >> >> >> That's nice but what about platforms using platform data instead of >> >> >> DT? I would like to use some kind of "spi-nor" (with some prefix >> >> >> *maybe*) for them too. >> >> > >> >> > 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. -- 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/