From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 5.mo2.mail-out.ovh.net ([87.98.181.248]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cPROD-0000h5-Ny for linux-mtd@lists.infradead.org; Fri, 06 Jan 2017 10:04:52 +0000 Received: from player728.ha.ovh.net (b7.ovh.net [213.186.33.57]) by mo2.mail-out.ovh.net (Postfix) with ESMTP id AAE6516AE8 for ; Fri, 6 Jan 2017 11:04:26 +0100 (CET) Subject: Re: [PATCH v4 1/4] mtd: spi-nor: add memory controllers for the Aspeed AST2500 SoC To: Boris Brezillon References: <1481557252-13656-1-git-send-email-clg@kaod.org> <1481557252-13656-2-git-send-email-clg@kaod.org> <5566c62d-cc72-f207-e1dd-5a59e6947c24@wedev4u.fr> <2bec1e91-a196-b894-fb66-590b8f4f35c3@atmel.com> <645db8c4-7f3c-f8bf-ddd9-3f513ce2ed14@kaod.org> <4c5cf674-06f9-ad6b-05bf-a1d39aaa7ed5@atmel.com> <20170104185005.7fcafd2d@bbrezillon> <4c0b4498-12c7-303d-c8f8-4f27a02d6c12@kaod.org> <20170106094930.0f579dca@bbrezillon> Cc: Cyrille Pitchen , Cyrille Pitchen , linux-mtd@lists.infradead.org, Mark Rutland , devicetree@vger.kernel.org, Richard Weinberger , Marek Vasut , Rob Herring , Joel Stanley , Brian Norris , David Woodhouse From: =?UTF-8?Q?C=c3=a9dric_Le_Goater?= Message-ID: <5017c983-e619-b3db-404c-8eab45bdd1f8@kaod.org> Date: Fri, 6 Jan 2017 11:04:12 +0100 MIME-Version: 1.0 In-Reply-To: <20170106094930.0f579dca@bbrezillon> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello Boris, On 01/06/2017 09:49 AM, Boris Brezillon wrote: > Hi Cédric, > > On Thu, 5 Jan 2017 14:39:14 +0100 > Cédric Le Goater wrote: > >> Hello Cyrille, Boris >> >> On 01/04/2017 06:50 PM, Boris Brezillon wrote: >>> Cyrille, Cédric, >>> >>> On Wed, 4 Jan 2017 15:52:07 +0100 >>> Cyrille Pitchen wrote: >>> >>>>> >>>>>> Anyway, since the review is done now, on my side I won't ask you to remove >>>>>> or split the support of the 'Command' mode in a separated patch. >>>>>> I let you do as you want, if it help you to introduce some part of the >>>>>> support of this 'Command' mode now even if not completed yet, no problem on >>>>>> my side :) >>>>>> >>>>>> I was just giving you some pieces of advice for the next time if you want >>>>>> to speed up the review of another patch introducing new features. >>>>>> >>>>>> However, I will just ask you one more version handling the dummy cycles >>>>>> properly as it would help us for the global maintenance of the spi-nor >>>>>> subsystem. This is the only mandatory modification I ask you, after that I >>>>>> think it would be ok for me and since Marek has already reviewed your >>>>>> driver, it would be ready to be merged into the spi-nor tree. >>>>> >>>>> Sending a v5 which should address your comments. >>>>> >>>>> I have removed the label property and will start a new thread in the >>>>> topic. Any hints on which binding we could add this label prop ? >>>>> >>>> >>>> Here I will provide just few thoughts about this new DT property. I don't >>>> pretend this is what should be done. I still think other mtd maintainers >>>> should be involved to discuss this topic. >>>> >>>> First the DT property name "label" sounds good to me: it is consistent with >>>> "label" DT property used to name mtd partitions. However, I don't think it >>>> should be documented in jedec,spi-nor.txt but *maybe* in partition.txt as >>>> the purpose of this new DT property seems very close to the "label" >>>> property of partition nodes: let's think about some hard-disk device >>>> (/dev/sda) and its partition devices (/dev/sdaX). >> >> yes this is very similar. I first looked at introducing a name to >> an overall containing partition but the partition binding is not >> designed for that. There are constraints on the start address and >> the size which does not fit the purpose. >> >>> Hm, partition.txt may not be appropriate here. We're not documenting >>> the MTD partition binding, but the MTD device one. Maybe we should >>> create mtd.txt and put all generic MTD dev properties here. >>>> >>>> Besides, the concept of this memory label is not limited to SPI NOR but >>>> could also apply to NAND memories or any other MTD handled memories. >>> >>> Definitely. Actually I think I'll need that for the Atmel NAND >>> controller driver rework I'm currently working on, to keep mtdparts >>> parser happy even after changing the NAND device naming scheme. >>> >>>> Hence the DT property might be handled by drivers/mtd/ofpart.c instead of >>>> being handled by spi-nor.c or by each SPI NOR memory controller driver. >>> >>> Actually, that could be done at the mtdcore level in >>> mtd_set_dev_defaults() [1]. >> >> that would be perfect. >> >>>> Finally, I guess we should take time to discuss and all agree what should >>>> be done precisely before introducing a new DT property because one general >>>> rule with DTB files is that users should be able to update their kernel >>>> image (zImage, uImage, ...) without changing their DTB: device trees should >>>> be backward compatible. Hence if we make a wrong choice today, we are >>>> likely to have to live with it and keep supporting that bad choice. >>> >>> Rob already acked the patch, so, if all MTD maintainers agree that this >>> new property is acceptable, we should be fine ;-). >> >> yes but we would need to move the binding property to another file. >> What I sent applied to "jedec,spi-nor" and we want to generalize the >> property to other devices. > > We could create an new file under > Documentation/devicetree/bindings/mtd/, or we could rename > partition.txt into something else (generic.txt or common.txt) and > document more than the partition binding. OK. I guess that creating a new file for a single property is a little overkill or do we expect more common properties at the device level ? In that case, may be we could keep the partition.txt file and add a common.txt file. If not, common.txt seems to be a good name. Waiting a little for others to chime in. > Can you take care of that (in a separate patch series of course)? sure, and will you send : http://code.bulix.org/p019ah-107877 in a separate patch ? Thanks, C.