From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Quadros Subject: Re: [RFC PATCH 00/16] OMAP: GPMC: Restructure OMAP GPMC driver (NAND) : DT binding change proposal Date: Mon, 26 May 2014 10:33:52 +0300 Message-ID: <5382EE60.3000808@ti.com> References: <1400671264-10702-1-git-send-email-rogerq@ti.com> <20140521160818.GA1150@arch.cereza> <537DB17A.6060608@ti.com> <20140522144600.GA1785@arch.cereza> <537F03C8.3070101@ti.com> <20140523145354.GE2321@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140523145354.GE2321@atomide.com> Sender: linux-kernel-owner@vger.kernel.org To: Tony Lindgren Cc: Ezequiel Garcia , Javier Martinez Canillas , Brian Norris , "Gupta, Pekon" , Robert Nelson , Jingoo Han , dwmw2@infradead.org, nsekhar@ti.com, "linux-omap@vger.kernel.org" , linux-mtd@lists.infradead.org, "devicetree@vger.kernel.org" , Linux Kernel , Grant Likely , Rob Herring List-Id: devicetree@vger.kernel.org On 05/23/2014 05:53 PM, Tony Lindgren wrote: > * Roger Quadros [140523 01:17]: >> On 05/22/2014 05:46 PM, Ezequiel Garcia wrote: >>> On 22 May 01:51 PM, Javier Martinez Canillas wrote: >>>> On Thu, May 22, 2014 at 10:12 AM, Roger Quadros wrote: >>>>>> On 21 May 02:20 PM, Roger Quadros wrote: >>>>>> While I agree that the GPMC driver is a bit messy, I'm not sure it's possible >>>>>> to go through such a complete devicetree binding re-design (breaking backwards >>>>>> compatibility) now that the binding is already in production. >>>>> >>>>> Why not? especially if the existing bindings are poorly dones. Is anyone using these >>>>> bindings burning the DT into ROM and can't change it when they update the kernel? >>>>> >>>> >>>> While I do agree that your DT bindings are much better than the >>>> current ones, there is a policy that DT bindings are an external API >>>> and once are released with a kernel are set in stone and can't be >>>> changed. >>>> >>> >>> Exactly. The DT binding is considered an ABI. Thus, invariant across kernel >>> versions. Users can't be coherced into a DTB update after a kernel update. >>> >>> That said, I don't really care if you break compatilibity in this case. >>> Rather, I'm suggesting that you make sure this change is going to be accepted >>> upstream, before doing any more work. The DT maintainers are reluctant to do >>> so. >> >> Appreciate your concern. >> >> Would be really nice if you can review patches 1-12. They have nothing to do with DT changes. >> Thanks. > > I'm mostly concerned about keeping things working. I think the > only way we can keep things working is to keep support for > the old binding around in addition to the new one. That way > we can update devices one at a time. Good to hear that you are not keen on keeping the old bindings forever. I understand that we need to keep things working during the transition. I'll think of something to maintain backward compatibility while supporting the new binding. cheers, -roger