From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: =?UTF-8?B?562U5aSNOiBbUEFUQ0ggdjMgMi8yXSBpMmM6IGlteDogQWRkIFY=?= =?UTF-8?B?eWJyaWQgVkY2MTAgSTJDIGNvbnRyb2xsZXIgc3VwcG9ydA==?= Date: Tue, 13 Aug 2013 09:48:40 -0600 Message-ID: <520A5558.708@wwwdotorg.org> References: <1375418648-22760-1-git-send-email-b35083@freescale.com> <1375418648-22760-2-git-send-email-b35083@freescale.com> <20130810140827.GC18085@e106331-lin.cambridge.arm.com> <20130812164354.GF27165@e106331-lin.cambridge.arm.com> <52096E77.4040003@wwwdotorg.org> <20130813074620.GR26614@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130813074620.GR26614-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org" Cc: Mark Rutland , Lu Jingchang-B35083 , "wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org" , Estevam Fabio-R49496 , Li Xiaochun-B41219 , "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Jin Zhengxiong-R64188 , "shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , pawel.moll-5wv7dgnIgG8@public.gmane.org, ian.campbell-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org, grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, tomasz.figa-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org, galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org List-Id: linux-i2c@vger.kernel.org On 08/13/2013 01:46 AM, s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org wrote: > On Mon, Aug 12, 2013 at 05:23:35PM -0600, Stephen Warren wrote: >> On 08/12/2013 10:43 AM, Mark Rutland wrote: >>>> The binding string for i2c-imx driver in Documentation/devicetree/bindings/i2c/i2c-imx.txt use a wildcard format >>>> of "- compatible : Should be "fsl,-i2c" " for device using this driver. Neither fsl,imx1-i2c nor fsl,imx21-i2c >>>> is described in the binding document. So I just leave the vf610 i2c compatible with this. >>> >>> I'm not a big fan on wildcards in bindings, as it leaves people free to >>> put anything in and claim it's a documented binding, and makes it far >>> harder for an os to actually implement drivers for said binding, as >>> there's no canonical reference for the set of valid variations. >>> >>> Obviously there is some precedent, but I'm not sure it's something we >>> want to stick with, and we can prevent it my updating the documentation >>> now. >>> >>> Does anyone else have an opinion? >> >> I suppose technically we should list out every exact string in the >> binding, but it's a little annoying to have to update the binding doc >> every time a new chip comes out (and I expect that'll happen more and >> more!) just to add a new compatible value since all the differences are >> known internally to the driver and don't impact the binding... > > We would only have to update the the docs when an incompatible SoC comes > out. For this particular driver this would be all marked with a star: > > * i.MX1 > * i.MX21 > i.MX25 > i.MX27 > i.MX31 > i.MX35 > i.MX51 > i.MX53 > i.MX6 > * Vybrid > > That's not too many updates to the binding docs since 2001. > (The SPI core changed with nearly every SoC version though) So, the SPI core changed its HW implementation, or changed its SW-visible interface? If the latter, then you need a separate compatible value for each, which was my point.