On Tue, Aug 13, 2013 at 09:48:40AM -0600, Stephen Warren wrote: > On 08/13/2013 01:46 AM, s.hauer@xxxxxxxxxxxxxx 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,<chip>-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. It changed the SW-visible interface. I vote for having the exact SoC revision in the binding documentation rather than wildcards or references to the list of i.MX SoCs. Otherwise only the driver code gives a clue that the i2c driver matches imx1-i2c, imx21-i2c and vf610-i2c, but not imx31-i2c. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
