On 20/08/15 23:48, Javier Martinez Canillas wrote: > Hello Michael, > > On 08/21/2015 12:29 AM, Michael Welling wrote: >> On Fri, Aug 21, 2015 at 12:02:40AM +0200, Javier Martinez Canillas wrote: >>> Hello Michael, >>> >>> On 08/20/2015 10:09 PM, Michael Welling wrote: >>>> On Thu, Aug 20, 2015 at 09:07:26AM +0200, Javier Martinez Canillas wrote: >>>>> The driver has an OF id table but the .of_match_table is not set so >>>>> the SPI core can't do an OF style match and the table was unused. >>>>> >>>> >>>> Is an OF style match necessary? >>>> >>> >>> Did you read the cover letter [0] on which I explain why is needed to >>> avoid breaking module autoloading in the future? Once the SPI core is >>> changed by RFC patch 18/18? (you were cc'ed in the cover letter BTW). >> >> Well I have read it now. :) >> > > Great :) > >>> >>>> I have been using devicetree and it matches based on the .id_table. >>>> >>> >>> Yes it fallbacks to the .id_table or the driver name but the correct >>> thing to do for devices registered by OF, is to match using the >>> compatible string. >>> >>>> Couldn't we just remove the mcp320x_dt_ids table instead? >>>> >>> >>> No, that is the wrong thing to do IMHO since the compatible string >>> contains both vendor and device name whle the .id_table only contains >>> a device name. >>> >>> So it makes sense to match using the compatible string and also report >>> the OF modalias information to user-space. >>> >>> Otherwise what's the point of the vendor in the compatible string for >>> SPI devices? You can just use "bar" instead of "foo,bar" as a string. >>> >> >> Well then shouldn't the patch include adding the vendor to the compatible >> string? >> > > Well, I was talking in general. You are right that this specific driver does > not have a vendor prefix for the compatible strings. This is incorrect > according to the ePAPR document [0]. > > However, these compatible strings are already documented as a DT binding doc > in Documentation/devicetree/bindings/iio/adc/mcp320x.txt so I don't know > what is the correct thing to do in this situation. Take the view the old version is wrong but needs to be supported and add also the corrected strings + document them. cc'd The device tree list for any more comments on this. > > Changing the compatible string will break old DTB with newer kernels and that > is a no go. But that doesn't invalidate what I said since once the SPI core > is changed and report OF modalias, you will need a MODULE_DEVICE_TABLE(of,...) > regardless if the compatible string has a vendor prefix or not. > > [0]: https://www.power.org/documentation/epapr-version-1-1/ > > Best regards, > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
