On 21/08/15 00:53, Michael Welling wrote: > On Fri, Aug 21, 2015 at 12:48:23AM +0200, 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. >> >> 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. >> > > Okay. > > Acked-by: Michael Welling <mwelling@xxxxxxxx> Applied to the togreg branch of iio.git Thanks, Jonathan > >> [0]: https://www.power.org/documentation/epapr-version-1-1/ >> >> Best regards, >> -- >> Javier Martinez Canillas >> Open Source Group >> Samsung Research America > -- > 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 > -- 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
