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. [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
