On 07/16/2013 12:30 PM, Thomas Petazzoni wrote: > Dear Nicolas Ferre, > > On Tue, 16 Jul 2013 10:46:28 +0200, Nicolas Ferre wrote: > >>> Ok, that make sense. I will use compatible names for the capabilities in >>> next version. Thanks. >> >> Hold on a little bit Josh, I know that Jean-Christophe is not in favor >> of the use of multiple compatible strings. So, as the code is already >> there, let's wait and see if we find another argument... > > I've asked exactly this question last week at Linaro Connect during the > ARM SoC consolidation panel/discussion, where Grant Likely, Arnd > Bergmann, Olof and others were answering Device Tree related questions. > > My question, which precisely had the at91-adc DT binding in mind was > precisely whether we should use different compatible properties to > identify different revisions of an IP block and let the driver handle > those differences, or whether the DT binding should provide sufficient > properties (register offsets, bit numbers, etc.) to make the driver > independent of the IP revisions. And clearly, the answer was that > different compatible properties should be used to identify the > different versions of the IP block, and the driver should abstract out > the differences. I.e, was has been done for at91-adc is completely the > opposite of the best practices for Device Tree on ARM. > > See > http://www.youtube.com/watch?v=zF_AXLgkFy4&feature=player_detailpage#t=1581s > where I ask exactly this question, and get answers from Olof Johansson > and Grant Likely. They clearly say that the solution of having separate > compatible properties and a driver that handles the differences is the > way to go. So the way at91-adc (and possibly other at91 drivers) is > using the Device Tree is wrong, there should have been multiple > compatible properties. It's a shame because this is something we did say > when we submitted at91-adc and during the reviews, but the maintainer > wasn't listening to our comments... > Thanks for getting some clarity on this Thomas. So I'll ask the somewhat obvious question - how do we unwind from where we are to where we want to be wrt to the bindings? -- 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
