Hi Arnd, Thanks for taking the time to explain this. On Fri, 14 Nov 2014, Arnd Bergmann wrote: <snip> > > address of the device's resources within the address space defined by its parent bus"). > > You will also have to add an appropriate 'ranges' property then. > > > Or maybe you meant, if I want to keep the picophy node where it is (under soc), I need to stop using the reg > > property? > > That would also be possible, just put the register numbers into your 'st,syscfg' > property after the phandle, and leave the reg property empty then. I think this is the best approach and whay I will do, as it would also extend well to devices with sysconfig registers in different banks. > > > The other problem I was describing is a device with some memory mapped registers and some > > sysconfig registers you can find examples already upstream in stih416.dtsi file with the > > ethernet0 and miphy365x_phy nodes. > > > > Here the first 1/2 reg properties are expressed as a 32 bit physical address and size (meets the spec definition), > > and the last is expressed as a sysconfig offset and size (which AFAIK doesn't match the spec definition). > > This change in address space is however documented in the bindings documentation. > > > > How should devices which have multiple address spaces ideally be handled? > > There should at most be one 'reg' address space, so put it under the node whose > bus these refer to. Put all offsets that are relative to a syscon link into > the phandle that refers to the syscon device, or hardcode the offsets in the > driver. Ok makes sense. > > > From looking around in the source I see a few different ways people have done this: - > > > > 1) Some drivers encode the data statically into the source and make a decision based on compatible string. > > 2) Some drivers add a couple of extra dt properties to encode the offset (spifsm in stih416) > > 3) Some drivers mix address spaces in the reg properties (examples given above) > > 3) Probably some other ways I've not found yet > > > > Is there a blessed way of doing this? It would be nice at least for all the drivers in STI to be doing > > it the same as currently there seems to be a mix of implementations. > > You can do 1 or 2, not 3. Yep got it. One last question, what are the rules about updating ethernet and miphy365 over to using this method for there sysconfig registers? regards, Peter. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
