On Thu, Nov 17, 2011 at 06:37:26PM +0000, Dave Martin wrote: > On Thu, Nov 17, 2011 at 04:05:37PM +0000, Russell King - ARM Linux wrote: > > You do understand that system_rev is for the system _revision_ not for > > some kind of system ID. For example, it's to identify whether we're on > > a revision 4, 5 or 6 system. > > > > However, with DT the differences in system revision should be encoded > > into the DT itself, and the kernel should not be making choices about > > the hardware off this. > > I can't comment on whether this is an abuse of system_rev, since I'm > not too familiar with that. > > I feel that Whether the value of the V2M_SYS_ID register should be put > in the DT is more doubtful though: the DT must describe the hardware > which cannot be probed.
That is exactly my point - but we don't want V2M_SYS_ID controlling what hardware is there because then you'll end up having _drivers_ having to be aware of the system revision. Instead, the differences in device IP - when they're not discoverable from the device itself - should be encoded in DT to allow the device IP to be reused on different platforms which may not even have a V2M_SYS_ID register. That's what my objection is about: nothing should be using the overall system revision to determine anything about it. _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss