Messages in this thread | | | From | Måns Rullgård <> | Subject | Re: [PATCH 2/3] devicetree: add binding for Aurora VLSI NB8800 Ethernet controller | Date | Mon, 26 Oct 2015 13:54:10 +0000 |
| |
Marc Gonzalez <marc_gonzalez@sigmadesigns.com> writes:
>>> So I should write something like this in my DT? >>> >>> eth0: ethernet@26000 { >>> compatible = "sigma,smp8734-ethernet", "sigma,smp8640-ethernet", "aurora,nb8800"; >>> >>> Hmmm, you mention this below, but you used "sigma,smp8759-ethernet". >>> What about earlier chips? >> >> OK, how about this scheme then: >> >> - Device trees list the exact chip, the chip family, the oldest >> compatible family, and finally the basic "aurora,nb8800". For the >> SMP8759 that would look like this: >> "sigma,smp8759-ethernet", "sigma,smp87xx-ethernet", "sigma,smp864x-ethernet", >> "aurora,nb8800" > > AFAICT, the list of tango4 chips is (in chronological order) > > 8910, 8734, 8756, 8758, 8759 > > The problem I see is that Sigma already has plans for non-tango4 > 87xx SoCs (two in fact: 8760 and 8762, as far as I've heard). > (What a mess.) > > I would think the "chip family" needs to use the code-name like > tango3 or tango4 (for lack of a better discriminant). > > Also, (purely hypothetical) suppose something changed in 8756 and up. > How would the 8758 pick up the improvement, but not the 8734? > > I'm also confused, because I thought I read somewhere not to use > wildcards in compatible strings... <Looking> It was there: > http://devicetree.org/Device_Tree_Usage#Understanding_the_compatible_Property > (Sorry, some of this stuff is a bit hard for me to grok.)
Right, and you just illustrated why wildcards are bad. Sorry for the confusion. I should have known better than to look at existing bindings. Let's drop that idea.
Let's try something else:
Device trees list the exact chip, the oldest chip with the same features, and the oldest compatible chip. From the sound of things, that means the smp8759 should use "sigma,smp8759-ethernet", "sigma,smp8910-ethernet", "sigma,smp8642-ethernet", "aurora,nb8800".
> Finally, I think what you decide to do can also be done for the > interrupt controller, right?
Sure, the same scheme should be used for all on-chip devices.
-- Måns Rullgård mans@mansr.com
| |