Messages in this thread | | | From | Rob Herring <> | Date | Thu, 21 Jan 2021 11:45:51 -0600 | Subject | Re: [RFC PATCH 4/7] irqchip/apple-aic: Add support for Apple AIC |
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On Thu, Jan 21, 2021 at 4:38 AM Arnd Bergmann <arnd@kernel.org> wrote: > > On Thu, Jan 21, 2021 at 10:48 AM Linus Walleij <linus.walleij@linaro.org> wrote: > > > > Hi Mohamed, > > > > thanks for your patch! > > > > On Wed, Jan 20, 2021 at 2:31 PM Mohamed Mediouni > > <mohamed.mediouni@caramail.com> wrote: > > > > > +properties: > > > + compatible: > > > + items: > > > + - const: apple,aic > > > > However weird it may seem, Apple is not in the file > > Documentation/devicetree/bindings/vendor-prefixes.yaml > > > > (I think it's weird because I remember clearly that they have been > > using device tree for PPC since ages.) > > > > Could you add this 2-liner to that file and send it directly to > > DT binding maintainers as a single patch as a preparation? > > Choosing the vendor prefix here is going to be a little tricky > and non-obvious. > > Background: > > Traditionally, it should have been the stock ticker symbol of the > company (clearly only publicly traded companies would be able > to produce a Unix capable computer, right?), but there were > already inconsistent: IBM used "ibm" (in small letters), Sun > used "SUNW" (in capitals) but in 2007 changed the stock ticker > symbol to "JAVA", obviously without changing the firmware bindings. > > Apple traditionally used "AAPL" (also in caps) in the device tree, > and there is one remnant of that in the M1 device tree, in the form > of the "AAPL,phandle" property in each node, which corresponds > to our "linux,phandle". (phandles were introduced as properties in > both of the flattened DT formats, .dtb and apple's own format). > There are also "AAPL,unit-string properties and some device_type > strings (AAPL,display-crossbar, AAPL,atc-dpxbar, ...) in the M1 DT, > and the CPU nodes (and only those) use "apple" in small letters > as in "apple,icestorm","ARM,v8". The other nodes tend to not have > a vendor prefix, but a lot use a subsystem name as the prefix, such > as compatible="gpio,t8101" or compatible="tempsensor,t8020". > > Since Apple are already using both the "AAPL" and the "apple" > prefix themselves, I have a bad feeling about reusing either of > them for defining the devicetree.org bindings that we add to > linux/Documentation/devicetree/bindings. The question is: if > not "apple", what else should we use here?
IMO, 'AAPL' as that is what is already in use in the kernel. I don't see why it matters at all what Apple is using. It might if we used any of the ADT as-is, but I don't see that happening from what I've seen.
Rob
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