On Fri, Dec 20, 2024 at 07:51:32AM +0000, Tudor Ambarus wrote: > > > On 12/19/24 6:58 PM, Conor Dooley wrote: > > On Thu, Dec 19, 2024 at 03:42:11PM +0000, Tudor Ambarus wrote: > >> Hi, Conor, > >> > >> On 12/19/24 2:11 PM, Conor Dooley wrote: > >>>> There are mailbox clients that can discover the mailbox channel ID at > >>>> run-time. For such cases passing the channel identifier via DT is > >>>> redundant. Add support for referencing controllers solely by node. > >>> I don't really get your implementation, why not just allow #mbox-cells = 0? > >>> That's what's done for things like fixed frequency clocks that only have > >>> a single output. > >> > >> Ah, indeed! > >> > >> instead of: > >> of_parse_phandle(dev->of_node, "mbox", 0); > >> I can do a: > >> of_parse_phandle_with_args(dev->of_node, "mboxes", > >> "#mbox-cells", 0, &of_args) > >> where #mbox-cells = 0; > >> > >> Or ... can I pass NULL for cells_name and make the #mbox-cells property > >> optional and still keeping its requirement of being at least 1? > > > > I think the mbox-cells = 0 approach is preferred, that property is what > > marks it as a mailbox controller after all. Perhaps Rob or Krzysztof can > > comment? > > I think using mbox-cells = 0 is better indeed. In my proposal I > considered the list to always have a single phandle, thus a reference to > a single mailbox controller, whereas it may be possible that clients to > reference multiple mailbox controllers. If so, #mbox-cells needs to be > defined in all the controllers, for consistency reasons, similar to what > happens with fixed clocks, as you already mentioned. Oh right, I had totally forgotten about that, that's a solid argument for the mbox-cells = 0 approach for sure.
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