On Tue, Aug 26, 2014 at 09:42:08AM +0100, Grant Likely wrote: > On Mon, 25 Aug 2014 15:37:16 +0200, Thierry Reding <thierry.reding@xxxxxxxxx> wrote: [...] > > There are somewhat standardized bindings for the above and especially > > for bindings of the type that clocks implement this is trivial. We can > > simply iterate over each (phandle, specifier) tuple and check that the > > corresponding clock provider can be resolved (which typically means that > > it's been registered with the common clock framework). > > > > For regulators (and regulator-like bindings) the problem is somewhat > > more difficult because they property names are not standardized. One way > > to solve this would be to look for property names with a -supply suffix, > > but that could obviously lead to false positives. One alternative that I > > think could eliminate this would be to explicitly list dependencies in > > drivers. This would allow core code to step through such a list and > > resolve the (phandle, specifier) tuples. > > False positives and negatives may not actually be a problem. It is > suboptimal, certainly, but it shouldn't outright break the kernel. There could be cases where some random integer in a cell could be interpreted as a phandle and resolve to a struct device_node. I suppose it might be unlikely, but not impossible, that the device_node could even match a device in the correct subsystem and you'd get a wrong dependency. Granted, a wrong dependency may not be catastrophic in that it won't lead to a crash, but it could lead to various kinds of weirdness and hard to diagnose problems. Thierry
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