On Wed, 2018-06-13 at 02:16 +0300, Andy Shevchenko wrote: > On Wed, Jun 13, 2018 at 1:58 AM, Benjamin Herrenschmidt > <benh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, 2018-06-12 at 19:53 +0300, Andy Shevchenko wrote: > > > > > > > > It feels like a wrong approach. > > > > > Can OF graph help here? Would it be better approach? > > > > > > > > I don't quite understand what your objection is nor what "OF graph" > > > > is... > > > > > > There is no objection per se, just a doubt that this is a right thing to do. > > > I might be wrong, of course. > > > > > > OF graph nodes is a special API that allows you to access like you > > > said "different node of device-tree". > > > https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/graph.txt > > > > So I had a look and this is just an example on how to use phandles to > > link ports and endpoints... I fail to see how that relates to what this > > patch does. > > Because your patch does nothing except another layring of the existing APIs. I'm really having a hard time understanding what you are going on about.. Yes, it's a helper that combines two existing API functions, the goal being to generally replace the use of the existing of_iomap whenever possible. It makes sense and makes callers simpler and less bug prone. > > > In the driver I'm doing for example, I do use a similar technique to > > "point" to the other node. In this case, this is a coprocessor in the > > SoC and I'm linking to the node that represent its interrupt controller > > (and its not a full fledged OS running there so we don't have a full > > interrupt tree for it). > > Hmm... So, you are trying to solve problem with other methods which > might be not so suitable at all? Again, I cannot understand what you are going on about, what is "not suitable" to what purpose ? It's fairly common for nodes to point to each other. We've been doing that since the dawn of the device-tree. In this case, we have a coprocessor bound to a device and pointing to its interrupt controller, and we need to get to that and map it, I fail to see what the issue is and in what way this is "not suitable". But there are many other uses of things like of_iomap() which could benefit from switching to devm_of_iomap() and thus getting the automated cleanup on exit and appropriate request of the memory resource. (hint: I wrote of_iomap and a good bulk of what's in drivers/of/address.c... Ben. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
