On Tue, 17 Jul 2018, at 14:26, Benjamin Herrenschmidt wrote: > On Mon, 2018-07-16 at 07:55 -0600, Rob Herring wrote: > > If that data is one set per SoC, then i'm not that concerned having > > platform-specific data in the driver. That doesn't mean the driver is > > not "generic". It's still not clear to me in this thread, how much of > > this is board specific, but given that you've placed all the data in > > an SoC dtsi file it seems to be all per SoC. > > So Rob, I think that's precisely where the disconnect is. > > I think we all (well hopefully) agree that those few tunables don't fit > in any existing subystem and aren't likely to ever do (famous last > words...). > > Where we disagree is we want to make this parametrized via the DT, and > you want us to hard wire the list in some kind of SoC driver for a > given SoC family/version. > > The reason I think hard wiring the list in the driver is not a great > solution is that that list in itself is prone to variations, possibly > fairly often, between boards, vendors, versions of boards, etc... > > We can't know for sure every SoC tunable (out of the gazillions in > those chips) are going to be needed for a given system. We know which > ones we do use for ours, and that's a couple of handfuls, but it could > be that Dell need a slightly different set, and so might Yadro, or so > might our next board revision for that matter. > > Now, updating the device-tree in the board flash with whatever vendor > specific information is needed is a LOT easier than getting the kernel > driver constantly updated. The device-tree after all is there to > reflect among other things system specific ways in which the SoC is > wired and configured. This is rather close... Not sure this helps, but I feel that the proposal pretty closely matches what's described in Documentation/devicetree/bindings/mfd/mfd.txt. It's intended that nodes using the bindings I'm proposing are children of a 'compatible = "syscon", "simple-mfd"' node (this is the case with the features we're hoping to describe for our SoC). I should explicitly call that out. But to go on, "simple-mfd" is effectively an alias of "simple-bus", which means its intended to match child node compatibles to drivers provided by the kernel. If we shouldn't be describing minor features of a SoC in the devicetree, doesn't this invalidate the case for simple-mfd? What is the *correct* use of simple-mfd? When is it not used to expose minor features in set of "miscellaneous system registers"? Why doesn't this proposed case fit? Cheers, Andrew -- 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
