On Thu, Jan 12, 2012 at 11:44 AM, Turquette, Mike <[email protected]> wrote: > On Thu, Jan 12, 2012 at 2:07 AM, Jamie Iles <[email protected]> wrote: >> On Wed, Jan 11, 2012 at 09:46:58PM -0700, Grant Likely wrote: >>> On Tue, Jan 10, 2012 at 2:33 PM, Jamie Iles <[email protected]> wrote: >>> > On Mon, Dec 12, 2011 at 03:02:04PM -0700, Grant Likely wrote: >>> > I'm about to start trying to get this and Mike's common struct clk >>> > patches working on picoxcell, and the one thing I'm not understanding at >>> > the moment is how to handle the tree itself. Currently I was planning >>> > on iterating over all clocks and finding a named input clock "ref" or >>> > "input" perhaps. This would be fine for picoxcell, but I guess more >>> > complicated chips may need something else. >>> >>> It might be useful to have something like of_irq_init() for setting up >>> initial clocks, but the solution feels inelegant to me. I suspect >>> that there will be end up being intertwined init order dependencies >>> between clocks and irqs and other early setup stuff that could be >>> handled better. Again, I need to think about this some more. There >>> might need to be something like an of_early_probe() call that accepts >>> a match table of compatible values and setup functions with some logic >>> or data to resolve dependencies. The trick will be to not end up with >>> something complex. I'll need to think about this more... >> >> Yes, probably not an easy problem to solve, especially for the platforms >> where the parent can change at runtime. >> >> I wonder if an of_clk_init() could take a platform callback, so that >> of_clk_init() goes of and creates a struct clk for each clk in the DT, >> then for each registered clock calls a platform specific callback which >> returns the parent (if any). It feels like a fairly platform specific >> problem to me. > > Based on Thomas' feedback I'm removing the requirement for clocks to > be registered in-order with clk_init(). Any clock that cannot resolve > it's parent within clk_init() (via the .get_parent callback, or > otherwise having .parent statically initialized) will be put into an > orphaned clocks list, which will be walked every time a new clock is > registered. Hurray for n^2 solutions. > > Does the above help with the of_clk_init problems?
It does. > One final data point: I certainly plan on allowing for statically > allocated clocks to live alongside DT clocks. In fact the clock trees > on OMAP are so large that there is some discussion about having some > of the clocks statically allocated and some in DT, but I don't know > what that split looks like right now. I don't enjoy the idea of > packing 200+ of any entity into a .dts blob. I'm okay with that. _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
