[PATCH 04/10] clk: implement parent pass through functions

Sascha Hauer
2011-04-19T20:58:00Z

On Tue, Apr 19, 2011 at 09:09:10PM +0200, Uwe Kleine-K?nig wrote:
> Hello,
>
> >
> > +1 for letting the core enable/disable and prepare/unprepare the parent
> > clocks. I scanned the different arm clock implementations and they all
> > do it, except the ones which do not implement parents at all.
> Then the question is if all do handle parents in the same way. (i.e.
> in enable do parent first, in disable do child first?)

Yes, they do.

>
> If one layer of indirection is acceptable this can easily be
> accomplished (unless I oversee something):
>
> struct clk_with_parent {
> struct clk clk;
> const struct clk_ops *ops;
> struct clk *parent;
> }
>
> Then the callbacks in clk_with_parent.clk would handle the parent and
> then call the respective callbacks in clk_with_parent.ops.

I fail to see what you are trying to archieve. struct clk already has a ops
pointer, what's the purpose of the additional *ops here?
Other than that I prefer not to hardcode parent pointers. Often enough I
have looked at clock trees and wondered if the clock tree is in sync
with the hardware. When we read the mux values back from the hardware in
clk_get_parent the trees are in sync by definition (modulo refcounting
when you play with the registers somewhere else).

Sascha

--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |