Re: [Query]set clk rate must operate its coordinated clock

["Heiko Stübner" <heiko@sntech.de>]

Hi Mike,

Am Freitag, 11. M=E4rz 2016, 08:51:52 schrieb Michael Turquette:
> Quoting Jisheng Zhang (2016-03-08 23:24:20)
> > I have the following clk case which I dunno the elegant solution:
> >=20
> >=20
> > cpuclk have two parents: cpupll and refclk. When set the cpuclk fre=
q, we
> > have to set its parent's freq, I.E cpupll freq. But before changing=
 the
> > cpupll's freq, we should set its refclk as its parent firstly.
> >=20
> > AFAIK, this is a common case, I have seen such requirement in rockc=
hip,
> > samsung clk driver. They solve this by notifier, but as pointed out=
 by
> > Michael in
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/351=
565.ht
> > ml
> >=20
> > "This is also a hack and it points towards some missing infrastruct=
ure in
> > the clock framework."
> >=20
> > I also don't like the notifier solution, I believe the elegant solu=
tion
> > could be using the coordinated clock infrastructure. So what's the =
status
> > of this infrastructure? I can test, and I can even add some code to=
 make
> > it be ready to be merged if you guide me ;)
>=20
> Thanks for the email. I hope to finish that feature before ELC. I hav=
e
> Cc'd Pi-Cheng Chen from Mediatek who is also interested in coordinate=
d
> clock rates.

pulling this up again, did this materialize yet? :-)

Because it looks like on Rockchip we're getting yet another clock that =
needs=20
special handling (set_rate needs to go through the trusted-firmware, wh=
ile=20
reading stays the same) which might profit from that as well.


Heiko