Hi Heiko,
On 11/07/2014 05:06 AM, Heiko Stübner wrote:
Hi Kever,
Am Dienstag, 4. November 2014, 15:52:34 schrieb Kever Yang:
we are going to make a clock usage solution for rk3288:
1. CPLL and GPLL always not change after assign init;
2. NPLL default as 500MHz, may used for most scene;
3. NPLL may be changed by VOP(HDMI) clock for some special
frequency requirement.
I test it with rk3288 evb on top of Heiko's clk-for-next
In general I'm not really sure if allowing one component to arbitarily change
a shared clock wouldn't result in trouble.
At the moment only dclk_vop0 is included in your series, while the hdmi
controller can connect to both vop0 and vop1.
And as Doug mentioned the gpu also has the npll as one possible source.
I think the problem GPU HANGs with 480MHz clock from usbphy has
been fixed with my patch to gerrit:
https://chromium-review.googlesource.com/#/c/229554/
Looking through the clock-tree there are a lot more components possibly using
(or wanting to use) the npll: of course the VOPs, the edp, hdmi, isp, hevc,
gpu, tsp uart0 and gmac. So I'm slightly uncomfortable with somehow reserving
the npll for VOP0 alone.
It's true that I customized the usage of npll for VOP0 when we need some
very special frequency, but it doesn't means other modules can't use the
npll, it will always decided by clock core for module clocks that which
parent
is the best.
I'll be very happy if there is a better solution for this situation, and any
suggestion is welcome.
- Kever
But I also don't see a different way to get these frequencies right now.
Heiko
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