[U-Boot] [PATCH 1/3] arm: tegra20: implement early pmic rail configuration

Marcel Ziswiler marcel.ziswiler at toradex.com
Fri Aug 21 01:06:41 CEST 2015


On 20 Aug 2015 22:00, Stephen Warren <swarren at wwwdotorg.org> wrote:

> Does the CORE rail get adjusted by DVFS? Hopefully if it does, it is
> never set so low that AVP operation at reset is impossible...

Exactly.

> > +     udelay(1000);
>
> all the delays in this patch seem very large. What drove the choice of
> the delay values?

Three things: I2C transfers at that speed will take at least around some 3 to 4 hundred us to complete so we stay at the save side. Plus the T30 equivalent file uses the exact same delays so it can't be that wrong. My testing also showed that setting it anywhere much lower will cause reliability issues.


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