[Openec] Which pins to switch when for switching on an XO?

[Richard A. Smith]

Frieder Ferlemann wrote:

> Just to show the kind of problems where I'm stuck:
> F.e. LaptopPowerB2.pdf shows MAIN_ON being an Output of
> the EC (which it is not (according to the register setting

Its both. It changes during the boot phase.  Details are in the CS5536 
docs.  On boot its an input (to the CS5536) and then it changes to an 
output when the laptop firmware enables it as a power management pin.

So the EC drives the signal when the CS5536 has been powered off but 
then switches to an input.

> So long story short, information like:
> 
> On Suspend/Resume/Run, B1-Bx:
> Pin A of IC B drives Pin C of IC D (..), needs voltage E
> being stable, switches on voltage F with a nominal
> value of G (wanted to be stable to H%) with a time
> constant of K milliseconds

The best place to get a first round guess of this info is by reading all 
the CS5536 docs.

-- 
Richard Smith  <richard at laptop.org>
One Laptop Per Child