[Q] regulators: 3-current-regulated supply

From: Guennadi Liakhovetski
Date: Thu Nov 15 2012 - 02:15:06 EST


Hi

I'm trying to implement a regulator driver for a PMIC [1], and so far I
don't see how it can be mapped to the present regulator API. Most its
parts are pretty simple - DCDC step-down, LDO. The first step-up DCDC
isn't a problem either. It's the second step-up supply, that I'm having a
problem with. It's output voltage can be regulated by using either a
voltage feedback or the three current feedbacks. In the current feedback
mode one has a choice between a manual mode, in which case you just choose
one of the feedbacks and everything is simple again, or in automatic mode.
In the automatic mode one can use any subset of the 3 feedbacks. Then the
PMIC "automatically selects the highest string" (any idea what that means
anyone?) In any case, that means, that the chip uses some algorithm to
pick up one of the feedbacks dynamically at run-time, depending on the
current loads. So, question #1: what should I return from
.get_current_limit()? I don't think there is a way to find out, which
current limit is currently being used or how much consumers consume. #2:
how do I set those 3 limits, resp., what do I do in .set_current_limit()?
Looks like an API extension is needed...

Thanks
Guennadi

[1] http://www.ams.com/eng/content/download/278923/1044357/AS3711_Datasheet_v1_20.pdf
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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