Date: Thu, 15 Nov 2012 11:10:08 +0100 (CET)
From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
cc: linux-kernel@vger.kernel.org, Liam Girdwood <lrg@ti.com>
Subject: Re: [Q] regulators: 3-current-regulated supply
In-Reply-To: <20121115071838.GI7599@opensource.wolfsonmicro.com>
Message-ID: <Pine.LNX.4.64.1211151103540.684@axis700.grange>
References: <Pine.LNX.4.64.1211150749290.684@axis700.grange>
 <20121115071838.GI7599@opensource.wolfsonmicro.com>
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Hi Mark

On Thu, 15 Nov 2012, Mark Brown wrote:

> On Thu, Nov 15, 2012 at 08:15:15AM +0100, Guennadi Liakhovetski wrote:
> 
> > 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. 
> 
> This almost certainly has no other function than to drive a LED string
> for a backlight; it's not sensible to represent it via the regulator
> framework at all.  Just implement it as a backlight and/or LED driver
> and have done with it unless you can find some other use for it.

Hm, interesting. In my case it is of course a backlight power source, but 
wouldn't it be too limiting to also implement it as a backlight driver? I 
guess I will do that, I'm not too interested in implementing something 
hugely generic, for which I have no use either, just wondering... So, I 
would be hiding all the flexibility in this case in platform data, 
including the selection of the feedback method (voltage vs. current), 
overvoltage protection and pins used... I guess, I'll just begin with 
implementing just one mode, the one used on my board and see if any other 
modes are ever needed.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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