Message-ID: <49EC9709.8070002@support.intcomgrp.com>
Date: Mon, 20 Apr 2009 11:38:49 -0400
From: James Kosin <jkosin@beta.intcomgrp.com>
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To: linux-kernel@vger.kernel.org
Subject: Re: [RFD] voltage/current regulator consumer interface
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Mike Rapoport wrote:
> Hi,
> 
> Recently there was a brief discussion on linux-arm-kernel list [1] about
> controlling voltage regulator state in cases when there is no consumer device
> for a particular regulator.
> 
> I have some thoughts but I'd like to know people opinion before I start
> implementation.
> 
> Problem
> -------
> The regulator framework API provides ability to control the state of
> voltage/current regulators from within the kernel. Usually the regulator
> supplies power to a device and device driver or some hooks to the platform code
> from the device driver manipulate the regulator state. However, the regulator
> framework does not have userspace ABI that allows regulator state modifications.
> Lack of this ABI prevents fine-grained control for power consumption of devices
> such as GPS trancievers and GSM modems. Moreover, in SoC based systems it is
> possible to switch on/off power to entire subsystem when it is not used.
> 


I'd also ask the question, Why?
If exposing to user space it leaves the possibility of damaging hardware
or completely frying a board.

James
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