Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753212AbZDUGH0 (ORCPT ); Tue, 21 Apr 2009 02:07:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751112AbZDUGHL (ORCPT ); Tue, 21 Apr 2009 02:07:11 -0400 Received: from cathcart.site5.com ([74.54.107.137]:37732 "EHLO cathcart.site5.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750907AbZDUGHK (ORCPT ); Tue, 21 Apr 2009 02:07:10 -0400 Message-ID: <49ED628A.4000505@compulab.co.il> Date: Tue, 21 Apr 2009 09:07:06 +0300 From: Mike Rapoport User-Agent: Thunderbird 2.0.0.16 (X11/20080907) MIME-Version: 1.0 To: James Kosin CC: linux-kernel@vger.kernel.org, Mike Rapoport Subject: Re: [RFD] voltage/current regulator consumer interface References: <49EC9709.8070002@support.intcomgrp.com> In-Reply-To: <49EC9709.8070002@support.intcomgrp.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - cathcart.site5.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - compulab.co.il X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1829 Lines: 51 James Kosin wrote: > 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. Suppose you have a handheld device with GPS transceiver. You would like to give user the ability to switch the transceiver on and off. > > James > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- Sincerely yours, Mike. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/