Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752011AbZDUKFg (ORCPT ); Tue, 21 Apr 2009 06:05:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753208AbZDUKF0 (ORCPT ); Tue, 21 Apr 2009 06:05:26 -0400 Received: from cassiel.sirena.org.uk ([80.68.93.111]:48747 "EHLO cassiel.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753170AbZDUKFZ (ORCPT ); Tue, 21 Apr 2009 06:05:25 -0400 Date: Tue, 21 Apr 2009 11:05:24 +0100 From: Mark Brown To: James Kosin Cc: linux-kernel@vger.kernel.org Subject: Re: [RFD] voltage/current regulator consumer interface Message-ID: <20090421100524.GC25828@sirena.org.uk> References: <49EC9709.8070002@support.intcomgrp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49EC9709.8070002@support.intcomgrp.com> X-Cookie: Rubber bands have snappy endings! User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: broonie@sirena.org.uk X-SA-Exim-Scanned: No (on cassiel.sirena.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1092 Lines: 21 On Mon, Apr 20, 2009 at 11:38:49AM -0400, James Kosin wrote: > > 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. There are some classes of device found in embedded systems which do things like provide an essentially separate system which interacts with the host system via something like a serial port. These devices are normally controlled entirely from user space which is fine with static power configuration but if you want to provide regulator control for these devices you need to either move the control of the device into the kernel or expose the regulators the device uses to userspace. -- 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/