Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756938AbZLNLb3 (ORCPT ); Mon, 14 Dec 2009 06:31:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752552AbZLNLb2 (ORCPT ); Mon, 14 Dec 2009 06:31:28 -0500 Received: from opensource.wolfsonmicro.com ([80.75.67.52]:50434 "EHLO opensource2.wolfsonmicro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750719AbZLNLb1 (ORCPT ); Mon, 14 Dec 2009 06:31:27 -0500 Date: Mon, 14 Dec 2009 11:31:25 +0000 From: Mark Brown To: Juha Keski-Saari Cc: "lrg@slimlogic.co.uk" , "dbrownell@users.sourceforge.net" , "sameo@linux.intel.com" , "linux-kernel@vger.kernel.org" , "De-Schrijver Peter (Nokia-D/Helsinki)" , "Valentin Eduardo (Nokia-D/Helsinki)" Subject: Re: [PATCH 1/1] twl4030-regulator: extend twlreg_info to contain turnon delay and remap Message-ID: <20091214113125.GB21066@rakim.wolfsonmicro.main> References: <1260518031-11192-1-git-send-email-ext-juha.1.keski-saari@nokia.com> <20091211103537.GC18825@rakim.wolfsonmicro.main> <1260774317.31691.20.camel@keskisaa-workstation> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1260774317.31691.20.camel@keskisaa-workstation> X-Cookie: Too much is not enough. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1205 Lines: 23 On Mon, Dec 14, 2009 at 09:05:17AM +0200, Juha Keski-Saari wrote: > has been turned on. The DM also quotes a maximum wakeup time for > returning from sleep to full output, but that delay is much shorter. For > some regulators the turnon delay is theoretically long enough for the > reg_enable to return to the driver noticeably earlier than the regulator > output is actually at target level. OK. This ramp rate thing is a general issue for regulators, especially those that are controlled via GPIOs rather than I2C since for them the control interface takes approximately zero time to respond. Ideally we want to do something slightly more involved than what you've got here since if you're turning on more than one regulator at once it'd be nice to be able to allow all the supplies to ramp in parallel rather than serialising everything. I've got a patch half done for this which I should try to finish off and post soon but for now this should be OK. -- 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/