From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964849AbaH0Swz (ORCPT ); Wed, 27 Aug 2014 14:52:55 -0400 Received: from mail-wi0-f180.google.com ([209.85.212.180]:54201 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935656AbaH0Swy (ORCPT ); Wed, 27 Aug 2014 14:52:54 -0400 Message-ID: <53FE2901.50508@gmail.com> Date: Wed, 27 Aug 2014 20:52:49 +0200 From: Tomasz Figa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Mark Brown CC: Javier Martinez Canillas , Doug Anderson , Olof Johansson , Yuvaraj Kumar C D , linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] regulator: max77802: set opmode to normal if off is read from hw References: <1409053061-22568-1-git-send-email-javier.martinez@collabora.co.uk> <53FE2446.3040402@gmail.com> <20140827183733.GN17528@sirena.org.uk> <53FE25EB.7060702@gmail.com> <20140827184705.GO17528@sirena.org.uk> In-Reply-To: <20140827184705.GO17528@sirena.org.uk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27.08.2014 20:47, Mark Brown wrote: > On Wed, Aug 27, 2014 at 08:39:39PM +0200, Tomasz Figa wrote: >> On 27.08.2014 20:37, Mark Brown wrote: > >>> That's essentially the situation the patch is trying to fix - if we boot >>> and the regulator is off there's no way to figure out what the operating >>> mode would have been so we have to pick something. If you've got an >>> idea for something better to do... > >> Probably the only way to correctly handle this is to specify the right >> operating mode in DT (after defining a binding for it). > > I'm not convinced that's worth it - chances are that if anything changed > the mode it was a previously running Linux which will most likely be > doing the same things when it starts running anyway. > The previously running Linux would have changed the opmode accidentally, due to hardware design of PMIC chip, which doesn't allow powering off a regulator in other way than setting opmode to OFF. If you provide the "active" opmode to that Linux, after a warm reboot it will be able to power on such regulator to correct opmode, without defaulting it incorrectly to NORMAL.