From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [patch 2.6.29-rc5-omap-git] mach-omap2/mmc-twl4030: fix for vmmc = 0 Date: Wed, 25 Feb 2009 11:45:07 +0200 Message-ID: <49A51323.1030701@nokia.com> References: <200902231014.26352.david-b@pacbell.net> <49A3DEA8.1050909@nokia.com> <200902241213.06500.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.nokia.com ([192.100.122.233]:62428 "EHLO mgw-mx06.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761180AbZBYJpj (ORCPT ); Wed, 25 Feb 2009 04:45:39 -0500 In-Reply-To: <200902241213.06500.david-b@pacbell.net> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: David Brownell Cc: "linux-omap@vger.kernel.org" David Brownell wrote: > On Tuesday 24 February 2009, Adrian Hunter wrote: >> David Brownell wrote: >>> From: David Brownell >>> >>> Resolve longstanding issue noted by Adrian Hunter: confusion >>> between settting VSEL=0 (which is 1.8V on MMC1) and poweroff. >>> >>> Also, leave VSEL alone if we're just powering the regulator off. >>> >>> Signed-off-by: David Brownell >>> --- >> Looks fine to me, but I wonder if you know why the regulator is >> turned on (DEV_GRP) and then the voltage is selected (DEDICATED). > > History, I'd guess. I seem to remember some sequencing > constraint, but couldn't find it when last I sought it > out in the reference manual. What about section 5.5.1 item 6? >> Wouldn't it make more sense the other way around? > > I had the same thought. Eventually I'd like this code > to mostly wither away ... using the regulator framework > for the hsmmc driver will eliminate most of the remaining > bits of twl4030-specific code. So I'd just leave it be > for the moment. > > >> Doesn't the new regulator framework do it that way? > > No; setting voltage and enabling are distinct operations. Perhaps, but there are features like regulator constraints, or the Virtual regulator that do set the voltage and then enable.