From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751981Ab2DTNBj (ORCPT ); Fri, 20 Apr 2012 09:01:39 -0400 Received: from opensource.wolfsonmicro.com ([80.75.67.52]:48605 "EHLO opensource.wolfsonmicro.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750923Ab2DTNBi (ORCPT ); Fri, 20 Apr 2012 09:01:38 -0400 Date: Fri, 20 Apr 2012 14:01:34 +0100 From: Mark Brown To: Jassi Brar Cc: linux-kernel@vger.kernel.org, lrg@ti.com Subject: Re: [PATCH] regulator: Provide a check for dummy regulator Message-ID: <20120420130134.GA5957@opensource.wolfsonmicro.com> References: <1334829097-32084-1-git-send-email-jaswinder.singh@linaro.org> <20120419124204.GE3046@opensource.wolfsonmicro.com> <20120419162905.GA3084@opensource.wolfsonmicro.com> <20120420114602.GB3259@opensource.wolfsonmicro.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="NzB8fVQJ5HfG6fxh" Content-Disposition: inline In-Reply-To: X-Cookie: You'll be sorry... User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --NzB8fVQJ5HfG6fxh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Apr 20, 2012 at 05:59:42PM +0530, Jassi Brar wrote: > That's what I have been trying to fix. My example might be fictitious but > I have a real scenario with omap_hsmmc (I was avoiding getting into that). > The dummy not just provide a place holder data structure for missing definition > of an available supply, but it also masks the fact that there might indeed be no > supply at all on the given machine. > As I said, atm the only option for a consumer is to know it via PD/DT. No. You're failing to understand what dummy regulators are for. To repeat yet again you're not supposed to actually use dummy regulators, you're supposed to fully specify the regulators on your platform. As I've said several times now dummy regulators are just a crutch to hold systems together, if they're not working out the solution is to turn them off and even if they are working out turning them off is still the best thing to do. The problems you are seeing are exactly why this is the case. > The benefit is magnified by the fact that, for a given circuit, at > least theoretically, > there is no limit to the number/combination of supplies that could be controlled > by inserting a regulator. And that could lead to a very noisy PD/DT. No, any given circuit is going to have a very clear set of things that can be controlled by a regulator, and most chips have a fixed set of supplies they always need so it's very simple from their point of view. --NzB8fVQJ5HfG6fxh Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJPkV4mAAoJEBus8iNuMP3dQJYP+QGes/U12MsBcOkSkrMJ8Whf tgn6cpPD7dC9U5se/O2wCh4/MT9aGlSw3irflGbianF18sFLfhWzcGy0a+0TcYLw nnNhy6lUgZRgCnW23ImJks/3hat5krXibmpayQ8ZjyTJQHWyOrY8UGn18Dlks4wM cTwMnUajLAiy1tmv0oOZMrf1bSdV/i35Z5o3iqzfRpojRocOM/dTBZU6SAD5wNkB Ckb+NrU/9oMZVBOhRg31JlZj6K84z6rrH0EMvwuY6cQsZWgufx306wIbD3cPRRID t3Qj/jXCHXgX3LVupqSXPUg4xtm7AWEgjcDXwYDXi41v5oSlmksMMODQqdR6kIRH dMjSe1u+d8kDG/TzvVJ7OFOXqT9a9gbvxaOjo8v5YsyelOEdsjZ6cYd+a9JlNh9x G9UmUsMRFnp8Fc5uQVdZn6JyUrn4GHTw2b8N7YNPGZUQ2dYYMIDtGN4nw6uu/wH7 M7t/XSJNLnw3jsikOEs3b33VddLFG0eInHV2YOBpBhcpSnk+IONcl99dScVsDGwX QSFhmgpFs4NEnBZAmGRHN8XnWUyecl9PvPC5TWvhUypCzHFJg3nos9L2BeLW7SPm vDIERmHDuUXV6XFiV39wgcQkmbH9w5RAGMgjtsO3SacElLzuRMZ7KJk6DGz5UsUD qfD/tM+EY7aR4KmPiVKr =Q9CA -----END PGP SIGNATURE----- --NzB8fVQJ5HfG6fxh--