Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752422AbdF3MOA (ORCPT ); Fri, 30 Jun 2017 08:14:00 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:54374 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752360AbdF3MMw (ORCPT ); Fri, 30 Jun 2017 08:12:52 -0400 Date: Fri, 30 Jun 2017 13:12:36 +0100 From: Mark Brown To: Chen-Yu Tsai Cc: Viresh Kumar , "Enrico Weigelt, metux IT consult" , Rafael Wysocki , Vincent Guittot , Rob Herring , Greg Kroah-Hartman , Stephen Boyd , linux-kernel , rnayak@codeaurora.org, Shiraz Hashim , linux-arm-kernel Message-ID: <20170630121236.dqbya3gh5r5mi5xk@sirena.org.uk> References: <20170629144711.GO29665@vireshk-i7> <1522ae7b-fd5b-5403-62bf-b0140e116d65@gr13.net> <20170630031648.GR29665@vireshk-i7> <20170630035533.GV29665@vireshk-i7> <20170630041211.GX29665@vireshk-i7> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="tcpilgwxp6dosn7t" Content-Disposition: inline In-Reply-To: X-Cookie: 667: User-Agent: NeoMutt/20170609 (1.8.3) X-SA-Exim-Connect-IP: 176.12.107.140 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [RFC 0/5] drivers: Add boot constraints core X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: No (on mezzanine.sirena.org.uk); Unknown failure Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1658 Lines: 41 --tcpilgwxp6dosn7t Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jun 30, 2017 at 12:22:13PM +0800, Chen-Yu Tsai wrote: > What I'm saying is for the DT case, the constraints are already limited > to the intersection of all users, regardless of whether they are turned > on or not. At least this is what I believe makes sense. You really don't > want to set a regulator such that it over voltages for a subset of its > consumers. Consumers might not have proper power isolation for this. Right, and we also shouldn't have voltage setting code in consumers that don't need to vary their voltage at runtime. This keeps complexity out of drivers and avoids the need to handle things like variants that have different power requirements. > I think what you mean is that the DT constraints are the union of all > consumer constraints (1.8 - 3.0 V in this case), then each consumer > comes in and adds its own constraints. And for such a design, the kernel > needs to know which and what constraints to apply. That's the broad idea. --tcpilgwxp6dosn7t Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAllWQDMACgkQJNaLcl1U h9BUSAf/fdEdYhJsgdhG/zst7DxLL7b/3UxgV1sqs/W+7EzYTJmO3vraaYaSfYOT BVnZYkeLYb7ya/eSzbv8J3wDdsCqDvzZzb5XWUFARppSupmIoZj4Bh0woCRg7bUB SSqvdBXJn9/OjFNIw4VuOQT0hEWxHybSaWCJhdnKIhqmk44FZbjIPY72+tQEmzry NNuTatxgvV6erEsGN+uhSfgLRGdDiAa+hhwjKGnB55myE0QCJmk/pdKqo/UsrHVI qpsgzCU35UX3UwzaV+spcyX7z85Xi3lQ6HcljkWy4UZl7z165fKFzQDOkQk9SzKj /71q1dsFPjtwHRCdpMLHQNFTbtEoRQ== =qqBQ -----END PGP SIGNATURE----- --tcpilgwxp6dosn7t--