From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751999AbbJLLnE (ORCPT ); Mon, 12 Oct 2015 07:43:04 -0400 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:59752 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751255AbbJLLnB (ORCPT ); Mon, 12 Oct 2015 07:43:01 -0400 Date: Mon, 12 Oct 2015 13:42:59 +0200 From: Sascha Hauer To: Mark Brown Cc: linux-kernel@vger.kernel.org, Liam Girdwood , kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 4/6] regulator: core: Propagate voltage changes to supply regulators Message-ID: <20151012114259.GU7858@pengutronix.de> References: <1443621946-8712-1-git-send-email-s.hauer@pengutronix.de> <1443621946-8712-5-git-send-email-s.hauer@pengutronix.de> <20151002173256.GZ12635@sirena.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151002173256.GZ12635@sirena.org.uk> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 13:24:27 up 23 days, 53 min, 79 users, load average: 0.00, 0.08, 0.12 User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, On Fri, Oct 02, 2015 at 06:32:56PM +0100, Mark Brown wrote: > On Wed, Sep 30, 2015 at 04:05:44PM +0200, Sascha Hauer wrote: > > > A new min_dropout_uv field is added to struct regulator_desc. Regulators > > can specify the minimun dropout voltage they need for proper function > > here. Now when the voltage is changed on a regulator the regulator core > > makes sure that > > Can we have this interface addition as a separate patch please? Makes > it easier to add to other devices. I could've sworn I'd already done > that bit but obviously never got the patch mailed out. > > One change I think we need here is only doing the propagation if either > the device lacks a set_voltage() operation (in which case it's just a > switch passing through the parent voltage) Does the lack of a set_voltage() operation automatically mean it's a switch passing through the parent voltage? What if the regulator is a fixed regulator and the output can't be controlled because there is only one voltage? Currently we bail out int regulator_set_voltage() when we do not have a set_voltage() or set_voltage_sel() operation. Instead of propagating the voltage change up I would keep the current behaviour and implement voltage propagation for switches when we need it. Then we could also introduce a REGULATOR_IS_SWITCH flag indicating that this is a switch and not a fixed voltage regulator. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |