From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: [PATCH] regulator: Provide dummy supply support Date: Wed, 2 Nov 2011 15:29:31 +0100 Message-ID: <20111102142931.GL23421@pengutronix.de> References: <1319833618-25190-1-git-send-email-s.hauer@pengutronix.de> <20111028215931.GA30366@opensource.wolfsonmicro.com> <20111028224757.GG23421@pengutronix.de> <201111011350.17425.vapier@gentoo.org> <20111101182720.GH10029@opensource.wolfsonmicro.com> <20111102100355.GJ23421@pengutronix.de> <20111102104126.GA2678@opensource.wolfsonmicro.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20111102104126.GA2678@opensource.wolfsonmicro.com> Sender: linux-kernel-owner@vger.kernel.org To: Mark Brown Cc: Mike Frysinger , linux-kernel@vger.kernel.org, Liam Girdwood , Linus Walleij , Paul Mundt , Tony Lindgren , linux-sh@vger.kernel.org, linux-omap@vger.kernel.org, uclinux-dist-devel@blackfin.uclinux.org List-Id: linux-omap@vger.kernel.org On Wed, Nov 02, 2011 at 10:41:27AM +0000, Mark Brown wrote: > On Wed, Nov 02, 2011 at 11:03:56AM +0100, Sascha Hauer wrote: > > On Tue, Nov 01, 2011 at 06:27:21PM +0000, Mark Brown wrote: > > > > As I think I said earlier I'd use the fixed regulator for this, all > > > Sascha's actually doing here is adding a wrapper to simplify > > > registration of that. > > > There's one difference between the fixed and the dummy regulator though: > > The fixed regulator has a voltage. The same dummy regulator instance can > > No, the voltage is optional. Ok, didn't know this. > > > be used for all devices which do not have a software controllable > > regulator. I think the same can be done with the fixed regulator aswell, > > but the bogus voltage showing up in the sysfs entry might be confusing > > to users. > > I don't think that's a meaningful issue, any in any case it'd be better > practice to fill it in so devices can use the information if they want > to (which really shouldn't be hard > > > Another approach to this topic would be to allow a board to explicitely > > bind to the existing dummy regulator, like the following (error path > > should of course be implemented before applying this) > > If you know you've got a fixed voltage supply I don't understand why you > wouldn't want to set one up. There clearly is an actual supply in the > system... It's just that it's simpler for a board to provide all dummy supplies in a single array, no matter if the real voltage is 1.8V or 3.3V. Anyway, as the voltage is optional in a fixed regulator this is no problem. I'll update my patch to use the fixed regulator then. 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 |