From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH 0/5] MMC: mmci: Provide bindings for Device Tree Date: Sat, 17 Mar 2012 21:26:53 +0000 Message-ID: <20120317212652.GD3315@opensource.wolfsonmicro.com> References: <1331734803-17954-1-git-send-email-lee.jones@linaro.org> <201203152058.31398.arnd@arndb.de> <201203161236.36088.arnd@arndb.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="UoPmpPX/dBe4BELn" Return-path: Received: from opensource.wolfsonmicro.com ([80.75.67.52]:43795 "EHLO opensource.wolfsonmicro.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754921Ab2CQV05 (ORCPT ); Sat, 17 Mar 2012 17:26:57 -0400 Content-Disposition: inline In-Reply-To: <201203161236.36088.arnd@arndb.de> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Arnd Bergmann Cc: Linus Walleij , Per Forlin , niklas.hernaeus@linaro.org, linux-mmc@vger.kernel.org, cjb@laptop.org, Lee Jones , linux-arm-kernel@lists.infradead.org --UoPmpPX/dBe4BELn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Mar 16, 2012 at 12:36:35PM +0000, Arnd Bergmann wrote: > On Friday 16 March 2012, Linus Walleij wrote: > > On Thu, Mar 15, 2012 at 9:58 PM, Arnd Bergmann wrote: > > But I guess you're after modelling the levelshifter as a regulator? > > Basically the level shifter is a separate device has two voltage > > inputs A and B (from other regulators) that is controlled by a > > simple GPIO to select voltage A or B to drive the signals to > > the card. > > That could probably be modelled as a regulator with two > > volategs for sure, but then we should maybe create a more > > generic "struct level_shifter_regulator" (or whatever) for the > > concept as a whole. > Ok, thanks for the explanation. I'm not sure I'd bother defining a special regulator type for this if it is done using regulators - given that it's likely to just be a GPIO rather than a specific driver I'm not sure it's worth worrying about how exactly the hardware is implemented. > > Let's page Mark about what to do with levelshifters and whether > > they are regulators of sorts in his book. > It does sound appealing, especially because this one could be > done completely generically by defining a regulator that has > a bunch of other regulators as well as a set of gpio lines as > inputs and one output that can be used in other devices. We > would probably only use this one together with device tree then. It seems sensible to me - probably the existing gpio-regulator driver can do the job, though it's not unreasonable to expect that we'll want to support switching between variable voltage supplies at some point. --UoPmpPX/dBe4BELn Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJPZQFnAAoJEBus8iNuMP3dH2QP/jlFcGcMlmij+7XS83YKRo8S rUr+JzLCXXhwG1qUZMIBykH5zu7uLZeHHClrworViHOu3jewk/DV+9Z+WHjdWjvy Pf8K21xJxEaaREkAA8dyYy8jvCX8FrtherqNgoPFMfltAFPzO9YyVe9bKEUNpsNJ ZEs52uU9wuaWbfhg4pN0sAhL9smH3owRxqfubWkJe1uQg1hPk1VX8v55ggO8kdiB FG0w6E7cgrTJkXCF3bIaqazPIj5UCP37rYU49gOi4Nsy9Nl4/SQvufJt2x0DJDoC a6T+Ucmj0kKIM1PUKFNbEAxcCk2qq8NndRqWfPZRv24a4PJJMPgYkZ4pLvQNEjHQ DZqLE7/GyzKwgHzHIvZzBuJGFW7qLBbioziUipsHPhRSYWbwQ8fzkJCTyC8lZh5R n5thwrMyWzveECbLsO04dXYYgHd0vjltdo07vz1IAl6upUNPdUUsZzVJEkNnZFZe v/65alEkwhXHLQnIVqYe8HP6tD4ijcdUDqMcqiSdFcCssDjAd1+yndUvL2Zg0FY1 gTsX6ksdKpI59BvYXcC9a34uIeRq61ReVM2UZefaMS+/klE2bWte5K7eaZrkV63s ssLxtOug6bsOdFs9dqxhmyszWKsF9cUvOklu5yYb7qeQfN2ppn00vgGnIIG/VpbN Morrawkbo11id15sKSAh =gFnw -----END PGP SIGNATURE----- --UoPmpPX/dBe4BELn--