From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755644Ab0JEQQS (ORCPT ); Tue, 5 Oct 2010 12:16:18 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:49714 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755466Ab0JEQQQ (ORCPT ); Tue, 5 Oct 2010 12:16:16 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; b=nykcWSsHOEOAgUA7qpghGWdWPL53+8h6fk/9SsGOKohA6sVWK5CxQxxp1gNuM4/Plx iELWICt77A7zp9r9AEVEFPwI3Cg5BXL1Bjm8vENhzYM9ecKQ4gEinceOCc30ymjCMcjr O9mt2HljjRtS+TrHQVIcJb+BqJ9yyR5RSyZx8= Date: Tue, 5 Oct 2010 09:16:08 -0700 From: Dmitry Torokhov To: Igor Grinberg Cc: Mark Brown , Marek Vasut , linux-arm-kernel@lists.infradead.org, vapier@gentoo.org, khilman@deeprootsystems.com, linux-kernel@vger.kernel.org, pavel@ucw.cz, linux-input@vger.kernel.org, eric.y.miao@gmail.com, akpm@linux-foundation.org Subject: Re: [PATCH v2] Input: Make ADS7846 independent on regulator Message-ID: <20101005161608.GD19730@core.coreip.homeip.net> References: <1280560182-7071-1-git-send-email-marek.vasut@gmail.com> <4C862EB3.4080006@compulab.co.il> <20100907125335.GD25830@sirena.org.uk> <201009091027.18176.marek.vasut@gmail.com> <20100909094120.GB1988@rakim.wolfsonmicro.main> <4CAACA63.6090202@compulab.co.il> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4CAACA63.6090202@compulab.co.il> 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 On Tue, Oct 05, 2010 at 08:49:07AM +0200, Igor Grinberg wrote: > On 09/09/10 12:41, Mark Brown wrote: > > On Thu, Sep 09, 2010 at 10:27:17AM +0200, Marek Vasut wrote: > >> Dne Út 7. září 2010 14:53:35 Mark Brown napsal(a): > >>> From a regulator API usage point of view a separate implementation of > >>> the same thing was nacked - there are regulator API facilties for hiding > >>> missing regulators from drivers when needed to get systems going, unless > >>> the device genuinely can cope without supplies it should be relying on > >>> those. > > I actually, don't see why ads7846 is strictly relying on the regulator > and I don't understand, why ads7846 driver has to bail out if the regulator > is not found? Why shouldn't the driver try to continue? > I think it should bail out only in case communicating with the device failed. > > >> Maybe these platforms should have been fixed prior to applying the patch adding > >> regulator goo into ads7846 driver then. What's the way to go now then ? > > Fix the platforms and use the dummy regulators to keep them going until > > that happens. It's trivial to do the hookup in the platforms. > > You want each platform, that does not have a special regulated power supply > for the ads7846, to define a dummy regulator just to cope with that artificial > dependency of the device driver? > I think it is a waste and big code duplication in each platform > that does not have that special regulator. > I tend to agree, however I think that original patch that simply ignored failures from regulator_get() is not the best option either. Can we have a flag in platform data indicating that the board does not employ a regulator? Then we could retain the hard failure in cases when we expect regulator to be present while allowing to continue on boards that do not have it. -- Dmitry