From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752361Ab3LETkJ (ORCPT ); Thu, 5 Dec 2013 14:40:09 -0500 Received: from 10.mo4.mail-out.ovh.net ([188.165.33.109]:53683 "EHLO mo4.mail-out.ovh.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750723Ab3LETkG (ORCPT ); Thu, 5 Dec 2013 14:40:06 -0500 X-Greylist: delayed 4199 seconds by postgrey-1.27 at vger.kernel.org; Thu, 05 Dec 2013 14:40:06 EST Message-ID: <52A0AEB4.7090909@bracey.fi> Date: Thu, 05 Dec 2013 18:49:56 +0200 From: Kevin Bracey User-Agent: Mozilla/5.0 (Windows NT 6.0; WOW64; rv:17.0) Gecko/20130215 Thunderbird/17.0.3 MIME-Version: 1.0 To: Tomasz Figa CC: Mark Brown , Linus Walleij , Kyungmin Park , "devicetree@vger.kernel.org" , linux-samsung-soc , =?ISO-8859-1?Q?Heiko_St=FCbner?= , Stephen Warren , Doug Anderson , "linux-kernel@vger.kernel.org" , Kukjin Kim , Thomas Abraham , "linux-arm-kernel@lists.infradead.org" , Marek Szyprowski Subject: Re: [PATCH] pinctrl: samsung: Allow pin value to be initialized using pinfunc. References: <1384881351-10782-1-git-send-email-t.figa@samsung.com> <20131205150747.GW29268@sirena.org.uk> <1502243.eRBlCfUhTO@amdc1227> In-Reply-To: <1502243.eRBlCfUhTO@amdc1227> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Ovh-Tracer-Id: 12704654549761495205 X-Ovh-Remote: 62.183.157.30 (62-183-157-30.bb.dnainternet.fi) X-Ovh-Local: 213.186.33.20 (ns0.ovh.net) X-OVH-SPAMSTATE: OK X-OVH-SPAMSCORE: -100 X-OVH-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeiledrkeejucetufdoteggodetrfcurfhrohhfihhlvgemucfqggfjnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd X-Spam-Check: DONE|U 0.5/N X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeiledrkeejucetufdoteggodetrfcurfhrohhfihhlvgemucfqggfjnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/12/2013 17:11, Tomasz Figa wrote: > On Thursday 05 of December 2013 15:07:47 Mark Brown wrote: >> On Tue, Dec 03, 2013 at 10:29:42AM +0100, Linus Walleij wrote: >> >>> So a suggested patch to support weak hogs would be interesting >>> to look at. Can you provide details on how you think this would >>> work? >> Or should we be going and applying the default state to all devices on >> init without worrying about a driver appearing? > If a device isn't used, then it's often better to configure the pins for > a different function, such as GPIO, to minimize leakage current. > And there can also be mutually-exclusive drivers choosing different default states for the same pin. I think you do need a separate "safe" indicator. My current thought is that a late-init "make safe all unclaimed pins" pass would make sense - you can't really mess with pins in an automated fashion on init, as it can mess up bootloader->driver handover. There already exist late-init "turn off all unclaimed clocks" (at least on shmobile) and "turn off all unclaimed regulators", and it would fit that model. Kevin