From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris brezillon Subject: Re: [RFC PATCH] gpio: add GPIO hogging mechanism Date: Thu, 19 Dec 2013 18:18:40 +0100 Message-ID: <52B32A70.1080700@overkiz.com> References: <1387463671-1164-1-git-send-email-b.brezillon@overkiz.com> <1387463671-1164-2-git-send-email-b.brezillon@overkiz.com> <20131219164109.GB27409@kroah.com> <20131219164737.GA4536@saruman.home> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from 2.mo3.mail-out.ovh.net ([46.105.75.36]:40066 "EHLO mo3.mail-out.ovh.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753704Ab3LSRTN (ORCPT ); Thu, 19 Dec 2013 12:19:13 -0500 Received: from mail408.ha.ovh.net (b6.ovh.net [213.186.33.56]) by mo3.mail-out.ovh.net (Postfix) with SMTP id F160CFF9BC6 for ; Thu, 19 Dec 2013 18:19:11 +0100 (CET) In-Reply-To: <20131219164737.GA4536@saruman.home> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: balbi@ti.com, Greg Kroah-Hartman Cc: Rob Landley , Linus Walleij , Alexandre Courbot , Jiri Prchal , Ben Gamari , Mark Rutland , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, devicetree@vger.kernel.org Hello Felipe, On 19/12/2013 17:47, Felipe Balbi wrote: > On Thu, Dec 19, 2013 at 08:41:09AM -0800, Greg Kroah-Hartman wrote: >> On Thu, Dec 19, 2013 at 03:34:31PM +0100, Boris BREZILLON wrote: >>> GPIO hogging is a way to request and configure specific GPIO without >>> explicitly requesting it in the device driver. >>> >>> The request and configuration procedure is handled in the core device >>> driver code before the driver probe function is called. >>> >>> It allows specific GPIOs to be configured without any driver specific code. >>> >>> Particularly usefull when a external device is connected to a bus and the >>> bus connections depends on an external switch controlled by a GPIO pin. > for external switches, you probably need a pinctrl-gpio driver. > Do you mean using pinctrl pinconf to configure the PIN as output-high or output-low ? This was my first proposal (see https://www.mail-archive.com/devicetree@vger.kernel.org/msg05829.html). Best Regards, Boris