Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753842AbaLAOIt (ORCPT ); Mon, 1 Dec 2014 09:08:49 -0500 Received: from mail-ie0-f172.google.com ([209.85.223.172]:61095 "EHLO mail-ie0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753585AbaLAOIq (ORCPT ); Mon, 1 Dec 2014 09:08:46 -0500 MIME-Version: 1.0 In-Reply-To: <547C4A26.3070108@nod.at> References: <547B4464.9090300@nod.at> <547C4A26.3070108@nod.at> Date: Mon, 1 Dec 2014 15:08:45 +0100 Message-ID: Subject: Re: iio: dht11 broken From: Linus Walleij To: Richard Weinberger Cc: Harald Geyer , "linux-gpio@vger.kernel.org" , Javier Martinez Canillas , Alexandre Courbot , Stephen Warren , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald , "linux-iio@vger.kernel.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 1, 2014 at 11:59 AM, Richard Weinberger wrote: > Am 01.12.2014 um 11:49 schrieb Harald Geyer: >> Any input from gpiolib people about what the proper fix would be in >> their opinion, of course is appreciated. I don't think the dht11 driver >> is doing anything unreasonable per se, so maybe they can clarify how >> the API is intended to be used? > > Your driver sets up a GPIO as IRQ and then you switch the mode to output > to enable the DHT sensor. > This is not an API issue, it is an design issue. > I'm not a hardware expert but AFAIK setting an IRQ pin into output mode can > lead to undefined behavior. Well that check is there exactly to prevent madness like this. IRQs on pins set to output *does* *not* *make* *sense*. Remove the IRQ before setting the pin to output and vice versa and everyone will be happier. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/