From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755448Ab0EUN2F (ORCPT ); Fri, 21 May 2010 09:28:05 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:59650 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753427Ab0EUN2D (ORCPT ); Fri, 21 May 2010 09:28:03 -0400 Date: Fri, 21 May 2010 14:34:32 +0100 From: Alan Cox To: David Brownell Cc: felipe.balbi@nokia.com, Mark Brown , Linux OMAP Mailing List , Linux Kernel Mailing List , Tony Lindgren , Andrew Morton Subject: Re: [PATCH 1/5] gpiolib: introduce set_debounce method Message-ID: <20100521143432.5de6ebec@lxorguk.ukuu.org.uk> In-Reply-To: <396934.73027.qm@web180307.mail.gq1.yahoo.com> References: <20100521111136.53dba6c9@lxorguk.ukuu.org.uk> <396934.73027.qm@web180307.mail.gq1.yahoo.com> X-Mailer: Claws Mail 3.7.5 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > One of the earlier examples of why to want debouncing (in the > original discussion, not this one) was for buttons (one signal > per button press) and the hardware designers don't necessarily > hook buttons up to only GPIOs with hardware debounce. So code > to kick in debounce there needed to be sensitive to whether or > not the capability was available ... and moreover, whether the > debounce scale was adequate to compensate the contact chatter. > When not, then software debounce was inescapable. And someone who needs it can contribute it. The proposed patch causes no problems in this area. Alan