From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757569AbZBLCQy (ORCPT ); Wed, 11 Feb 2009 21:16:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755656AbZBLCQo (ORCPT ); Wed, 11 Feb 2009 21:16:44 -0500 Received: from smtp128.sbc.mail.sp1.yahoo.com ([69.147.65.187]:39028 "HELO smtp128.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754976AbZBLCQn (ORCPT ); Wed, 11 Feb 2009 21:16:43 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=yQKQgw47snu05EZr560rABznX7EVJHZe3z6MSgJuVnahT3zKUiJ10DoK35yM+ZE1/LZz8JPx4ADFcGaozAuDVBYveK3v/SPxs2n1O0jYiJQ/WMFH5DGSuCVj3QvVcZl141C4rai0v66f9v1TjthoSuhMRp92nBfu1UQRmxRz5gg= ; X-YMail-OSG: KVtXez0VM1nDdA0DRG7TXQshvdBc8dL5.dRFGmL.1hvQitthsRWhFH8lolvJ2ZY.RGC2KNR6YYctMJaXJRICF32j5zGqFYMrkB1Fvo75Hj8nQHNk3H0f.tNvoop0TB58hMW_rJ5jp49H.CbGni6lLOWP X-Yahoo-Newman-Property: ymail-3 From: David Brownell To: Joonyoung Shim Subject: Re: [PATCH] twl4030-gpio: Fix getting the value of the TWL4030 GPIO output pin Date: Wed, 11 Feb 2009 18:16:41 -0800 User-Agent: KMail/1.9.10 Cc: Tony Lindgren , linux-arm-kernel@lists.arm.linux.org.uk, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org References: <4e1455be0902062213o769a4d15ha0c892508839dbad@mail.gmail.com> <200902070000.49089.david-b@pacbell.net> <4e1455be0902090502l554ca462m9c096e359a5b29c3@mail.gmail.com> In-Reply-To: <4e1455be0902090502l554ca462m9c096e359a5b29c3@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Content-Disposition: inline Message-Id: <200902111816.41569.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 09 February 2009, Joonyoung Shim wrote: > but, it doesn't return actual value of the pin if twl4030 GPIO pin is output. So it would seem that these GPIOs don't support bidirectional usage. Documentation/gpio.txt includes: >>> However, note that not all platforms can >>> read the value of output pins; those that can't >>> should always return zero. Which is exactly what's happening here, it seems... > For example, the GPIO13 pin of twl4030 is configured as an output > using gpio_direction_output() and assigns the GPIO's value to 1 > using gpio_set_value_cansleep(), the result of "# cat /sys/kernel/debug/gpio" > reports to me as follows. > > GPIOs 192-209, platform/twl4030_gpio, twl4030, can sleep: >  gpio-205 (keyled              ) out lo > > but it should have reported "hi" instead of "lo". >