From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:41873 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752479Ab1FGJ7h (ORCPT ); Tue, 7 Jun 2011 05:59:37 -0400 Received: by wwa36 with SMTP id 36so4739894wwa.1 for ; Tue, 07 Jun 2011 02:59:36 -0700 (PDT) Date: Tue, 7 Jun 2011 10:59:32 +0100 From: Jamie Iles To: Florian Fainelli Cc: Wim Van Sebroeck , linux-mips@linux-mips.org, linux-watchdog@vger.kernel.org, Manuel Lauss , stable@kernel.org Subject: Re: [PATCH 3/3] WATCHDOG: mtx1-wdt: fix GPIO toggling Message-ID: <20110607095932.GC21174@pulham.picochip.com> References: <201106021454.21827.florian@openwrt.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201106021454.21827.florian@openwrt.org> Sender: linux-watchdog-owner@vger.kernel.org List-Id: linux-watchdog@vger.kernel.org On Thu, Jun 02, 2011 at 02:54:21PM +0200, Florian Fainelli wrote: > Commit e391be76 (MIPS: Alchemy: Clean up GPIO registers and accessors) > changed the way the GPIO was toggled. Prior to this patch, we would > always actively drive the GPIO output to either 0 or 1, this patch > drove the GPIO active to 0, and put the GPIO in tristate to drive it > to 1, unfortunately this does not work, revert back to active driving. > > Using a signed variable (gstate) to hold the gpio state and using a bit- > wise operation on it also resulted in toggling value from 1 to -2 since > the variable is signed. This value was then passed on to gpio_direction_ > output, which always perform a if (value) ... to set the value to the > gpio, so we were always writing a 1 to this GPIO instead of 1 -> 0 -> 1 ... > > CC: stable@kernel.org > Signed-off-by: Florian Fainelli > --- > diff --git a/drivers/watchdog/mtx-1_wdt.c b/drivers/watchdog/mtx-1_wdt.c > index 16086f8..9756da9 100644 > --- a/drivers/watchdog/mtx-1_wdt.c > +++ b/drivers/watchdog/mtx-1_wdt.c > @@ -66,7 +66,7 @@ static struct { > int default_ticks; > unsigned long inuse; > unsigned gpio; > - int gstate; > + unsigned int gstate; > } mtx1_wdt_device; > > static void mtx1_wdt_trigger(unsigned long unused) > @@ -78,11 +78,8 @@ static void mtx1_wdt_trigger(unsigned long unused) > ticks--; > > /* toggle wdt gpio */ > - mtx1_wdt_device.gstate = ~mtx1_wdt_device.gstate; > - if (mtx1_wdt_device.gstate) > - gpio_direction_output(mtx1_wdt_device.gpio, 1); > - else > - gpio_direction_input(mtx1_wdt_device.gpio); > + mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate; > + gpio_direction_output(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate); Would gpio_set_value() be more appropriate here? Isn't the gpio always an output after the first call? Jamie