Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033942AbbKFWC4 (ORCPT ); Fri, 6 Nov 2015 17:02:56 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:42170 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030298AbbKFWCy (ORCPT ); Fri, 6 Nov 2015 17:02:54 -0500 Date: Fri, 6 Nov 2015 14:02:49 -0800 From: Guenter Roeck To: Tim Harvey Cc: Akshay Bhat , linux-watchdog@vger.kernel.org, Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Wim Van Sebroeck , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Shawn Guo , Sascha Hauer , Russell King - ARM Linux , "linux-arm-kernel@lists.infradead.org" , justin.waters@timesys.com, Lucas Stach , Fabio Estevam , Stefan Roese Subject: Re: [PATCH v4 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop Message-ID: <20151106220249.GA19791@roeck-us.net> References: <1446758362-11702-1-git-send-email-akshay.bhat@timesys.com> <1446758362-11702-2-git-send-email-akshay.bhat@timesys.com> <20151105222325.GA26159@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3200 Lines: 65 On Fri, Nov 06, 2015 at 11:53:42AM -0800, Tim Harvey wrote: > On Thu, Nov 5, 2015 at 2:23 PM, Guenter Roeck wrote: > > On Thu, Nov 05, 2015 at 04:19:21PM -0500, Akshay Bhat wrote: > >> From: Tim Harvey > >> > >> The IMX6 watchdog supports assertion of a signal (WDOG_B) which > >> can be pinmux'd to an external pin. This is typically used for boards that > >> have PMIC's in control of the IMX6 power rails. In fact, failure to use > >> such an external reset on boards with external PMIC's can result in various > >> hangs due to the IMX6 not being fully reset [1] as well as the board failing > >> to reset because its PMIC has not been reset to provide adequate voltage for > >> the CPU when coming out of reset at 800Mhz. > >> > >> This uses a new device-tree property 'ext-reset-output' to indicate the > >> board has such a reset and to cause the watchdog to be configured to assert > >> WDOG_B instead of an internal reset both on a watchdog timeout and in > >> system_restart. > >> > >> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/333689.html > >> > >> Cc: Lucas Stach > >> Signed-off-by: Tim Harvey > >> --- > >> .../devicetree/bindings/watchdog/fsl-imx-wdt.txt | 2 ++ > >> drivers/watchdog/imx2_wdt.c | 20 ++++++++++++++++++-- > >> 2 files changed, 20 insertions(+), 2 deletions(-) > >> > >> diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > >> index 8dab6fd..9b89b3a 100644 > >> --- a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > >> +++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt > >> @@ -9,6 +9,8 @@ Optional property: > > > > properties ? > > > >> - big-endian: If present the watchdog device's registers are implemented > >> in big endian mode, otherwise in native mode(same with CPU), for more > >> detail please see: Documentation/devicetree/bindings/regmap/regmap.txt. > >> +- ext-reset-output: If present the watchdog device is configured to assert its > > > > Should that have a vendor prefix ? Also, not sure if "-output" > > has any real value in the property name. "fsl,external-reset", maybe ? > > Hi Guenter, > > I don't see why a vendor prefix is necessary - its a feature of the > IMX6 watchdog supported by this driver to be able to trigger an > internal chip-level reset and/or an external signal that can be hooked > to additional hardware. > Sounded like vendor specific to me, but then I am not a devicetree maintainer, so I am not an authority on the subject. > I started with ext-reset, but it was suggested > (http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/347437.html) > to also make it clear that this is an 'output' and not a reset input. > No problem, as long as you get an Ack from a devicetree maintainer. Guenter -- 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/