From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90F47C4346E for ; Thu, 24 Sep 2020 07:47:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 527192376F for ; Thu, 24 Sep 2020 07:47:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727199AbgIXHrT (ORCPT ); Thu, 24 Sep 2020 03:47:19 -0400 Received: from relay5-d.mail.gandi.net ([217.70.183.197]:37665 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727120AbgIXHrT (ORCPT ); Thu, 24 Sep 2020 03:47:19 -0400 X-Greylist: delayed 79346 seconds by postgrey-1.27 at vger.kernel.org; Thu, 24 Sep 2020 03:47:18 EDT X-Originating-IP: 90.65.88.165 Received: from localhost (lfbn-lyo-1-1908-165.w90-65.abo.wanadoo.fr [90.65.88.165]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay5-d.mail.gandi.net (Postfix) with ESMTPSA id 29F031C000F; Thu, 24 Sep 2020 07:47:15 +0000 (UTC) Date: Thu, 24 Sep 2020 09:47:15 +0200 From: Alexandre Belloni To: Qiang Zhao , Bruno Thomsen Cc: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Wim Van Sebroeck , Guenter Roeck , "linux-watchdog@vger.kernel.org" , "a.zummo@towertech.it" , "robh+dt@kernel.org" , "linux-rtc@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "kernel@pengutronix.de" Subject: Re: [Patch v2 1/3] dt-bindings: rtc: pcf2127: Add bindings for nxp,pcf2127 Message-ID: <20200924074715.GT9675@piout.net> References: <20200921054821.26071-1-qiang.zhao@nxp.com> <20200923094449.GP9675@piout.net> <20200924070456.rovgp6n5q25s53vc@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Hi, On 24/09/2020 07:23:18+0000, Qiang Zhao wrote: > > > Yes, you are right, There is not a fundamental solution. > > > However it somewhat avoid this situation at least. > > > > > > And if without this issue, > > > is it correct to register a rtc device as watchdog no matter it is used as > > watchdog on the board? > > > Every time Linux are booted up, watchdog device should be configured to the > > right one manually. > > > So the patch are useful, even though it is not for the issue. > > > > > > What should we do to really resolve this issue? > > > > I still think we need a kernel solution here. I would expect that most assembled > > pcf2127 chips are unable to act as a watchdog (i.e. don't have the RST output > > connected to something that resets the machine). > > > > So my favoured solution would be a positive property like: > > > > has-watchdog; > > > > or something similar. In my eyes this is definitely something we want to specify > > in the device tree because it is a relevant hardware property. > > I consider it a bug to give a watchdog device to userspace that isn't functional. > > > > Best regards > > Uwe > > I strongly agree with you! It should be positive property. > However, we couldn't identify which board are using pcf2127 as watchdog, > So we are unable to modify the boards' dts to correct (watchdog or not) in this patchset. > > I noticed that only LS series platforms and imx6 have pcf2127 node, as far as I know, the LS platforms don't use it as watchdog, > But I am not sure about imx6 > I don't think there is any user upstream and it is recent engouh that we can probably make that a positive property. Bruno, is it ok for you? you are the only know user of the feature. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com