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[209.132.180.67]) by mx.google.com with ESMTP id a84si10488551pfk.72.2018.01.20.08.06.41; Sat, 20 Jan 2018 08:06:56 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=CDPjCU2I; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756278AbeATQEo (ORCPT + 99 others); Sat, 20 Jan 2018 11:04:44 -0500 Received: from mail-it0-f67.google.com ([209.85.214.67]:39036 "EHLO mail-it0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754301AbeATQEg (ORCPT ); Sat, 20 Jan 2018 11:04:36 -0500 Received: by mail-it0-f67.google.com with SMTP id 68so5371283ite.4; Sat, 20 Jan 2018 08:04:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=zJomkRSHQ/MoTEtJIp4qzYBQvn8e9JSDKqzCp+EdC3k=; b=CDPjCU2IGu2vfjYVH75V0mFWgIlKaoQBhaNEJp3gzqcsigaMr53/PY4Eiq/De49WHv gM2EADJM3+WTdfXr8qzMHPGSZ+h13m7TV2rdwHNGmpN6Y82D+RWri1ZcKs/D2ovRyudm zoT6SFJT8bbxELb/Q6yRfsnonHsZJ0M5ym3pgjVWOmZD62asSMpWghYnh5cN3l1qbLVu Tks3kWtT1GilQt4pr8p6GQzGDinOjNk7tXWVAg/Bw8MIsmpKQkr/ZbRc4tXFNpDgJJkS lit3MZWS1e+wMM4vzQzZFQo9y5KMdpPShUw2JgZ//IeYVcSbXdjs5b0RpOpNRasRaf5M 75DA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=zJomkRSHQ/MoTEtJIp4qzYBQvn8e9JSDKqzCp+EdC3k=; b=iYvZKyEdWWbbGHEGA+Mgf/OOV/6uis/sBxWBKLuWKwdT2BrgnVGGqUSZWoAuE/nZA+ nVJ0oeH4eyYe8IElfoKSVsMhAZ8FIKRQT9QL1BFULvIiD+E9X6Wbzx9duGcPQlaT5R3p 6OJqN44VU2wBqAOiRMKURaBwoxMUXk2nqC2QDyQpjmFT+5gyS/lceLsrE7iiLIVKU20Z eVYFpn0CUNLVAfkgtxF9AMyGtlGaHmkEa115yGxTZvACSuIXnncDjZYsosTlgA+157C8 rVDiw/WNip4sYn6CmNEnTattFjxVKWlK+z1bytOhZdNOztaCkOFQt8X+/FIzjNRIfErX 6Ckw== X-Gm-Message-State: AKwxyte18fQiTvWjY8uzHZOWKjiS7XMIAzWlHyERpvqM3M2kblI/7NT/ xXgmzaIZxmmdF7jMOPBnZCTFUr2CM+uUD33PvjA= X-Received: by 10.36.31.5 with SMTP id d5mr2152081itd.136.1516464275650; Sat, 20 Jan 2018 08:04:35 -0800 (PST) MIME-Version: 1.0 Received: by 10.2.165.9 with HTTP; Sat, 20 Jan 2018 08:04:35 -0800 (PST) In-Reply-To: <20061de8-fa1f-93eb-eb9b-089c699018aa@roeck-us.net> References: <20171228162939.3928-2-paul@crapouillou.net> <20171230135108.6834-1-paul@crapouillou.net> <20171230135108.6834-3-paul@crapouillou.net> <20061de8-fa1f-93eb-eb9b-089c699018aa@roeck-us.net> From: PrasannaKumar Muralidharan Date: Sat, 20 Jan 2018 21:34:35 +0530 Message-ID: Subject: Re: [PATCH v2 3/8] watchdog: JZ4740: Register a restart handler To: Guenter Roeck Cc: Paul Cercueil , Ralf Baechle , Rob Herring , Mark Rutland , Wim Van Sebroeck , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Linux-MIPS , open list , linux-watchdog@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Guenter, On 20 January 2018 at 21:15, Guenter Roeck wrote: > On 01/19/2018 11:31 PM, PrasannaKumar Muralidharan wrote: >> >> Hi Paul, >> >> On 30 December 2017 at 19:21, Paul Cercueil wrote: >>> >>> The watchdog driver can restart the system by simply configuring the >>> hardware for a timeout of 0 seconds. >>> >>> Signed-off-by: Paul Cercueil >>> Reviewed-by: Guenter Roeck >>> --- >>> drivers/watchdog/jz4740_wdt.c | 9 +++++++++ >>> 1 file changed, 9 insertions(+) >>> >>> v2: No change >>> >>> diff --git a/drivers/watchdog/jz4740_wdt.c >>> b/drivers/watchdog/jz4740_wdt.c >>> index 92d6ca8ceb49..fa7f49a3212c 100644 >>> --- a/drivers/watchdog/jz4740_wdt.c >>> +++ b/drivers/watchdog/jz4740_wdt.c >>> @@ -130,6 +130,14 @@ static int jz4740_wdt_stop(struct watchdog_device >>> *wdt_dev) >>> return 0; >>> } >>> >>> +static int jz4740_wdt_restart(struct watchdog_device *wdt_dev, >>> + unsigned long action, void *data) >>> +{ >>> + wdt_dev->timeout = 0; >>> + jz4740_wdt_start(wdt_dev); >>> + return 0; >>> +} >>> + >>> static const struct watchdog_info jz4740_wdt_info = { >>> .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | >>> WDIOF_MAGICCLOSE, >>> .identity = "jz4740 Watchdog", >>> @@ -141,6 +149,7 @@ static const struct watchdog_ops jz4740_wdt_ops = { >>> .stop = jz4740_wdt_stop, >>> .ping = jz4740_wdt_ping, >>> .set_timeout = jz4740_wdt_set_timeout, >>> + .restart = jz4740_wdt_restart, >>> }; >>> >>> #ifdef CONFIG_OF >>> -- >>> 2.11.0 >>> >>> >> >> Noticed that min_timeout of the watchdog device is set to 1 but this >> function calls start with timeout set to 0. Even though this works I >> feel it is better to set min_timeout to 0. >> > > No. That would be wrong. If you want to be pedantic, write a new function > __jz4740_wdt_set_timeout(u16 clock_div, u16 timeout_value) and call it > instead, but don't mess with min_timeout. > > Guenter What is the effect of changing min_timeout? I could see only validation checks with it. Thanks, PrasannaKumar