From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757715AbaKTRXw (ORCPT ); Thu, 20 Nov 2014 12:23:52 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:55115 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757470AbaKTRXr (ORCPT ); Thu, 20 Nov 2014 12:23:47 -0500 Date: Thu, 20 Nov 2014 09:23:29 -0800 From: Guenter Roeck To: Mike Looijmans Cc: wim@iguana.be, linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] gpio_wdt: Add "always_running" feature to GPIO watchdog Message-ID: <20141120172329.GA10673@roeck-us.net> References: <1416489377-13633-1-git-send-email-mike.looijmans@topic.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1416489377-13633-1-git-send-email-mike.looijmans@topic.nl> User-Agent: Mutt/1.5.21 (2010-09-15) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-CTCH-PVer: 0000001 X-CTCH-Spam: Unknown X-CTCH-VOD: Unknown X-CTCH-Flags: 0 X-CTCH-RefID: str=0001.0A020205.546E23A2.02C2,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-CTCH-Score: 0.001 X-CTCH-ScoreCust: 0.000 X-CTCH-Rules: C_4847, X-CTCH-SenderID: linux@roeck-us.net X-CTCH-SenderID-Flags: 0 X-CTCH-SenderID-TotalMessages: 8 X-CTCH-SenderID-TotalSpam: 0 X-CTCH-SenderID-TotalSuspected: 0 X-CTCH-SenderID-TotalConfirmed: 0 X-CTCH-SenderID-TotalBulk: 0 X-CTCH-SenderID-TotalVirus: 0 X-CTCH-SenderID-TotalRecipients: 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: mailgid no entry from get_relayhosts_entry 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 On Thu, Nov 20, 2014 at 02:16:17PM +0100, Mike Looijmans wrote: > On some chips, like the TPS386000, the trigger cannot be disabled > and the CPU must keep toggling the line at all times. Add a switch > "always_running" to keep toggling the GPIO line regardless of the > state of the soft part of the watchdog. The "armed" member keeps > track of whether a timeout must also cause a reset. > > Signed-off-by: Mike Looijmans > --- > drivers/watchdog/gpio_wdt.c | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c > index 220a9e0..921ee67 100644 > --- a/drivers/watchdog/gpio_wdt.c > +++ b/drivers/watchdog/gpio_wdt.c > @@ -31,6 +31,8 @@ struct gpio_wdt_priv { > int gpio; > bool active_low; > bool state; > + bool always_running; > + bool armed; > unsigned int hw_algo; > unsigned int hw_margin; > unsigned long last_jiffies; > @@ -56,6 +58,7 @@ static int gpio_wdt_start(struct watchdog_device *wdd) > gpio_direction_output(priv->gpio, priv->state); > priv->last_jiffies = jiffies; > mod_timer(&priv->timer, priv->last_jiffies + priv->hw_margin); > + priv->armed = true; > > return 0; > } > @@ -64,8 +67,11 @@ static int gpio_wdt_stop(struct watchdog_device *wdd) > { > struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); > > - mod_timer(&priv->timer, 0); > - gpio_wdt_disable(priv); > + priv->armed = false; > + if (!priv->always_running) { > + mod_timer(&priv->timer, 0); > + gpio_wdt_disable(priv); > + } > > return 0; > } > @@ -91,7 +97,7 @@ static void gpio_wdt_hwping(unsigned long data) > struct watchdog_device *wdd = (struct watchdog_device *)data; > struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); > > - if (time_after(jiffies, priv->last_jiffies + > + if (priv->armed && time_after(jiffies, priv->last_jiffies + > msecs_to_jiffies(wdd->timeout * 1000))) { > dev_crit(wdd->dev, "Timer expired. System will reboot soon!\n"); > return; > @@ -197,6 +203,9 @@ static int gpio_wdt_probe(struct platform_device *pdev) > /* Use safe value (1/2 of real timeout) */ > priv->hw_margin = msecs_to_jiffies(hw_margin / 2); > > + priv->always_running = of_property_read_bool(pdev->dev.of_node, > + "always_running"); That will need to be documented in a devicetree bindings document, and be reviewed by the fdt maintainers. I may be wrong, but I think devicetree properties commonly use '-', not '_'. Guenter > + > watchdog_set_drvdata(&priv->wdd, priv); > > priv->wdd.info = &gpio_wdt_ident; > @@ -218,6 +227,11 @@ static int gpio_wdt_probe(struct platform_device *pdev) > if (ret) > watchdog_unregister_device(&priv->wdd); > > + if (priv->always_running) { > + gpio_wdt_start(&priv->wdd); > + priv->armed = false; > + } > + > return ret; > } > > -- > 1.7.9.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html