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Date: Fri, 17 Feb 2017 16:16:50 +0100 From: Alexandre Belloni <alexandre.belloni@...e-electrons.com> To: Guenter Roeck <linux@...ck-us.net> Cc: Wim Van Sebroeck <wim@...ana.be>, Nicolas Ferre <nicolas.ferre@...el.com>, linux-watchdog@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v2 2/3] watchdog: sama5d4: Fix setting timeout when watchdog is disabled On 17/02/2017 at 06:40:33 -0800, Guenter Roeck wrote: > On 02/16/2017 11:30 AM, Alexandre Belloni wrote: > > The datasheet states: "When setting the WDDIS bit, and while it is set, the > > fields WDV and WDD must not be modified." > > > > Ensure WDDIS is not set when changing the timeout and set it afterwards if > > the watchdog was disabled. > > > > Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com> > > --- > > Changes in v2: > > - new patch > > drivers/watchdog/sama5d4_wdt.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c > > index 2c6f5a70ae67..2a60251806d2 100644 > > --- a/drivers/watchdog/sama5d4_wdt.c > > +++ b/drivers/watchdog/sama5d4_wdt.c > > @@ -90,11 +90,18 @@ static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd, > > u32 reg; > > > > reg = wdt_read(wdt, AT91_WDT_MR); > > + > > + if (reg & AT91_WDT_WDDIS) > > + wdt_write(wdt, AT91_WDT_MR, reg & ~AT91_WDT_WDDIS); > > + > > reg &= ~AT91_WDT_WDV; > > reg &= ~AT91_WDT_WDD; > > reg |= AT91_WDT_SET_WDV(value); > > reg |= AT91_WDT_SET_WDD(value); > > - wdt_write(wdt, AT91_WDT_MR, reg); > > + wdt_write(wdt, AT91_WDT_MR, reg & ~AT91_WDT_WDDIS); > > + > > + if (reg & AT91_WDT_WDDIS) > > + wdt_write(wdt, AT91_WDT_MR, reg); > > > That means if the watchdog is running, the timeout would not be updated. > It should be updated no matter if it is running or not. > No, it is enabling the watchdog, then changing WDV and WDD and finally disabling the watchdog if necessary. So, WDV and WDD are always changed. -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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