From mboxrd@z Thu Jan 1 00:00:00 1970 From: alexandre.belloni@free-electrons.com (Alexandre Belloni) Date: Fri, 17 Feb 2017 16:16:50 +0100 Subject: [PATCH v2 2/3] watchdog: sama5d4: Fix setting timeout when watchdog is disabled In-Reply-To: <968ef53e-c3c4-5322-020a-8382ce367931@roeck-us.net> References: <20170216193053.5546-1-alexandre.belloni@free-electrons.com> <20170216193053.5546-2-alexandre.belloni@free-electrons.com> <968ef53e-c3c4-5322-020a-8382ce367931@roeck-us.net> Message-ID: <20170217151625.hv2vn5imx2kyeftt@piout.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > > --- > > 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