From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@free-electrons.com (Boris Brezillon) Date: Tue, 19 May 2015 11:14:02 +0200 Subject: at91sam9: watchdog: period In-Reply-To: <555AFBFD.3010506@aksignal.cz> References: <55559D55.6020703@aksignal.cz> <20150515172516.005e3a21@bbrezillon> <5559865F.9010502@aksignal.cz> <20150518092750.449d6c8c@bbrezillon> <5559A029.9060007@aksignal.cz> <555AA8F1.80100@atmel.com> <20150519091442.675b1a98@bbrezillon> <555AFBFD.3010506@aksignal.cz> Message-ID: <20150519111402.747e8eb2@bbrezillon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 19 May 2015 11:01:49 +0200 Ji?? Prchal wrote: > > > On 19.5.2015 09:14, Boris Brezillon wrote: > > On Tue, 19 May 2015 11:07:29 +0800 > > "Yang, Wenyou" wrote: > > > >> > >> > >> On 2015/5/18 16:17, Ji?? Prchal wrote: > >>> > >>> > >>> On 18.5.2015 09:27, Boris Brezillon wrote: > >>>> > >>>> Can you dump watchdog registers (using devmem) ? > >>> > >>> / # devmem 0xfffffe40 > >>> 0x00000000 > >>> / # devmem 0xfffffe44 > >>> 0x1FFF2FFF > >>> / # devmem 0xfffffe48 > >>> 0x00000000 > >>> > >> The register value is right. > > > > It seems correct to me too. > > > Not to me, I want 4s: > [ 4.675675] at91sam9_wdt: enabled (heartbeat=4 sec, nowayout=1) There's a difference between your heartbeat (the frequency you refresh/reset your watchdog) and the watchdog expiration time (here set to 16 secs). We usually set the heartbeat to 1/2 or 1/4 the expiration time, so that we're (almost) sure we can reset the watchdog before its expiration. -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com