From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@roeck-us.net (Guenter Roeck) Date: Sat, 4 Mar 2017 07:07:28 -0800 Subject: [PATCH 4/4] watchdog: sama5d4: Add comment explaining what happens on resume In-Reply-To: <20170302173114.28508-5-alexandre.belloni@free-electrons.com> References: <20170302173114.28508-1-alexandre.belloni@free-electrons.com> <20170302173114.28508-5-alexandre.belloni@free-electrons.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/02/2017 09:31 AM, Alexandre Belloni wrote: > Because suspending to RAM may lose the register values, they are restored > on resume. This is currently done unconditionally because there is > currently no way to know (from the driver) whether they have really been > lost or are still valid. Writing MR also pings the watchdog and this may > not be what is expected so add a comment explaining why it happens. > > Signed-off-by: Alexandre Belloni Reviewed-by: Guenter Roeck > --- > drivers/watchdog/sama5d4_wdt.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c > index d710014f3b7d..0ae947c3d7bc 100644 > --- a/drivers/watchdog/sama5d4_wdt.c > +++ b/drivers/watchdog/sama5d4_wdt.c > @@ -300,6 +300,11 @@ static int sama5d4_wdt_resume(struct device *dev) > { > struct sama5d4_wdt *wdt = dev_get_drvdata(dev); > > + /* > + * FIXME: writing MR also pings the watchdog which may not be desired. > + * This should only be done when the registers are lost on suspend but > + * there is no way to get this information right now. > + */ > sama5d4_wdt_init(wdt); > > return 0; >