On 17/02/2017 at 06:47:03 -0800, Guenter Roeck wrote:
> On 02/16/2017 11:30 AM, Alexandre Belloni wrote:
> > When resuming for the deepest state on sama5d2, it is necessary to restore
> > MR as the registers are lost.
> >
> > Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
> > ---
> > Changes in v2:
> > - cache mr beofre suspending
> >
> > drivers/watchdog/sama5d4_wdt.c | 32 ++++++++++++++++++++++++++++++++
> > 1 file changed, 32 insertions(+)
> >
> > diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
> > index 2a60251806d2..5ddeb4803dc3 100644
> > --- a/drivers/watchdog/sama5d4_wdt.c
> > +++ b/drivers/watchdog/sama5d4_wdt.c
> > @@ -28,6 +28,7 @@
> > struct sama5d4_wdt {
> > struct watchdog_device wdd;
> > void __iomem *reg_base;
> > + u32 mr;
>
> Makes me wonder if we shouldn't just retain the original 'config'
> (and maybe rename it to 'mr). After all, it _is_ used now.
>
> > };
> >
> > static int wdt_timeout = WDT_DEFAULT_TIMEOUT;
> > @@ -248,11 +249,42 @@ static const struct of_device_id sama5d4_wdt_of_match[] = {
> > };
> > MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
> >
> > +#ifdef CONFIG_PM_SLEEP
> > +static int sama5d4_wdt_suspend(struct device *dev)
> > +{
> > + struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
> > +
> > + wdt->mr = wdt_read(wdt, AT91_WDT_MR);
> > +
>
> Wouldn't you want to stop the watchdog here if it is running,
> ie set AT91_WDT_WDDIS ?
>
Some existing customers want the watchdog to continue to run while the
system is suspended.
> > + return 0;
> > +}
> > +
> > +static int sama5d4_wdt_resume(struct device *dev)
> > +{
> > + struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
> > + u32 reg;
> > +
> > + reg = wdt_read(wdt, AT91_WDT_MR);
> > + if (reg & AT91_WDT_WDDIS)
> > + wdt_write(wdt, AT91_WDT_MR, reg & ~AT91_WDT_WDDIS);
> > +
> > + wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS);
>
> Is that necessary ? Why not just write wdt->mr unconditionally ?
>
Because you can change WDV and WDD *OR* WDDIS but not both at the same
time.
--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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