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Date: Fri, 17 Feb 2017 06:47:03 -0800 From: Guenter Roeck <linux@...ck-us.net> To: Alexandre Belloni <alexandre.belloni@...e-electrons.com> 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 3/3] watchdog: sama5d4: Implement resume hook 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@...e-electrons.com> > --- > 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 ? > + 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 ? > + if (wdt->mr & AT91_WDT_WDDIS) > + wdt_write(wdt, AT91_WDT_MR, wdt->mr); > + > + return 0; > +} > +#endif > + > +static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops, sama5d4_wdt_suspend, > + sama5d4_wdt_resume); > + > static struct platform_driver sama5d4_wdt_driver = { > .probe = sama5d4_wdt_probe, > .remove = sama5d4_wdt_remove, > .driver = { > .name = "sama5d4_wdt", > + .pm = &sama5d4_wdt_pm_ops, > .of_match_table = sama5d4_wdt_of_match, > } > }; >
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