RE: [PATCH v9 3/9] watchdog: rzg2l_wdt: Use pm_runtime_resume_and_get()

[Biju Das]

> Subject: RE: [PATCH v9 3/9] watchdog: rzg2l_wdt: Use pm_runtime_resume_and_get()
> 
> Hi Claudiu,
> 
> > -----Original Message-----
> > From: Claudiu <claudiu.beznea@xxxxxxxxx>
> > Sent: Friday, May 31, 2024 7:57 AM
> > Subject: [PATCH v9 3/9] watchdog: rzg2l_wdt: Use
> > pm_runtime_resume_and_get()
> >
> > From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> >
> > pm_runtime_get_sync() may return with error. In case it returns with
> > error
> > dev->power.usage_count needs to be decremented.
> > dev->pm_runtime_resume_and_get()
> > takes care of this. Thus use it.
> >
> > Along with it the rzg2l_wdt_set_timeout() function was updated to
> > propagate the result of
> > rzg2l_wdt_start() to its caller.
> >
> > Fixes: 2cbc5cd0b55f ("watchdog: Add Watchdog Timer driver for RZ/G2L")
> > Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> > Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
> >
> > Changes in v9:
> > - collected Guenter's Rb tag
> >
> > Changes in v8:
> > - none
> >
> > Changes in v7:
> > - none
> >
> > Changes in v6:
> > - none
> >
> > Changes in v5:
> > - none
> >
> > Changes in v4:
> > - none
> >
> > Changes in v3:
> > - none
> >
> > Changes in v2:
> > - propagate the return code of rzg2l_wdt_start() to it's callers
> >
> >
> >  drivers/watchdog/rzg2l_wdt.c | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/watchdog/rzg2l_wdt.c
> > b/drivers/watchdog/rzg2l_wdt.c index 1741f98ca67c..d87d4f50180c 100644
> > --- a/drivers/watchdog/rzg2l_wdt.c
> > +++ b/drivers/watchdog/rzg2l_wdt.c
> > @@ -123,8 +123,11 @@ static void rzg2l_wdt_init_timeout(struct
> > watchdog_device *wdev)  static int rzg2l_wdt_start(struct watchdog_device *wdev)  {
> >  	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
> > +	int ret;
> >
> > -	pm_runtime_get_sync(wdev->parent);
> > +	ret = pm_runtime_resume_and_get(wdev->parent);
> > +	if (ret)
> > +		return ret;
> 
> Checking ret will lead to imbalance. It should be ret < 0 as ret = 1 corresponds to RPM_ACTIVE and
> the API does not call put() when ret = 1; see [1] and [2]
> 
> [1] https://elixir.bootlin.com/linux/v6.10-rc6/source/drivers/base/power/runtime.c#L778
> 
> [2] https://elixir.bootlin.com/linux/v6.10-rc6/source/include/linux/pm_runtime.h#L431

Please ignore me. Sorry for the noise.

the code for pm_runtime_resume_and_get() seems to be correct.
https://elixir.bootlin.com/linux/latest/source/include/linux/pm_runtime.h#L436

Cheers,
Biju