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From:   Saravana Kannan <saravanak@google.com>
Date:   Tue, 5 Jul 2022 19:24:39 -0700
Message-ID: <CAGETcx-WBOJEANsf+bopmEu-MTsOGiijmFU4UZn-A0bcUCTSTg@mail.gmail.com>
Subject: Re: [PATCH 1/2] usb: gadget: udc: atmel: check rc of devm_gpiod_get_optional()
To:     Michael Walle <michael@walle.cc>
Cc:     Cristian Birsan <cristian.birsan@microchip.com>,
        Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Claudiu Beznea <claudiu.beznea@microchip.com>,
        linux-arm-kernel@lists.infradead.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Tue, Jul 5, 2022 at 1:56 PM Michael Walle <michael@walle.cc> wrote:
>
> Am 2022-07-05 20:53, schrieb Saravana Kannan:
> > On Tue, Jul 5, 2022 at 6:19 AM Michael Walle <michael@walle.cc> wrote:
> >>
> >> devm_gpiod_get_optional() might still return an error code, esp.
> >> EPROBE_DEFER. Return any errors.
> >>
> >> Signed-off-by: Michael Walle <michael@walle.cc>
> >> ---
> >>  drivers/usb/gadget/udc/atmel_usba_udc.c | 2 ++
> >>  1 file changed, 2 insertions(+)
> >>
> >> diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c
> >> b/drivers/usb/gadget/udc/atmel_usba_udc.c
> >> index ae2bfbac603e..48355e0cee76 100644
> >> --- a/drivers/usb/gadget/udc/atmel_usba_udc.c
> >> +++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
> >> @@ -2165,6 +2165,8 @@ static struct usba_ep * atmel_udc_of_init(struct
> >> platform_device *pdev,
> >>
> >>         udc->vbus_pin = devm_gpiod_get_optional(&pdev->dev,
> >> "atmel,vbus",
> >>                                                 GPIOD_IN);
> >> +       if (IS_ERR(udc->vbus_pin))
> >> +               return ERR_CAST(udc->vbus_pin);
> >
> > I'm confused. Is it really an optional resource if you treat a failure
> > to get it
> > as a reason to fail a probe?
>
> If the gpio isn't found NULL is returned.

Ah, ok.

-Saravana