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Date:   Mon, 5 Sep 2022 12:51:39 -0700
From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
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Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using
 devm_gpiod_get()
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On Mon, Sep 05, 2022 at 10:41:40PM +0300, Andy Shevchenko wrote:
> On Mon, Sep 5, 2022 at 10:40 PM Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> > On Mon, Sep 05, 2022 at 01:59:44PM +0300, Andy Shevchenko wrote:
> > > On Mon, Sep 5, 2022 at 9:32 AM Dmitry Torokhov
> > > <dmitry.torokhov@gmail.com> wrote:
> 
> ...
> 
> > > > -               gpiod = devm_gpiod_get_from_of_node(&pdev->dev, np,
> > > > -                                                   "nvidia,phy-reset-gpio",
> > > > -                                                   0, GPIOD_OUT_HIGH,
> > > > -                                                   "ulpi_phy_reset_b");
> > > > +               gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
> > > > +                                      GPIOD_OUT_HIGH);
> > > >                 err = PTR_ERR_OR_ZERO(gpiod);
> > >
> > > What does _OR_ZERO mean now?
> >
> > This converts a pointer to an error code if a pointer represents
> > ERR_PTR() encoded error, or 0 to indicate success.
> 
> Yes, I know that. My point is, how is it useful now (or even before)?
> I mean that devm_gpio_get() never returns NULL, right?

What does returning NULL have to do with anything. It converts a pointer
to a "classic" return code, with negative errors and 0 on success.

It allows to not use multiple IS_ERR/PTR_ERR in the code (I'd need 1
IS_ERR and 2 PTR_ERR, one in dev_err() and another to return).

Thanks.

-- 
Dmitry