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From: David Lechner <dlechner@baylibre.com>
Date: Mon, 25 Mar 2024 08:35:16 -0500
Message-ID: <CAMknhBHZT5xM5RG0cmEHvCJ5AwZnLQnV9_jW5=gP=s_45LYfcw@mail.gmail.com>
Subject: Re: [PATCH 2/2] iio: adc: Add support for AD4000
To: Marcelo Schmitt <marcelo.schmitt@analog.com>
Cc: lars@metafoo.de, Michael.Hennerich@analog.com, jic23@kernel.org, 
	robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, 
	marcelo.schmitt1@gmail.com, linux-iio@vger.kernel.org, 
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
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On Sat, Mar 23, 2024 at 4:53=E2=80=AFPM David Lechner <dlechner@baylibre.co=
m> wrote:
>
> On Fri, Mar 22, 2024 at 5:06=E2=80=AFPM Marcelo Schmitt
> <marcelo.schmitt@analog.com> wrote:
> >

..

> > +
> > +       vref_reg =3D devm_regulator_get(&spi->dev, "vref");
>
> This should to be devm_regulator_get_optional(), otherwise it can
> return a "dummy" regulator if one is missing in the devicetree which
> will fail when getting the voltage.
>
> > +       if (IS_ERR(vref_reg))
> > +               return dev_err_probe(&spi->dev, PTR_ERR(vref_reg),
> > +                                    "Failed to get vref regulator\n");
> > +
> > +       ret =3D regulator_enable(vref_reg);
> > +       if (ret < 0)
> > +               return dev_err_probe(&spi->dev, ret,
> > +                                    "Failed to enable voltage regulato=
r\n");
> > +
> > +       ret =3D devm_add_action_or_reset(&spi->dev, ad4000_regulator_di=
sable, vref_reg);
> > +       if (ret)
> > +               return dev_err_probe(&spi->dev, ret,
> > +                                    "Failed to add regulator disable a=
ction\n");
> > +
> > +       st->vref =3D regulator_get_voltage(vref_reg);
> > +       if (st->vref < 0)
> > +               return dev_err_probe(&spi->dev, st->vref, "Failed to ge=
t vref\n");
> > +
> > +       if (!device_property_present(&spi->dev, "adi,spi-cs-mode")) {
> > +               st->cnv_gpio =3D devm_gpiod_get(&spi->dev, "cnv", GPIOD=
_OUT_HIGH);
> > +               if (IS_ERR(st->cnv_gpio)) {
> > +                       if (PTR_ERR(st->cnv_gpio) =3D=3D -EPROBE_DEFER)
> > +                               return -EPROBE_DEFER;
> > +
> > +                       return dev_err_probe(&spi->dev, PTR_ERR(st->cnv=
_gpio),
> > +                                            "Failed to get CNV GPIO");
> > +               }
> > +       }
>

In a review for a different patch, Jonathan said he would prefer
devm_regulator_get() and failing in regulator_get_voltage() rather
than using devm_regulator_get_optional() so I think the same would
apply here and my suggestion should be overruled.