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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 16 Aug 2021 15:48:28 +0300
Message-ID: <CAHp75VdC8GFmV-uOHPQpv5q=q0ZwSKFXW6gOL-hK6N4_qS1YJw@mail.gmail.com>
Subject: Re: [PATCH v6 3/5] iio: adc: ad7949: add vref selection support
To:     Liam Beguin <liambeguin@gmail.com>
Cc:     Lars-Peter Clausen <lars@metafoo.de>,
        Michael Hennerich <Michael.Hennerich@analog.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Charles-Antoine Couret <charles-antoine.couret@essensium.com>,
        =?UTF-8?B?TnVubyBTw6E=?= <Nuno.Sa@analog.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>
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On Mon, Aug 16, 2021 at 3:39 PM Liam Beguin <liambeguin@gmail.com> wrote:
> On Mon Aug 16, 2021 at 4:04 AM EDT, Andy Shevchenko wrote:
> > On Mon, Aug 16, 2021 at 12:35 AM Liam Beguin <liambeguin@gmail.com>
> > wrote:

...

> > > +       tmp = 4096000;
> > > +       ret = device_property_read_u32(dev, "adi,internal-ref-microvolt", &tmp);
> >
> > > +       if (ret < 0 && ret != -EINVAL) {
>
> Hi Andy,
>
> >
> > What does this check (second part) is supposed to mean?
> > The first part will make it mandatory, is it the goal?
> >
>
> device_property_read_u32() will return -EINVAL if the property isn't
> found in the devicetree.
>
> This checks for errors when the property is defined while keeping it
> optional.

Don't assign and don't check the error code of the API. As simply as that.

> > > +               dev_err(dev, "invalid value for adi,internal-ref-microvolt\n");
> > > +               return ret;
> > > +       }


-- 
With Best Regards,
Andy Shevchenko