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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Thu, 20 Jan 2022 12:12:58 +0200
Message-ID: <CAHp75VfVJo=8FPX_Pw15X5B3awFXpuEq+=LryxB6M4Ub-YJ7uA@mail.gmail.com>
Subject: Re: [PATCH v2 3/3] i2c: smbus: Use device_*() functions instead of of_*()
To:     Akhil R <akhilrajeev@nvidia.com>
Cc:     Christian Koenig <christian.koenig@amd.com>,
        Dmitry Osipenko <digetx@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Laxman Dewangan <ldewangan@nvidia.com>,
        linux-i2c <linux-i2c@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-tegra <linux-tegra@vger.kernel.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Wolfram Sang <wsa@kernel.org>, Len Brown <lenb@kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>
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On Thu, Jan 20, 2022 at 11:48 AM Akhil R <akhilrajeev@nvidia.com> wrote:
> > On Wed, Jan 12, 2022 at 4:15 PM Akhil R <akhilrajeev@nvidia.com> wrote:

...

> > This change reveals potential issue:
> >
> > > -               irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert");
> > > +               irq = device_irq_get_byname(adapter->dev.parent, "smbus_alert");
> >
> > >                 if (irq <= 0)
> >
> > I guess this '= 0' part should be fixed first.
>
> '0' is a failure as per the documentation of of_irq_get_byname() as well as
> of_irq_get(). The case is different for acpi_irq_get(), but it is handled in
> fwnode_irq_get(). If I understood it right, a return value of '0' should be
> considered a failure here.

Depends. I have no idea what the original code does here. But
returning an error or 0 from this function seems confusing to me.


-- 
With Best Regards,
Andy Shevchenko