[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <Yxc8s8IfzElm/mjS@smile.fi.intel.com>
Date: Tue, 6 Sep 2022 15:27:31 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Thierry Reding <thierry.reding@...il.com>,
Mark Brown <broonie@...nel.org>,
Matti Vaittinen <mazziesaccount@...il.com>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Claudiu Beznea <claudiu.beznea@...rochip.com>,
Liam Girdwood <lgirdwood@...il.com>,
Wim Van Sebroeck <wim@...ux-watchdog.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Miquel Raynal <miquel.raynal@...tlin.com>,
Linus Walleij <linus.walleij@...aro.org>,
Felipe Balbi <balbi@...nel.org>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Krzysztof Wilczyński <kw@...ux.com>,
Vignesh Raghavendra <vigneshr@...com>,
Daniel Vetter <daniel@...ll.ch>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Alexandre Torgue <alexandre.torgue@...s.st.com>,
Marc Zyngier <maz@...nel.org>,
Richard Weinberger <richard@....at>,
David Airlie <airlied@...ux.ie>,
Nicolas Ferre <nicolas.ferre@...rochip.com>,
Alyssa Rosenzweig <alyssa@...enzweig.io>,
Bartosz Golaszewski <brgl@...ev.pl>,
Jonathan Hunter <jonathanh@...dia.com>,
Rob Herring <robh@...nel.org>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Pali Rohár <pali@...nel.org>,
LINUXWATCHDOG <linux-watchdog@...r.kernel.org>,
USB <linux-usb@...r.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
linux-pci <linux-pci@...r.kernel.org>,
linux-tegra <linux-tegra@...r.kernel.org>,
"open list:MEMORY TECHNOLOGY..." <linux-mtd@...ts.infradead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
dri-devel <dri-devel@...ts.freedesktop.org>,
linux-stm32@...md-mailman.stormreply.com,
linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using
devm_gpiod_get()
On Mon, Sep 05, 2022 at 03:07:48PM -0700, Guenter Roeck wrote:
> On 9/5/22 12:55, Andy Shevchenko wrote:
> > On Mon, Sep 5, 2022 at 10:51 PM Dmitry Torokhov
> > <dmitry.torokhov@...il.com> wrote:
> > > 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@...il.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@...il.com> wrote:
...
> > > > > > > + 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 has to do with a dead code. If defm_gpiod_get() does not return
> > NULL, then why do we even bother to check?
>
> PTR_ERR_OR_ZERO() converts into an error code (if the pointer is an
> ERR_PTR) or 0 if it is a real pointer. Its purpose is not to convert
> NULL into 0, its purpose is to convert a pointer either into an error
> code or 0. That is what is done here, and it is done all over the place
> in the kernel. I don't see your problem with it. Care to explain ?
>
> > > 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).
> >
> > I don't see how this is relevant.
>
> You lost me. Really, please explain your problem with PTR_ERR_OR_ZERO().
I don't know what I was thinking about... You, guys, are right, sorry for
my noise.
--
With Best Regards,
Andy Shevchenko
Powered by blists - more mailing lists