From: Bartosz Golaszewski <brgl@kernel.org>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: "Bartosz Golaszewski" <bartosz.golaszewski@oss.qualcomm.com>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Daniel Scally" <djrscally@gmail.com>,
"Heikki Krogerus" <heikki.krogerus@linux.intel.com>,
"Sakari Ailus" <sakari.ailus@linux.intel.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Danilo Krummrich" <dakr@kernel.org>,
"Mika Westerberg" <mika.westerberg@linux.intel.com>,
"Andy Shevchenko" <andy@kernel.org>,
"Linus Walleij" <linusw@kernel.org>,
"Hans de Goede" <hansg@kernel.org>,
"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
"Len Brown" <lenb@kernel.org>,
linux-acpi@vger.kernel.org, driver-core@lists.linux.dev,
linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
platform-driver-x86@vger.kernel.org
Subject: Re: [PATCH v2 2/4] gpio: swnode: defer probe on references to unregistered software nodes
Date: Fri, 3 Apr 2026 09:26:41 +0200 [thread overview]
Message-ID: <CAMRc=Mda08=9zUuhaFVPYc368WE8Tz+Pc7ABCPoiQXWCBiBt9A@mail.gmail.com> (raw)
In-Reply-To: <ac7ZA6HJFBhyCROM@google.com>
On Thu, Apr 2, 2026 at 11:04 PM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> On Thu, Apr 02, 2026 at 02:54:27PM +0200, Bartosz Golaszewski wrote:
> > fwnode_property_get_reference_args() now returns -ENXIO when called on a
> > software node referencing another software node which has not yet been
> > registered as a firmware node. It makes sense to defer probe in this
> > situation as the node will most likely be registered later on and we'll
> > be able to resolve the reference eventually. Change the behavior of
> > swnode_find_gpio() to return -EPROBE_DEFER if the software node reference
> > resolution returns -ENXIO.
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
> > ---
> > drivers/gpio/gpiolib-swnode.c | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/gpio/gpiolib-swnode.c b/drivers/gpio/gpiolib-swnode.c
> > index 0d7f3f09a0b4bee0cf1bbdaa8b7b8ae4cd5de581..06d74e9e199de0b91a019e5e15d4b83d330291e7 100644
> > --- a/drivers/gpio/gpiolib-swnode.c
> > +++ b/drivers/gpio/gpiolib-swnode.c
> > @@ -95,6 +95,15 @@ struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode,
> > break;
> > }
> > if (ret) {
> > + if (ret == -ENXIO)
>
>
> I'll be just sitting here and quoting sashiko all day long ;)
>
I would love it to produce briefer messages. I'm always put off by the
walls of text. I would literally rather deal with neanderthal mode
like: "loop continues on ret != 0, bad!".
> "
> If swnode_gpio_get_reference() returns -ENXIO during the first iteration
> (for example, when checking the con_id-gpios suffix), won't the loop continue
> since the return value is not 0?
>
> Looking at the loop just above this block:
>
> for_each_gpio_property_name(propname, con_id) {
> ret = swnode_gpio_get_reference(fwnode, propname, idx, &args);
> if (ret == 0)
> break;
> }
>
> If the initial property check returns -ENXIO, but the subsequent fallback
> check for the con_id-gpio suffix returns -ENOENT, the ret variable gets
> overwritten.
>
> When the loop terminates, ret would be -ENOENT instead of -ENXIO. Could this
> cause the probe deferral check to evaluate to false and fail the probe
> entirely instead of deferring it as intended?
>
> Should the loop also break early if -ENXIO is encountered?
>
> "
>
> You need to change that to
>
> if (ret == 0 || ret == -ENXIO)
> break;
>
> because if we get -ENXIO that means the GPIO must be there (the property
> exists) but not ready yet and we do not want to fall back to another
> suffix.
>
Yes, thanks.
Bart
next prev parent reply other threads:[~2026-04-03 7:26 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-02 12:54 [PATCH v2 0/4] platform/x86: x86-android-tablets: use real firmware node references with intel drivers Bartosz Golaszewski
2026-04-02 12:54 ` [PATCH v2 1/4] software node: return -ENXIO when referenced swnode is not registered yet Bartosz Golaszewski
2026-04-02 13:35 ` Andy Shevchenko
2026-04-02 20:43 ` Dmitry Torokhov
2026-04-03 7:29 ` Bartosz Golaszewski
2026-04-03 18:07 ` Dmitry Torokhov
2026-04-07 10:57 ` Bartosz Golaszewski
2026-04-07 13:30 ` Bartosz Golaszewski
2026-04-07 13:59 ` Andy Shevchenko
2026-04-02 12:54 ` [PATCH v2 2/4] gpio: swnode: defer probe on references to unregistered software nodes Bartosz Golaszewski
2026-04-02 21:04 ` Dmitry Torokhov
2026-04-03 7:26 ` Bartosz Golaszewski [this message]
2026-04-03 13:44 ` Bartosz Golaszewski
2026-04-02 12:54 ` [PATCH v2 3/4] ACPI: bus: export the acpi_bus_type symbol Bartosz Golaszewski
2026-04-02 12:54 ` [PATCH v2 4/4] platform/x86: x86-android-tablets: enable fwnode matching of GPIO chips Bartosz Golaszewski
2026-04-04 18:25 ` Rafael J. Wysocki
2026-04-27 11:30 ` Bartosz Golaszewski
2026-04-02 13:23 ` [PATCH v2 0/4] platform/x86: x86-android-tablets: use real firmware node references with intel drivers Andy Shevchenko
2026-04-02 13:35 ` Bartosz Golaszewski
2026-04-02 13:47 ` Andy Shevchenko
2026-04-02 15:03 ` Bartosz Golaszewski
2026-04-02 16:05 ` Andy Shevchenko
2026-04-02 16:13 ` Bartosz Golaszewski
2026-04-02 16:18 ` Andy Shevchenko
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