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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Harish Jenny K N <harish_kandiga@mentor.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
	Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Eugeniu Rosca <erosca@de.adit-jv.com>,
	Alexander Graf <graf@amazon.com>,
	Peter Maydell <peter.maydell@linaro.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Phil Reid <preid@electromag.com.au>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Magnus Damm <magnus.damm@gmail.com>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [PATCH v3 5/7] gpio: Add GPIO Aggregator/Repeater driver
Date: Tue, 3 Dec 2019 09:17:58 +0100
Message-ID: <CAMuHMdW-n8ao7t7156WYxRg7v8+ojXsRgHGUOax=9nBo2F5xOw@mail.gmail.com> (raw)
In-Reply-To: <585c4ad9-31fc-e87e-07c4-b8d6aa09c7e4@mentor.com>

Hi Harish,

On Tue, Dec 3, 2019 at 6:42 AM Harish Jenny K N
<harish_kandiga@mentor.com> wrote:
> > +static int gpio_aggregator_probe(struct platform_device *pdev)
> > +{
> > +     struct device *dev = &pdev->dev;
> > +     struct gpio_desc **descs;
> > +     struct gpiochip_fwd *fwd;
> > +     int i, n;
> > +
> > +     n = gpiod_count(dev, NULL);
> > +     if (n < 0)
> > +             return n;
> > +
> > +     descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL);
> > +     if (!descs)
> > +             return -ENOMEM;
> > +
> > +     for (i = 0; i < n; i++) {
> > +             descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
>
> can you please add this check as well as we need to return EPROBE_DEFER.
>
> if (desc[i] == ERR_PTR(-ENOENT))
> <                 return -EPROBE_DEFER;

So gpiod_get_index() nevers return -EPROBE_DEFER, but returns -ENOENT
instead?
How can a driver distinguish between "GPIO not found" and "gpiochip driver
not yet initialized"?
Worse, so the *_optional() variants will return NULL in both cases, too, so
the caller will always fall back to optional GPIO not present?

Or am I missing something?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

  reply index

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-27  8:42 [PATCH v3 0/7] gpio: Add GPIO Aggregator/Repeater Geert Uytterhoeven
2019-11-27  8:42 ` [PATCH v3 1/7] gpiolib: Add GPIOCHIP_NAME definition Geert Uytterhoeven
2019-11-28  3:38   ` Ulrich Hecht
2019-12-02 21:17   ` Eugeniu Rosca
2019-12-12 10:37   ` Linus Walleij
2019-11-27  8:42 ` [PATCH v3 2/7] gpiolib: Add support for gpiochipN-based table lookup Geert Uytterhoeven
2019-11-28  3:38   ` Ulrich Hecht
2019-12-12 13:20   ` Linus Walleij
2019-12-12 13:33     ` Geert Uytterhoeven
2019-12-12 14:36       ` Linus Walleij
2019-11-27  8:42 ` [PATCH v3 3/7] gpiolib: Add support for GPIO line " Geert Uytterhoeven
2019-11-28  3:39   ` Ulrich Hecht
2019-12-12 13:40   ` Linus Walleij
2019-11-27  8:42 ` [PATCH v3 4/7] dt-bindings: gpio: Add gpio-repeater bindings Geert Uytterhoeven
2019-11-28  3:39   ` Ulrich Hecht
2019-12-03  5:51   ` Harish Jenny K N
2019-12-05 21:06   ` Rob Herring
2019-12-06  9:17     ` Geert Uytterhoeven
2019-12-06 15:03       ` Rob Herring
2020-01-06  8:12         ` Geert Uytterhoeven
2020-01-07  9:22           ` Harish Jenny K N
2020-01-16  5:09             ` Harish Jenny K N
2019-11-27  8:42 ` [PATCH v3 5/7] gpio: Add GPIO Aggregator/Repeater driver Geert Uytterhoeven
2019-11-27 14:15   ` Eugeniu Rosca
2019-11-27 14:33     ` Geert Uytterhoeven
2019-11-28  3:40   ` Ulrich Hecht
2019-12-03  5:42   ` Harish Jenny K N
2019-12-03  8:17     ` Geert Uytterhoeven [this message]
2019-12-03  8:51       ` Harish Jenny K N
2019-12-03 10:51   ` Eugeniu Rosca
2020-01-09 13:35     ` Geert Uytterhoeven
2020-01-09 13:49       ` Eugeniu Rosca
2019-12-12 14:34   ` Linus Walleij
2019-12-12 15:24     ` Geert Uytterhoeven
2020-01-04  0:38       ` Linus Walleij
2020-01-06  8:23         ` Geert Uytterhoeven
2020-01-08 23:12           ` Linus Walleij
2019-11-27  8:42 ` [PATCH v3 6/7] docs: gpio: Add GPIO Aggregator/Repeater documentation Geert Uytterhoeven
2019-11-28  3:41   ` Ulrich Hecht
2019-12-12 14:42   ` Linus Walleij
2019-12-12 14:48     ` Geert Uytterhoeven
2020-01-04  0:21       ` Linus Walleij
2020-01-06  8:06         ` Geert Uytterhoeven
2019-11-27  8:42 ` [PATCH v3 7/7] MAINTAINERS: Add GPIO Aggregator/Repeater section Geert Uytterhoeven
2019-12-03  5:38   ` Harish Jenny K N
2020-01-18  1:46 ` [PATCH v3 0/7] gpio: Add GPIO Aggregator/Repeater Eugeniu Rosca
2020-01-20  9:33   ` Geert Uytterhoeven
2020-01-20 12:14     ` Eugeniu Rosca

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