linux-kernel - Re: [PATCH v1 1/3] gpio: defer probe if pinctrl cannot be found

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Date:	Thu, 2 Jul 2015 10:49:27 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Tomeu Vizoso <tomeu.vizoso@...labora.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	linux-tegra@...r.kernel.org,
	Linus Walleij <linus.walleij@...aro.org>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	Alexandre Courbot <gnurou@...il.com>
Subject: Re: [PATCH v1 1/3] gpio: defer probe if pinctrl cannot be found

Hi Tomeu,

On Wed, Jul 1, 2015 at 2:45 PM, Tomeu Vizoso <tomeu.vizoso@...labora.com> wrote:
> When an OF node has a pin range for its GPIOs, return -EPROBE_DEFER if
> the pin controller isn't available.
>
> Otherwise, the GPIO range wouldn't be set at all unless the pin
> controller probed always before the GPIO chip.
>
> With this change, the probe of the GPIO chip will be deferred and will
> be retried at a later point, hopefully once the pin controller has been
> registered and probed already.
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>

I was a bit afraid this would break the case of gpio controllers that are
also pin controllers, i.e. where "gpio-ranges" points to the gpio controller
itself[*], but it doesn't.

Tested-by: Geert Uytterhoeven <geert+renesas@...der.be>

[*] E.g. "[PATCH 2/7] ARM: shmobile: r8a7740 dtsi: Add missing "gpio-ranges"
    to gpio node" (http://www.spinics.net/lists/linux-sh/msg43077.html)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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
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