Re: [RFC PATCH 1/3] dt-bindings: gpio-rcar: Add optional use-alternative-interrupt property

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Marek Vasut <marek.vasut+renesas@gmail.com>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Chris Paterson <chris.paterson2@renesas.com>,
	Yusuke Ashiduka <ashiduka@fujitsu.com>,
	Torii Kenichi <torii.ken1@jp.fujitsu.com>,
	Fukui Yohhei <yohhei.fukui@denso-ten.com>,
	Yasushi Asano <yasano@jp.adit-jv.com>,
	Yuichi Kusakabe <yuichi.kusakabe@denso-ten.com>,
	Andrew Gabbasov <andrew_gabbasov@mentor.com>,
	Jiada Wang <jiada_wang@mentor.com>,
	Eugeniu Rosca <rosca.eugeniu@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>
Subject: Re: [RFC PATCH 1/3] dt-bindings: gpio-rcar: Add optional use-alternative-interrupt property
Date: Fri, 24 Apr 2020 10:06:59 +0200	[thread overview]
Message-ID: <CAMuHMdXvrBHuBpVbJ=fUcRsQ9qk4Q3Lr13DeJjiHanN3f8K+1g@mail.gmail.com> (raw)
In-Reply-To: <20200422101026.9220-2-erosca@de.adit-jv.com>

Hi Eugeniu,

CC devicetree

On Wed, Apr 22, 2020 at 12:11 PM Eugeniu Rosca <erosca@de.adit-jv.com> wrote:
> From: Torii Kenichi <torii.ken1@jp.fujitsu.com>
>
> When setting this property, you must set alternate interrupt number in
> the 'interrupts' property.
>
> Signed-off-by: Torii Kenichi <torii.ken1@jp.fujitsu.com>
> [erosca: tidy up the descriptions/comments]
> Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>

Thanks for your/forwarding this patch!

> --- a/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt
> +++ b/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt
> @@ -50,6 +50,9 @@ Optional properties:
>    - clocks: Must contain a reference to the functional clock.  The property is
>      mandatory if the hardware implements a controllable functional clock for
>      the GPIO instance.
> +  - use-alternative-interrupt: Use 'alternative' GPIO interrupt instead

renesas,use-alternative-interrupt?
(unless you can convince Rob this becomes a generic property).

> +    of 'normal' GPIO interrupt. When you specify this property, you must
> +    also change the 'interrupts' DT property.

In light of "DT describes the hardware", I think you should instead list
both interrupts in DT.  I.e. first/single interrupt is the normal one,
second optional interrupt is the alternative one.

On R-Car Gen2, the oldest SoC family with this feature I could find,
they are called "ext_int" resp. "ext_alt_int", so introducing the
optional "clock-names" property would be a good idea, too.

>    - gpio-reserved-ranges: See gpio.txt.

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