From: Linus Walleij <linus.walleij@linaro.org>
To: Chris Brandt <Chris.Brandt@renesas.com>
Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Russell King <linux@armlinux.org.uk>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 3/7] arm: dts: dt-bindings: Add Renesas RZ pinctrl header
Date: Thu, 30 Mar 2017 10:15:05 +0200 [thread overview]
Message-ID: <CACRpkda_Gw9vhLqpWw8oOZyZ59nj5j9Q-T5RXVsf0vsxWcjyHg@mail.gmail.com> (raw)
In-Reply-To: <SG2PR06MB11659AB956F83E8DCE2C9AA18A350@SG2PR06MB1165.apcprd06.prod.outlook.com>
On Wed, Mar 29, 2017 at 4:55 PM, Chris Brandt <Chris.Brandt@renesas.com> wrote:
> On Wednesday, March 29, 2017, Linus Walleij wrote:
>> On Fri, Mar 24, 2017 at 4:22 PM, Jacopo Mondi <jacopo+renesas@jmondi.org>
>> wrote:
>>
>> > Add dt-bindings for Renesas r7s72100 pin controller header file.
>> >
>> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
>>
>> > +/*
>> > + * Pin is bi-directional.
>> > + * An alternate function that needs both input/output functionalities
>> > +shall
>> > + * be configured as bidirectional.
>> > + * Eg. SDA/SCL pins of an I2c interface.
>> > + */
>> > +#define BI_DIR (1 << 3)
>>
>> Any specific reason why this should not simply be added to
>> include/linux/pinctrl/pinconf-generic.h
>> as PIN_CONFIG_BIDIRECTIONAL and parsed in drivers/pinctrl/pinconf-
>> generic.c from the (new) DT property "bidirectional" simply?
>
> I see your point. It would cut down from every driver out there
> inventing some new property or config instead of everyone just sharing
> a fixed set.
> Maybe someone else out there will end up having a need for a
> "bidirectional" option.
I was thinking about that one. It is a bit weird electrically, like what
kind of electronics is really bidirectional?
It seems like a fancy name for open drain/open source, what we
call "single ended" configuration. (See docs in
Documentation/gpio/driver.txt)
It would be great if you could check if that is what they mean,
actually.
> But, what do we do for Ethernet? All the pins are "normal" except just
> the MDIO pin needs to be bidirectional.
I see Geert clarified what we could do here.
Yours,
Linus Walleij
next prev parent reply other threads:[~2017-03-30 8:16 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-24 15:22 [PATCH v3 0/8] Renesas RZ/A1 pin and gpio controller Jacopo Mondi
2017-03-24 15:22 ` [PATCH v3 1/7] pinctrl: " Jacopo Mondi
2017-03-24 15:42 ` Linus Walleij
2017-03-24 16:45 ` jacopo
2017-03-29 1:43 ` Linus Walleij
2017-03-29 7:30 ` Geert Uytterhoeven
2017-03-29 10:03 ` Linus Walleij
2017-03-24 15:22 ` [PATCH v3 2/7] dt-bindings: pinctrl: Add RZ/A1 bindings doc Jacopo Mondi
2017-03-30 22:39 ` Rob Herring
2017-03-31 9:52 ` jacopo
2017-03-24 15:22 ` [PATCH v3 3/7] arm: dts: dt-bindings: Add Renesas RZ pinctrl header Jacopo Mondi
2017-03-29 13:22 ` Linus Walleij
2017-03-29 14:55 ` Chris Brandt
2017-03-29 14:59 ` Geert Uytterhoeven
2017-03-29 15:18 ` Chris Brandt
2017-03-29 15:39 ` Chris Brandt
2017-03-30 8:15 ` Linus Walleij [this message]
2017-03-30 13:27 ` Chris Brandt
2017-03-29 15:56 ` jacopo
2017-03-30 8:33 ` Linus Walleij
2017-03-24 15:22 ` [PATCH v3 4/7] arm: dts: r7s72100: Add pin controller node Jacopo Mondi
2017-03-24 15:32 ` Sergei Shtylyov
2017-03-27 17:12 ` Chris Brandt
2017-03-29 13:26 ` jacopo
2017-03-24 15:22 ` [PATCH v3 5/7] arm: dts: genmai: Add SCIF2 pin group Jacopo Mondi
2017-03-24 15:22 ` [PATCH v3 6/7] arm: dts: genmai: Add RIIC2 " Jacopo Mondi
2017-03-24 15:22 ` [PATCH v3 7/7] arm: dts: genmai: Add user led device nodes Jacopo Mondi
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