From: Linus Walleij <linus.walleij@linaro.org>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [periperi] How to set default GPIO pin ?
Date: Mon, 29 Sep 2014 08:58:03 +0000 [thread overview]
Message-ID: <CACRpkdZg7_edUiAaGq_YPLyT4gCfOcZ8463rYb=hD0Xqr4gOYg@mail.gmail.com> (raw)
In-Reply-To: <2033766.6tR9OHe7ZC@avalon>
On Sun, Sep 28, 2014 at 11:25 PM, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> Hi Linus and Morimoto-san,
>
> On Tuesday 23 September 2014 17:06:28 Linus Walleij wrote:
>> On Wed, Sep 10, 2014 at 10:55 AM, Laurent Pinchart wrote:
>> > On Sunday 31 August 2014 22:08:52 Kuninori Morimoto wrote:
>> >> I know we can use "defalt" PFC settings on DT.
>> >> But, how to use "defalt" GPIO pin settings on DT ?
>> >>
>> >> We would like to use GPIO 7-17 as Low output,
>> >> and do nothing after boot.
>> >
>> > From a DT point of view I believe this is supposed to be done by
>> > specifying the output-low or output-high properties in the pinctrl
>> > configuration node. However, these properties are not supported by the PFC
>> > driver, and there's no easy way for the PFC driver to configure GPIOs
>> > handled by a different driver such as the gpio-rcar driver for instance.
>> >
>> > Linus, do you have any hindsight on how this should be implemented ?
>>
>> I have suggested adding GPIO hogs, so that a GPIO node can specify
>> that some GPIO's specified on the local ship be hogged high or
>> low at probe. Generic DT bindings and generic code in gpiolib.c.
>>
>> gpios-hog-high = <....>;
>> gpios-hog-low = <....>;
>
> How about just a gpios-hog property, with a list of gpio specifiers + flags ?
> That's bikeshedding I suppose.
>
> Morimoto-san, would you like to implement that ? :-)
There was a proposed implementation from Boris BREZILLON, but I was
unhappy with parts of it, however check it and see my comments on
the patch set:
"[RFC PATCH] gpio: add GPIO hogging mechanism"
Yours,
Linus Walleij
WARNING: multiple messages have this Message-ID (diff)
From: Linus Walleij <linus.walleij@linaro.org>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Boris BREZILLON <boris.brezillon@free-electrons.com>
Cc: "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
Kuninori Morimoto <kuninori.morimoto.gx@gmail.com>,
"goda (Renesas)" <yusuke.goda.sx@renesas.com>,
"linux-sh@vger.kernel.org" <linux-sh@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [periperi] How to set default GPIO pin ?
Date: Mon, 29 Sep 2014 10:58:03 +0200 [thread overview]
Message-ID: <CACRpkdZg7_edUiAaGq_YPLyT4gCfOcZ8463rYb=hD0Xqr4gOYg@mail.gmail.com> (raw)
In-Reply-To: <2033766.6tR9OHe7ZC@avalon>
On Sun, Sep 28, 2014 at 11:25 PM, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> Hi Linus and Morimoto-san,
>
> On Tuesday 23 September 2014 17:06:28 Linus Walleij wrote:
>> On Wed, Sep 10, 2014 at 10:55 AM, Laurent Pinchart wrote:
>> > On Sunday 31 August 2014 22:08:52 Kuninori Morimoto wrote:
>> >> I know we can use "defalt" PFC settings on DT.
>> >> But, how to use "defalt" GPIO pin settings on DT ?
>> >>
>> >> We would like to use GPIO 7-17 as Low output,
>> >> and do nothing after boot.
>> >
>> > From a DT point of view I believe this is supposed to be done by
>> > specifying the output-low or output-high properties in the pinctrl
>> > configuration node. However, these properties are not supported by the PFC
>> > driver, and there's no easy way for the PFC driver to configure GPIOs
>> > handled by a different driver such as the gpio-rcar driver for instance.
>> >
>> > Linus, do you have any hindsight on how this should be implemented ?
>>
>> I have suggested adding GPIO hogs, so that a GPIO node can specify
>> that some GPIO's specified on the local ship be hogged high or
>> low at probe. Generic DT bindings and generic code in gpiolib.c.
>>
>> gpios-hog-high = <....>;
>> gpios-hog-low = <....>;
>
> How about just a gpios-hog property, with a list of gpio specifiers + flags ?
> That's bikeshedding I suppose.
>
> Morimoto-san, would you like to implement that ? :-)
There was a proposed implementation from Boris BREZILLON, but I was
unhappy with parts of it, however check it and see my comments on
the patch set:
"[RFC PATCH] gpio: add GPIO hogging mechanism"
Yours,
Linus Walleij
WARNING: multiple messages have this Message-ID (diff)
From: linus.walleij@linaro.org (Linus Walleij)
To: linux-arm-kernel@lists.infradead.org
Subject: [periperi] How to set default GPIO pin ?
Date: Mon, 29 Sep 2014 10:58:03 +0200 [thread overview]
Message-ID: <CACRpkdZg7_edUiAaGq_YPLyT4gCfOcZ8463rYb=hD0Xqr4gOYg@mail.gmail.com> (raw)
In-Reply-To: <2033766.6tR9OHe7ZC@avalon>
On Sun, Sep 28, 2014 at 11:25 PM, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> Hi Linus and Morimoto-san,
>
> On Tuesday 23 September 2014 17:06:28 Linus Walleij wrote:
>> On Wed, Sep 10, 2014 at 10:55 AM, Laurent Pinchart wrote:
>> > On Sunday 31 August 2014 22:08:52 Kuninori Morimoto wrote:
>> >> I know we can use "defalt" PFC settings on DT.
>> >> But, how to use "defalt" GPIO pin settings on DT ?
>> >>
>> >> We would like to use GPIO 7-17 as Low output,
>> >> and do nothing after boot.
>> >
>> > From a DT point of view I believe this is supposed to be done by
>> > specifying the output-low or output-high properties in the pinctrl
>> > configuration node. However, these properties are not supported by the PFC
>> > driver, and there's no easy way for the PFC driver to configure GPIOs
>> > handled by a different driver such as the gpio-rcar driver for instance.
>> >
>> > Linus, do you have any hindsight on how this should be implemented ?
>>
>> I have suggested adding GPIO hogs, so that a GPIO node can specify
>> that some GPIO's specified on the local ship be hogged high or
>> low at probe. Generic DT bindings and generic code in gpiolib.c.
>>
>> gpios-hog-high = <....>;
>> gpios-hog-low = <....>;
>
> How about just a gpios-hog property, with a list of gpio specifiers + flags ?
> That's bikeshedding I suppose.
>
> Morimoto-san, would you like to implement that ? :-)
There was a proposed implementation from Boris BREZILLON, but I was
unhappy with parts of it, however check it and see my comments on
the patch set:
"[RFC PATCH] gpio: add GPIO hogging mechanism"
Yours,
Linus Walleij
next prev parent reply other threads:[~2014-09-29 8:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <8738cc0vx9.wl%kuninori.morimoto.gx@gmail.com>
2014-09-10 8:55 ` [periperi] How to set default GPIO pin ? Laurent Pinchart
2014-09-10 8:55 ` Laurent Pinchart
2014-09-12 7:27 ` Kuninori Morimoto
2014-09-12 7:27 ` Kuninori Morimoto
2014-09-23 15:06 ` Linus Walleij
2014-09-23 15:06 ` Linus Walleij
2014-09-23 15:06 ` Linus Walleij
2014-09-28 21:25 ` Laurent Pinchart
2014-09-28 21:25 ` Laurent Pinchart
2014-09-28 21:25 ` Laurent Pinchart
2014-09-28 23:58 ` Kuninori Morimoto
2014-09-28 23:58 ` Kuninori Morimoto
2014-09-28 23:58 ` Kuninori Morimoto
2014-09-29 8:58 ` Linus Walleij [this message]
2014-09-29 8:58 ` Linus Walleij
2014-09-29 8:58 ` Linus Walleij
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