From: Marek Vasut <marek.vasut@gmail.com>
To: Harald Geyer <harald@ccbib.org>
Cc: devicetree@vger.kernel.org,
Marek Vasut <marek.vasut+renesas@gmail.com>,
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
Linus Walleij <linus.walleij@linaro.org>,
Mark Brown <broonie@kernel.org>, Rob Herring <robh@kernel.org>,
linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH] regulator: gpio: Reword the binding document
Date: Tue, 19 Feb 2019 03:51:43 +0100 [thread overview]
Message-ID: <72363317-8259-eda2-4cd8-4f336f0c155f@gmail.com> (raw)
In-Reply-To: <E1gvrEx-0000K7-Ks@stardust.g4.wien.funkfeuer.at>
On 2/18/19 11:18 PM, Harald Geyer wrote:
> Marek Vasut writes:
>> So what about
>>
>> gpios-states : Initial state of GPIO pins in "gpios" array, set on
>> system start and retained until consumer changes the state. 0: LOW, 1:
>> HIGH. Default is LOW if nothing else is specified.
>
> No. "retained until consumer changes the state" is promising more then
> is guaranteed.
>
> From the explanations provided by Mark it is clear that this property
> is an artifact of the implementation in linux. I think we should document
> is as such. How about:
>
> gpios-states : On operating systems, that don't support reading back gpio
> values in output mode (most notably linux), this array
> provides the state of GPIO pins set when requesting them
> from the gpio controller.
That's good.
> Systems, that are capable of
> preserving state when requesting the lines, are free to
> ignore this property.
Are they ? I think there are systems which depend on preconfiguring the
GPIO according to this property.
> 0: LOW, 1: HIGH. Default is LOW if
> nothing else is specified.
>
> HTH,
> Harald
>
--
Best regards,
Marek Vasut
next prev parent reply other threads:[~2019-02-19 2:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-16 17:48 [PATCH] regulator: gpio: Reword the binding document marek.vasut
2019-02-16 20:20 ` Harald Geyer
2019-02-16 21:37 ` Marek Vasut
2019-02-17 14:26 ` Harald Geyer
2019-02-17 14:45 ` Marek Vasut
2019-02-17 20:00 ` Harald Geyer
2019-02-17 21:57 ` Marek Vasut
2019-02-18 10:04 ` Harald Geyer
2019-02-18 18:58 ` Marek Vasut
2019-02-18 22:18 ` Harald Geyer
2019-02-19 2:51 ` Marek Vasut [this message]
2019-02-19 10:10 ` Harald Geyer
2019-03-02 14:55 ` Marek Vasut
2019-03-03 16:07 ` Harald Geyer
2019-03-03 16:08 ` Marek Vasut
2019-02-18 18:01 ` Mark Brown
2019-02-18 17:56 ` Mark Brown
2019-02-18 17:54 ` Mark Brown
2019-02-18 9:30 ` Geert Uytterhoeven
2019-02-18 18:36 ` Marek Vasut
2019-02-18 19:21 ` Geert Uytterhoeven
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