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From: Mark Brown <broonie@kernel.org>
To: Dmitry Eremin-Solenikov <dmitry_eremin@mentor.com>
Cc: Dirk Behme <dirk.behme@de.bosch.com>,
	linux-kernel@vger.kernel.org, Liam Girdwood <lgirdwood@gmail.com>,
	Gokulkrishnan Nagarajan <Gokulkrishnan.Nagarajan@in.bosch.com>,
	Grant Likely <grant.likely@secretlab.ca>,
	Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH] regulator: core: GPIO #0 is a valid GPIO
Date: Mon, 1 Sep 2014 13:06:02 +0100	[thread overview]
Message-ID: <20140901120602.GT29327@sirena.org.uk> (raw)
In-Reply-To: <54045FA6.70602@mentor.com>

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On Mon, Sep 01, 2014 at 03:59:34PM +0400, Dmitry Eremin-Solenikov wrote:
> On 09/01/2014 02:15 PM, Mark Brown wrote:

> >There's no practical way to deploy that without breaking users - as soon
> >as you treat 0 as a valid GPIO you make all existing users relying on
> >the natural behaviour of treating 0 as default instantly buggy which is
> >not practical.  Really the GPIO API is badly specified here.

> Back in the time before DTS conversion started, the 0 was a correct GPIO
> number. If somebody wanted to specify that no gpio is provided, he provided
> -1 as an invalid number. I have the feeling that allowing users to use 0 as
> 'no gpio' is a mistake. Or the API should be changed
> to disallow GPIO 0 to exist at all.

Please consider my point about making users instantly buggy - it's not
practical to introduce a new field into existing platform data which
needs initialization.  Disallowing the use of 0 as a GPIO seems more
practical here (in that it's something the platform can control with
more reliable coordination).

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  reply	other threads:[~2014-09-01 12:06 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-29 18:19 Dmitry Eremin-Solenikov
2014-08-29 19:01 ` Mark Brown
2014-09-01  7:46   ` Dirk Behme
2014-09-01  7:55     ` Geert Uytterhoeven
2014-09-01 10:15     ` Mark Brown
2014-09-01 11:59       ` Dmitry Eremin-Solenikov
2014-09-01 12:06         ` Mark Brown [this message]
2014-09-01 12:35           ` Dmitry Eremin-Solenikov
2014-09-01 12:49             ` Mark Brown
2014-09-03  9:04               ` Dmitry Eremin-Solenikov
2014-09-03 11:01                 ` Mark Brown
2014-09-04 17:15         ` Linus Walleij
2014-09-04 17:19     ` Linus Walleij

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