Re: [PATCH] regulator: core: GPIO #0 is a valid GPIO

Mark Brown
2014-09-01T12:06:26Z

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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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