Re: [PATCH 3/3 v2] at91/atmel-mci: inclusion of sd/mmc driver in at91sam9g45 chip and board

[Ben Nizette <bn@niasdigital.com>]

On Wed, 2009-10-28 at 21:53 +0200, Andrew Victor wrote:
> hi,
> 
> > Then I think it would be best to use GPIO_PIN_NONE. Makes it clear
> > what is expected and avoids confusion on what should be the proper
> > value.
> > I hope I'm not saying non-sense, but even if I am, I guess you can see
> > that I'm advocating against the magic numbers :)
> 
> What magic numbers ?

I think Thiago was referring to the "-1" in the original patch as the
magic number.

Leaving the field blank to be initialised to 0 is certainly the
cleanest, I agree, but it doesn't actually /work/.  On many archs 0 is a
valid gpio number; the gpio_is_valid check used throughout the kernel
(including atmel-mci.c) looks like

static inline int gpio_is_valid(int number)
{
	/* only some non-negative numbers are valid */
	return ((unsigned)number) < ARCH_NR_GPIOS;
}

	--Ben.