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Date: Tue, 28 Oct 2008 11:15:11 +1100
From: David Gibson <david@gibson.dropbear.id.au>
To: Matt Sealey <matt@genesi-usa.com>
Subject: Re: GPIO - marking individual pins (not) available in device tree
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On Mon, Oct 27, 2008 at 10:40:12AM -0500, Matt Sealey wrote:
>
>
> David Gibson wrote:
>
>> Um.. I can't actually follow what you're getting at there, sorry.
>
> Imagine in your head that you have a GPIO controller that has a
> 32-bit register potentially controlling 32 pins on the chip.
>
> Imagine that rather than being able to allocate 6 GPIO pins
> *right next to each other* in the register and saying that
> you start at "pin" 15 and use the next 6 "pins", you have to
> spread it around and use pin 1, pin 8, pin 9, pin 11, pin 15,
> pin 30, to make up this peripheral.
>
> As far as I can tell there is no way at all to specify a set of
> GPIO pins which are NOT consecutive because the current GPIO
> spec stops after specifying a controller bank (the 32-bit
> register).

Uh.. no.  The gpio specifier has a format that's gpio controller
specific, but it must include the actual pin number, although exactly
how it's encoded might vary.

So, you use
	gpios = <&controller pin1-specifier &controller pin8-specifier
		 &controller pin9-specifier &controller pin11-specifier
		 &controller pin15-specifier &controller pin30-specifier>;

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson