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From: Timur Tabi <timur@freescale.com>
To: <devicetree-discuss@lists.ozlabs.org>, <linuxppc-dev@lists.ozlabs.org>
Subject: Endianness of multi-bit 'gpios' property?
Date: Tue, 7 Aug 2012 15:39:22 -0500	[thread overview]
Message-ID: <50217CFA.7040708@freescale.com> (raw)

When a 'gpios' property defines multiple GPIO pins, is there any kind of
expectation on the endian order of those pins?  For example, take this:

	gpios = <&gpio0 0 0
		 &gpio0 1 0>;

If I write a value of "2" to this GPIO pair, should I expect a value of 1
to be written to pin 0 and a value of 0 written to pin 1 (i.e.
big-endian), or the other way around?

I'm seeing some code that interprets the bits as big-endian, and some code
that interprets it as little-endian.

-- 
Timur Tabi
Linux kernel developer at Freescale

WARNING: multiple messages have this Message-ID (diff)
From: Timur Tabi <timur-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
To: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
	linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
Subject: Endianness of multi-bit 'gpios' property?
Date: Tue, 7 Aug 2012 15:39:22 -0500	[thread overview]
Message-ID: <50217CFA.7040708@freescale.com> (raw)

When a 'gpios' property defines multiple GPIO pins, is there any kind of
expectation on the endian order of those pins?  For example, take this:

	gpios = <&gpio0 0 0
		 &gpio0 1 0>;

If I write a value of "2" to this GPIO pair, should I expect a value of 1
to be written to pin 0 and a value of 0 written to pin 1 (i.e.
big-endian), or the other way around?

I'm seeing some code that interprets the bits as big-endian, and some code
that interprets it as little-endian.

-- 
Timur Tabi
Linux kernel developer at Freescale

             reply	other threads:[~2012-08-07 20:39 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-07 20:39 Timur Tabi [this message]
2012-08-07 20:39 ` Endianness of multi-bit 'gpios' property? Timur Tabi

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