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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Scott Wood <scottwood@freescale.com>
Cc: sparclinux@vger.kernel.org, linuxppc-dev@ozlabs.org,
	paulus@samba.org, David Miller <davem@davemloft.net>
Subject: Re: [PATCH 0/3]: Sparc OF I2C support.
Date: Fri, 22 Aug 2008 08:05:02 +1000	[thread overview]
Message-ID: <1219356302.21386.147.camel@pasglop> (raw)
In-Reply-To: <48ADDF86.2040200@freescale.com>


> It's not really an instruction-set architecture issue, it's a binding 
> issue.  What if a non-OF embedded SPARC comes along that copies i2c from 
> a PowerPC DTS file, or we come across a real-OF PowerPC that does it the 
> SPARC way?

Like PowerMac ? :-)

Apple additionally have different ways of representing multiple busses
on one controller though. On some machines, they just use bits 0xF00 of
the address as the bus number, which is a bit gross, and on some, they
have sub-nodes i2c-bus@NN under the controller.

But at least the address encoding (shifted by 1 bit) is common with sparc
and I think is a fairly common way of representing i2c addresses.

> As far as I can tell from poking around 
> http://penguinppc.org/historical/dev-trees-html/, they don't include reg 
> at all for i2c clients.

Most of the device-trees on penguinppc.org are obsolete. i2c is mostly
used in the device-tree for newer stuff such as G5s.

Ben.

  parent reply	other threads:[~2008-08-21 22:05 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-21  7:10 [PATCH 0/3]: Sparc OF I2C support David Miller
2008-08-21 16:32 ` Scott Wood
2008-08-21 21:21   ` David Miller
2008-08-21 21:35     ` Scott Wood
2008-08-21 21:45       ` David Miller
2008-08-21 22:05         ` Benjamin Herrenschmidt
2008-08-21 22:27           ` David Miller
2008-08-21 22:38             ` Benjamin Herrenschmidt
2008-08-21 22:05       ` Benjamin Herrenschmidt [this message]
2008-08-21 22:28         ` David Miller
2008-08-21 22:39           ` Benjamin Herrenschmidt
2008-08-21 23:14       ` Grant Likely
2008-08-21 23:32         ` David Miller
2008-08-22  1:15           ` Josh Boyer
2008-08-22  3:53             ` David Miller
2008-08-22  4:18               ` Grant Likely
2008-08-22  4:22                 ` David Miller
2008-08-22  4:29                   ` Mitch Bradley
2008-08-22  4:30                     ` Grant Likely
2008-08-22  4:34                       ` Grant Likely
2008-08-22  4:37                         ` David Miller
2008-08-22  5:19                           ` Mitch Bradley
2008-08-22 16:00                             ` Yoder Stuart
2008-08-22 16:13                               ` Josh Boyer
2008-08-22 10:50               ` Josh Boyer
2008-08-22 11:06                 ` David Miller
2008-08-21 23:45         ` Jon Smirl
2008-08-22  2:33           ` Grant Likely
2008-08-22  2:39             ` Jon Smirl
2008-08-22 15:58               ` Scott Wood
2008-08-22 16:44               ` Grant Likely
2008-08-21 22:01   ` Benjamin Herrenschmidt
2008-08-21 21:53 ` Jon Smirl
2008-08-21 21:58   ` David Miller

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