From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 1A932474F2 for ; Fri, 22 Aug 2008 08:05:14 +1000 (EST) Subject: Re: [PATCH 0/3]: Sparc OF I2C support. From: Benjamin Herrenschmidt To: Scott Wood In-Reply-To: <48ADDF86.2040200@freescale.com> References: <20080821.001012.265401427.davem@davemloft.net> <20080821163256.GC15669@ld0162-tx32.am.freescale.net> <20080821.142134.127315039.davem@davemloft.net> <48ADDF86.2040200@freescale.com> Content-Type: text/plain Date: Fri, 22 Aug 2008 08:05:02 +1000 Message-Id: <1219356302.21386.147.camel@pasglop> Mime-Version: 1.0 Cc: sparclinux@vger.kernel.org, linuxppc-dev@ozlabs.org, paulus@samba.org, David Miller Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > 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.