From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ch1outboundpool.messaging.microsoft.com (ch1ehsobe002.messaging.microsoft.com [216.32.181.182]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "Microsoft Secure Server Authority" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id B61E5B6F75 for ; Fri, 2 Dec 2011 05:41:53 +1100 (EST) Message-ID: <4ED7CA64.2080503@freescale.com> Date: Thu, 1 Dec 2011 12:41:40 -0600 From: Scott Wood MIME-Version: 1.0 To: Timur Tabi Subject: Re: [PATCH] i2c-mpc: use the cell-index property to enumerate the I2C adapters References: <1322760781-31226-1-git-send-email-timur@freescale.com> In-Reply-To: <1322760781-31226-1-git-send-email-timur@freescale.com> Content-Type: text/plain; charset="ISO-8859-1" Cc: linuxppc-dev@ozlabs.org, kumar.gala@freescale.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 12/01/2011 11:33 AM, Timur Tabi wrote: > An I2C device tree node can contain a 'cell-index' property that can be > used to enumerate the I2C devices. If such a property exists, use it > to specify the I2C adapter number. Didn't we decide a long time ago that this was a bad idea? > This feature is necessary for the Freescale PowerPC audio drivers (e.g. > on the P1022DS). The "machine driver" needs to know the adapter number > for each I2C adapter, but it only has access to the device tree. > Previously, the I2C nodes always appeared in cell-index order, so the > dynamic numbering coincided with the cell-index property. With commit > ab827d97 ("powerpc/85xx: Rework P1022DS device tree"), the I2C nodes are > unintentionally reversed in the device tree, and so the machine driver > guesses the wrong I2C adapter number. What specifically do you need this number for? What does it represent? -Scott