From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 25 Oct 2007 10:04:25 +1000 From: David Gibson To: Grant Likely Subject: Re: Audio codec device tree entries Message-ID: <20071025000425.GD23694@localhost.localdomain> References: <8416ea754e013a67441aec778c81ad73@kernel.crashing.org> <9e4733910710231529h1089eacdy888306f20af92555@mail.gmail.com> <471F52ED.10007@freescale.com> <9e4733910710240800y24952e70g8c318e35e2e45e2e@mail.gmail.com> <9e4733910710240828x412f598dy7fc4a75faa76358d@mail.gmail.com> <9e4733910710240854y6ac115b6i5e0400eb369fcf7@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Cc: PowerPC dev list , Timur Tabi List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Oct 24, 2007 at 10:38:11AM -0600, Grant Likely wrote: > On 10/24/07, Jon Smirl wrote: > > On 10/24/07, Grant Likely wrote: [snip] > > > For example: > > > sound@0 { > > > compatible = ",,sound" // The board might have > > > more than one sound i/f which could be wired differently > > > codec-handle = <&codec0>; > > > }; > > The difference here is that the node provides real information about > the board. It has a compatible field which tells you *exactly* what > sound circuit is present on the board. It can have additional > information that does make sense to encode into the device tree (ie. > the codec that is used). It's not addressable (no registers or > anything), but it does describe the board. > > It would be possible and reasonable for a single fabric driver to work > with many different circuit layouts as long as it has the information > needed to adapt each instance. This still seems nasty, since it seems to do little but duplicate the platform information. I'm afraid I still don't understand quite what information this "fabric" driver is conveying. Is it really inherently platform specific, or is it something that can be encoded directly in a sensible way. If the latter we could have a general "device tree" fabric driver that will handle all systems with the layout correctly encoded in the device tree. -- 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