From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932683AbYEVDkB (ORCPT ); Wed, 21 May 2008 23:40:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758197AbYEVDia (ORCPT ); Wed, 21 May 2008 23:38:30 -0400 Received: from smtp105.sbc.mail.mud.yahoo.com ([68.142.198.204]:36127 "HELO smtp105.sbc.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1757749AbYEVDi3 (ORCPT ); Wed, 21 May 2008 23:38:29 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=TL0dPwonZWyOPdeuYMYsrA/ezgjfp4itazbVk/vOIqJZkKtyyzcG348DP9oZjDJQ4aFhkryRwe9jvoWt+3brMcq6mza/dySOWaO188Gr97RTEueM5hibNnIxtIWDfPL8H4bPbj9UDzHQJs6Ml93RrWxWoshiS+XbaIiA6M0q5jY= ; X-YMail-OSG: WfYWwoIVM1mkpulBrI1bZeYfVlufwRqCNpxOuohwQMXP7UXFXf5CdWGsR3xSQ4H8RpSVo7M0z85nB.Pw0q2tItFZK0E8G8Ol5KlzVSej5IzK451UkVrrHFritXEYdMbx.xg- X-Yahoo-Newman-Property: ymail-3 From: David Brownell To: "Grant Likely" Subject: Re: [PATCH 3/4] spi: Add OF binding support for SPI busses Date: Wed, 21 May 2008 18:16:10 -0700 User-Agent: KMail/1.9.9 Cc: cbouatmailru@gmail.com, linuxppc-dev@ozlabs.org, spi-devel-general@lists.sourceforge.net, linux-kernel@vger.kernel.org, fabrizio.garetto@gmail.com References: <20080516193054.28030.35126.stgit@trillian.secretlab.ca> <20080516224916.GA16702@zarina> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Content-Disposition: inline Message-Id: <200805211816.10753.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 16 May 2008, Grant Likely wrote: > In my mind; platform_data and the device tree are all about the same > thing: representation.  In other words, how to describe the > configuration of the hardware independent of the driver itself. Platform_data isn't what I'd call independent of drivers. The reason the data is there in the first place is that the driver needs it ... and chose not to hard-wire it. > One of the things I find rather interesting is just how frequently > drivers using platform data structures have a big block of code which > simply copy pdata fields into identically named fields in the device > private data... ... because platform data was designed as a partial template for that driver, letting it do that. (Sometimes without even doing scale conversions.) As drivers grow functionally, they sometimes end up needing more platform data fields, to expose data that previously didn't matter. Whether that data can usefully be stored in flash (or ROM) and handed out through the bootloader is something of a manufacturing issue. - Dave