From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 14 Sep 2007 11:22:49 +1000 From: David Gibson To: Olof Johansson Subject: Re: oftree and external connected devices Message-ID: <20070914012249.GB481@localhost.localdomain> References: <200709131326.27325.jbe@pengutronix.de> <20070913132913.GA9031@lixom.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20070913132913.GA9031@lixom.net> Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Sep 13, 2007 at 08:29:13AM -0500, Olof Johansson wrote: > On Thu, Sep 13, 2007 at 01:26:26PM +0200, Juergen Beisert wrote: > > Hi, > > > > I'm using an MPC5200B based system with various external connected devices to > > its LocalPlusBus. On other architectures I would register them as platform > > devices (no chance to autodetect these devices). But on PowerPC architecture? > > If it's a special case of something that it's unlikely that you'll reuse > the driver for, I'd say go ahead with a platform driver. There's nothing in the > PPC kernel that stops it from working. > > We're just trying to avoid it for common devices that platforms might share, > and instead of describing hardware in the platform devices setup, describe it > in the device tree instead. > > So it depends on how much work you want to invest in it, and if you're > planning on ever submitting the driver upstream. If you are, going > with a simple device tree definiton would be best (the kernel side, > to move a platform driver to instead be an of_platform driver is easy, > and can be done afterwards). > > > Is the oftree description also intended to describe these kind of external > > devices, or only SoC's internal devices? If its also intended for external > > devices, how to do so? Are there any examples? I didn't find anything useful > > yet. > > It can be used to describe on-board or off-board devices alike. And should be used to describe any devices that can't otherwise be probed, whether they're on-board or not. -- 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