From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755363Ab0IHQzb (ORCPT ); Wed, 8 Sep 2010 12:55:31 -0400 Received: from opensource.wolfsonmicro.com ([80.75.67.52]:44405 "EHLO opensource2.wolfsonmicro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751405Ab0IHQz3 (ORCPT ); Wed, 8 Sep 2010 12:55:29 -0400 Date: Wed, 8 Sep 2010 17:55:27 +0100 From: Mark Brown To: Grant Likely Cc: Jassi Brar , Jassi Brar , David Brownell , spi-devel-general@lists.sourceforge.net, patches@opensource.wolfsonmicro.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] spi/spi_s3c64xx: Move to subsys_initcall() Message-ID: <20100908165526.GB15562@rakim.wolfsonmicro.main> References: <1283855357-15179-1-git-send-email-broonie@opensource.wolfsonmicro.com> <20100908091242.GB31253@rakim.wolfsonmicro.main> <20100908161245.GC3686@angua.secretlab.ca> <20100908162251.GA15562@rakim.wolfsonmicro.main> <20100908164432.GG3686@angua.secretlab.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100908164432.GG3686@angua.secretlab.ca> X-Cookie: Real programs don't eat cache. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 08, 2010 at 10:44:32AM -0600, Grant Likely wrote: > On Wed, Sep 08, 2010 at 05:22:51PM +0100, Mark Brown wrote: > > Doing dependencies could get pretty complicated, especially once you > > handle optional dependencies ("is this missing because it didn't probe > > yet or because it's just not there?") so it's not entirely clear to me > > that it's worth the hassle. > I think it might be doable. I had a similar problem with Ethernet > MACs and PHYs where the PHY was on a completely separate bus from the > MAC with zero guarantees on probe order. I had some code that made it > simple to use a bus notifier to defer MAC initialization until the > required phy turned up and was probed. I eventually abandoned it > because accessing the PHY could be deferred until .ndo_open() time. > However, it would be easy to resurrect, and might be a reasonable > solution. At the very least it is worth an investigation. If you've got stuff that'd be great - ASoC also has a deferral mechanism implemented due to this song and dance. Like I say, the main reason I've never looked at it myself is that it's never been sufficiently much of a practical problem for me to justify the effort.