From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH v5 04/12] spi: add ti-ssp spi master driver Date: Tue, 16 Nov 2010 11:34:09 +0000 Message-ID: <20101116113409.GH3338@sirena.org.uk> References: <1289848334-8695-1-git-send-email-cyril@ti.com> <1289848334-8695-5-git-send-email-cyril@ti.com> <20101116072225.GF4074@angua.secretlab.ca> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: davinci-linux-open-source@linux.davincidsp.com, dbrownell@users.sourceforge.net, sameo@linux.intel.com, khilman@deeprootsystems.com, linus.ml.walleij@gmail.com, rpurdie@rpsys.net, linux-arm-kernel@lists.infradead.org, Cyril Chemparathy , spi-devel-general@lists.sourceforge.net, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, lrg@slimlogic.co.uk To: Grant Likely Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org List-Id: linux-spi.vger.kernel.org On Tue, Nov 16, 2010 at 12:47:04AM -0700, Grant Likely wrote: > On Tue, Nov 16, 2010 at 12:22 AM, Grant Likely > > Instead, it is now incumbent on the board support code to ensure that > > any device that depends on another device (including i2c or spi > > regulators) will defer registration until the prerequisite devices are > > bound to drivers. You did also say you were going to write helpers to make this easier - I do fear that we're going to end up with far too much boiler plate code in machine drivers if we have to open code this. I guess device tree is going to need the helpers anyway :) > > I don't *think* this change will affect anything in this particular > > patch series, but if it does then let me know and I'll help you work out > > how to fix it using a bus notifier. > Oh, wait, spoke too soon. You do add a regulator in this series, so > this change will require a fixup. The solution is to register an > bus_notifier to the spi bus type before you start registering devices. > It also requires deferring the musb_hdrc.1 and tps6116x registrations > until the bus_notifier callback gets called with an indication that > the regulator is bound. It will look something like this: Did you come up with a way of handling situations like cpufreq where we have no device to wait for?