From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: ASoC audio fabric OF bindings RFC. was: Re: ASoC MPC5xxx PSC AC97 audio driver Date: Mon, 12 Sep 2011 12:09:50 +0100 Message-ID: <20110912110950.GD2953@opensource.wolfsonmicro.com> References: <20110908121600.267dee07@archvile> <20110908124529.520c1388@archvile> <20110908163231.4b721973@archvile> <20110908184441.GD16989@siel.b> <20110909082844.3dbf0e72@archvile> <20110909120216.263eeb54@archvile> <20110909163714.GA4302@sirena.org.uk> <20110912083158.29d9e1fe@archvile> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20110912083158.29d9e1fe@archvile> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: David Jander Cc: Grant Likely , alsa-devel@alsa-project.org, lrg@ti.com, devicetree-discuss@lists.ozlabs.org, torbenh List-Id: devicetree@vger.kernel.org On Mon, Sep 12, 2011 at 08:31:58AM +0200, David Jander wrote: > Mark Brown wrote: > > This isn't really something that should go into device tree, ALSA is a > > Linux specific concept. > There are many Linux-specific details in Linux's implementation of Open > Firmware Device Trees. Right now, thanks to Linux, Open-Firmware device trees This is generally considered a bug in the bindings, the bindings are for cross-platform usage and should not be specific to any OS. > introduced in arch/arm right now. On all these platforms, its sole existence > is purely for running Linux with minimal board support code in the kernel. Other OSs are actively using device tree. > So, why not add a few more Linux-specific bits to it, if it helps get rid of > the last bit of board-specific code? Eliminating board specific code for audio is not a realistic goal, the configuration of modern audio subsystems is too complex and dynamic. It is realistic to make machine drivers which cover broad classes of devices with similar hardware. > The platforms that will use those bindings, will never have > Open-Firmware bioses in the first place, and their DT sources will be part of > the kernel source tree anyway. The plan is to push the device trees out of the kernel into a separate repository. > > What we should really be doing here is to autodiscover by reading the ID > > registers in the device. That needs generic AC'97 bus work which we > > don't have right now. > Seems reasonable, but is correct autodiscovery really possible for all > configurations and all DAI-codec combinations? Yes, it's a very basic part of AC'97.