From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rn-out-0910.google.com (rn-out-0910.google.com [64.233.170.189]) by ozlabs.org (Postfix) with ESMTP id 75B88DDF0E for ; Mon, 7 Jul 2008 23:23:27 +1000 (EST) Received: by rn-out-0910.google.com with SMTP id j40so356016rnf.16 for ; Mon, 07 Jul 2008 06:23:24 -0700 (PDT) Message-ID: <9e4733910807070623u4c17b319p48e96a3022f3459b@mail.gmail.com> Date: Mon, 7 Jul 2008 09:23:24 -0400 From: "Jon Smirl" To: "Grant Likely" , liam.girdwood@wolfsonmicro.com, alsa-devel@alsa-project.org, linuxppc-dev@ozlabs.org, timur@freescale.com Subject: Re: [alsa-devel] [PATCH 2/3] ALSA SoC: Add mpc5200-psc I2S driver In-Reply-To: <20080707105905.GA19240@rakim.wolfsonmicro.main> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 References: <20080701235330.16923.67218.stgit@trillian.secretlab.ca> <20080701235335.16923.43253.stgit@trillian.secretlab.ca> <9e4733910807061056m7b0dbf1fr578cbfcda31586ea@mail.gmail.com> <20080707105905.GA19240@rakim.wolfsonmicro.main> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 7/7/08, Mark Brown wrote: > On Sun, Jul 06, 2008 at 01:56:48PM -0400, Jon Smirl wrote: > > > The driver is assuming a capture stream exists. My codec is output only. > > > While the driver declares a capture stream the core doesn't require that > both capture and playback be available - it will cope with a capture > only or a playback only DAI (this is fairly common due to DAC only and > ADC only parts). Unless there's some other issue specific to this > driver? Yes, it GPFs allocating a a DMA buffer on the null capture stream pointer. > > > I'm using external clocking, but the driver should support using the > > mpc5200 for clocking. That's a little complicated since you have to > > compute the divisors. For example the Phytec pcm030 board has a > > 33.3333Mhz xtal and runs at 400Mhz. > > > This is desirable, though it shouldn't be an obstacle for merging if the > driver only supports running in slave mode. > > > > In order to reduce options, can the psc-i2s driver always try to use > > mpc5200 clocking, then let the codec or fabric driver override it? > > > The clocking should always be under the control of the machine driver > with the codec and platform drivers exporting the required dividers and > PLLs/FLLs. Neither the platform driver nor the codec driver are really > in a position to know how a given board is wired up and what > interdependencies or external requirements there are. > -- Jon Smirl jonsmirl@gmail.com