From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cam-admin0.cambridge.arm.com (cam-admin0.cambridge.arm.com [217.140.96.50]) by ozlabs.org (Postfix) with ESMTP id 976542C0111 for ; Mon, 19 Aug 2013 20:01:57 +1000 (EST) Date: Mon, 19 Aug 2013 11:01:43 +0100 From: Mark Rutland To: Nicolin Chen , "broonie@kernel.org" Subject: Re: [PATCH v7 2/2] ASoC: fsl: Add S/PDIF machine driver Message-ID: <20130819100143.GH3719@e106331-lin.cambridge.arm.com> References: <20130819092458.GE3719@e106331-lin.cambridge.arm.com> <20130819095042.GA11402@MrMyself> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20130819095042.GA11402@MrMyself> Cc: "devicetree@vger.kernel.org" , "alsa-devel@alsa-project.org" , "lars@metafoo.de" , "swarren@wwwdotorg.org" , "festevam@gmail.com" , "s.hauer@pengutronix.de" , "timur@tabi.org" , "rob.herring@calxeda.com" , "tomasz.figa@gmail.com" , "p.zabel@pengutronix.de" , "R65777@freescale.com" , "shawn.guo@linaro.org" , "linuxppc-dev@lists.ozlabs.org" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Aug 19, 2013 at 10:50:43AM +0100, Nicolin Chen wrote: > Hi, > > On Mon, Aug 19, 2013 at 10:24:58AM +0100, Mark Rutland wrote: > > Is this used semantically, or is it a completely arbitrary string? In > > either case I don't see why the compatible string doesn't give the > > driver enough to have a sensible value. > > > > I'm confused as to why we need this. The phrase "user-visible" in a > > device description seems very odd. > > The string would be in the ALSA device list: > ALSA device list: > #0: imx-spdif > > I think it can be a sort of arbitrary as long as users know which this > device exactly is when they catch the name by 'aplay -l' or 'arecord -l' > > The phrase "user-visible" is being used in many current docs, I don't > dare to change it unless a sage gives me a suggestion. I can see that there is entrenched usage, but this really seems to be embedding Linux-specific implementation details into the dt. I don't see why the driver cannot select a sensible name, but perhaps I'm missing something. Mark, is there any reason we need to handle the user-visible name of the device this way? > > > > + > > > + - spdif-controller : The phandle of the i.MX S/PDIF controller > > > + > > > + > > > +Optional properties: > > > + > > > + - spdif-transmitter : The phandle of the spdif-transmitter dummy codec > > > + > > > + - spdif-receiver : The phandle of the spdif-receiver dummy codec > > > + > > > +* Note: At least one of these two properties should be set in the DT binding. > > > > Are all four units (comlpex,controller,transmitter,receiver) really > > separate blocks? > > At least they are separate drivers as I mentioned in the commit comments. I'm not sure that the boundary of Linux drivers should necessarily determine the way we carve up the description of IP blocks, though presumably it's a pretty sensible way of carving it up or we wouldn't have done it. Is there any public documentation on the i.MX S/PDIF hardware block(s)? Thanks, Mark.