From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Hesselbarth Subject: Re: [PATCH 1/2] ARM: Dove: Add the audio devices in DT Date: Wed, 28 Aug 2013 14:16:32 +0200 Message-ID: <521DEA20.8020103@gmail.com> References: <20130828113459.48ecbb34@armhf> <521DCD33.2070008@gmail.com> <20130828121943.1c8327ca@skate> <521DD057.4040208@gmail.com> <20130828131548.0009d613@skate> <521DE2B3.9050508@gmail.com> <20130828135827.2307c89e@skate> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130828135827.2307c89e@skate> Sender: linux-kernel-owner@vger.kernel.org To: Thomas Petazzoni Cc: Jean-Francois Moine , Mark Rutland , devicetree@vger.kernel.org, Russell King , Jason Cooper , Pawel Moll , Stephen Warren , linux-kernel@vger.kernel.org, Rob Herring , Gregory CLEMENT , linux-arm-kernel@lists.infradead.org, Ian Campbell List-Id: devicetree@vger.kernel.org On 08/28/13 13:58, Thomas Petazzoni wrote: > On Wed, 28 Aug 2013 13:44:51 +0200, Sebastian Hesselbarth wrote: >>>> Also, we'll need to distinguish between the different audio controllers >>>> on a single SoC, i.e. i2s0 and i2s1. I suggest checking the (phys) reg >>>> base passed. >>> >>> For what reason does the driver needs to know whether it's the instance >>> 0 or instance 1 ? If it's needed for some specific reason, then there >>> should probably be something like marvell,i2s-channel-id = <0> and >>> marvell,i2s-channel-id = <1>. >> >> On Dove, audio1 has SPDIF out, audio0 hasn't. Russell also mentioned to >> get rid of "i2s" and use "audio" instead. Most SoC's controllers are >> i2s only but as soon as SPDIF comes into play, it is a different >> interface protocol. >> >> I am fine with having a "marvell,channel-id" (no "i2s") to discriminate >> the instances, although reg offset should be sufficient. > > Well, the reg offset is a possibility, but it's not really nice, and > would have to be adapted to each and every SoC even if the reset of the > audio IP is the same. > > Though, if the difference between the two units is the availability of > SPDIF support, then we shouldn't encode the channel number, but instead > the availability of SPDIF, i.e: > > audio0 { > reg = <... ...>; > compatible = "marvell,kirkwood-audio"; > marvell,has-spdif; Agree, if you make it "marvell,has-spdif-in" and "marvell,has-spdif-out" Dove has either i2s-only or i2s+spdifo, kirkwood has i2s+spdifo+spdifi for the one audio controller available. Can't tell for Armada 370. BTW, you might have followed some of the DT discussions with Mark before; as he insists on having a separate sound card node, he might argue that above property should be part of that node instead. Last patch discussion [1] I followed on some spdif sound nodes, took the patch up to v11 or so. Mainly, because the author updated it too quickly, but looks like audio bindings are (still) worth a lot of discussion. [1] http://comments.gmane.org/gmane.linux.alsa.devel/112004 Sebastian > }; > > audio1 { > reg = <... ...>; > compatible = "marvell,kirkwood-audio"; > };