From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752770Ab1GTSkh (ORCPT ); Wed, 20 Jul 2011 14:40:37 -0400 Received: from hqemgate04.nvidia.com ([216.228.121.35]:13333 "EHLO hqemgate04.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752096Ab1GTSkg convert rfc822-to-8bit (ORCPT ); Wed, 20 Jul 2011 14:40:36 -0400 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Wed, 20 Jul 2011 11:40:29 -0700 From: Stephen Warren To: Grant Likely , Mark Brown CC: Erik Gilling , "linux-kernel@vger.kernel.org" , "linux-tegra@vger.kernel.org" , Colin Cross , Olof Johansson , "linux-arm-kernel@lists.infradead.org" , Russell King , Arnd Bergmann Date: Wed, 20 Jul 2011 11:40:28 -0700 Subject: RE: [PATCH] arm/dt: tegra devicetree support Thread-Topic: [PATCH] arm/dt: tegra devicetree support Thread-Index: AcxHC0FL8yktUj+ITnG+KyOGjI8bjAAAIgag Message-ID: <74CDBE0F657A3D45AFBB94109FB122FF049EBDEF01@HQMAIL01.nvidia.com> References: <20110719234158.2779.15394.stgit@ponder> <74CDBE0F657A3D45AFBB94109FB122FF049EBDEE27@HQMAIL01.nvidia.com> <20110720160355.GB2406@sirena.org.uk> <20110720183133.GE4642@ponder.secretlab.ca> In-Reply-To: <20110720183133.GE4642@ponder.secretlab.ca> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Grant Likely wrote at Wednesday, July 20, 2011 12:32 PM: > On Wed, Jul 20, 2011 at 05:03:55PM +0100, Mark Brown wrote: > > On Wed, Jul 20, 2011 at 08:37:19AM -0700, Stephen Warren wrote: > > > Grant Likely wrote at Tuesday, July 19, 2011 5:43 PM: > > > > > > + sound { > > > > + compatible = "nvidia,harmony-sound", "nvidia,tegra-wm8903"; > > > > > I thought the sound bindings were still somewhat experimental and not > > > completely agreed upon. One issue I see is that Device Tree is > > > supposed to represent pure HW, rather than driver-required abstractions, > > > and at least the compatible name here is pretty Linux-driver-specific. > > > > The current decision is that the schematic for embedded audio hardware > > is sufficiently interesting to be considered hardware in its own right > > separately to the chips contained within it. > > Correct. For complex composite devices like audio, it is completely > appropriate to have a root node that represents the entire complex and > how it is wired together. Sure, that makes sense. > The compatible property here definitely represents the hardware > because it reflects the sound infrastructure on the harmony board. I can see that argument for "nvidia,harmony-sound". But "nvidia,tegra-wm8903" is pretty generic; I can certainly see there being Tegra 20 systems that use a WM8903 but are so different from either Harmony or anything supported by sound/soc/tegra/tegra_wm8903.c that the existing driver isn't applicable. And hence, there may be a different ASoC driver for such board(s), and hence choosing such a generic name as "tegra-wm8903" for Harmony/Seaboard's audio layout seems like it might cause problems in the future. I'm fine with such a generic name for the platform driver, since that name can fairly easily be modified just by editing the driver and the board file. But since *.dts files are at least logically separate from the kernel, such naming future-proofing is a little more important. -- nvpublic