Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756623AbZJGXpY (ORCPT ); Wed, 7 Oct 2009 19:45:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756588AbZJGXpV (ORCPT ); Wed, 7 Oct 2009 19:45:21 -0400 Received: from mail-pz0-f177.google.com ([209.85.222.177]:51849 "EHLO mail-pz0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756581AbZJGXpU convert rfc822-to-8bit (ORCPT ); Wed, 7 Oct 2009 19:45:20 -0400 MIME-Version: 1.0 In-Reply-To: References: <1d3f23370910070013u6307bc42hf7ab243b52d007df@mail.gmail.com> Date: Thu, 8 Oct 2009 09:44:43 +1000 Message-ID: <1d3f23370910071644y5877cf9v879967340a463f19@mail.gmail.com> Subject: Re: Xilinx SYSACE driver and 8-bit attachment From: John Williams To: Grant Likely Cc: Linux Kernel list , Michal Simek , John Linn , David DeBonis , Stephen Neuendorffer , devicetree-discuss Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2028 Lines: 51 On Wed, Oct 7, 2009 at 11:34 PM, Grant Likely wrote: > [Added devicetree-discuss to cc: list] > > On Wed, Oct 7, 2009 at 1:13 AM, John Williams > wrote: >> Hi Grant (it's your driver :) and David D ( and your DTS generator :) > [...] >> if (of_find_property(op->node, "8-bit", NULL)) > [...] >> doesn't match the properties generated by Xilinx's device tree generator: > [...] >> ??????????????????????? xlnx,mem-width = <0x8>; >> >> So, the question is, which should change? > > Well, obviously its a device tree generator bug, the driver code is > perfect. ?:-P How did I know you'd say that? :) > In all seriousness though, the '8-bit' property has been present for a > while now and needs to be retained to not break existing users. ?It > would be okay for the driver to be modified to *also* check for the > xlnx,mem-width property, but the better solution is to modify the > device tree generator. ?Plus, the '8-bit' property is the documented > binding in Documentation/powerpc/dts-bindings/xilinx.txt I tend to agree - but I also tend think that putting funky, arbitrary output strings in the DTS generator is also a bad idea. In this case, my vote is leaning towards adding a test for "xlnx,mem-width = <..>" to the driver, in addition to the existing "8-bit" tag to keep back compatability. How would you feel about that? In future, for new Xilinx drivers I think the default binding should be inspired by what comes from the DTS generator automatically, with out any special per-device hacks. This has a natural tendency towards minimum pain I think. John -- John Williams, PhD, B.Eng, B.IT PetaLogix - Linux Solutions for a Reconfigurable World w: www.petalogix.com p: +61-7-30090663 f: +61-7-30090663 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/