From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754335AbaHFWYm (ORCPT ); Wed, 6 Aug 2014 18:24:42 -0400 Received: from mail-vc0-f175.google.com ([209.85.220.175]:58539 "EHLO mail-vc0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753151AbaHFWYd (ORCPT ); Wed, 6 Aug 2014 18:24:33 -0400 MIME-Version: 1.0 In-Reply-To: References: <1403220823-19444-1-git-send-email-f.fainelli@gmail.com> <20140806165452.GN3711@ld-irv-0074> <20140806201256.GO3711@ld-irv-0074> From: Rob Herring Date: Wed, 6 Aug 2014 17:24:12 -0500 Message-ID: Subject: Re: [PATCH] of/irq: lookup 'interrupts-extended' property first To: Tim Bird Cc: Brian Norris , Florian Fainelli , "devicetree@vger.kernel.org" , Grant Likely , Rob Herring , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 6, 2014 at 4:50 PM, Tim Bird wrote: > On Wed, Aug 6, 2014 at 1:12 PM, Brian Norris > wrote: >> On Wed, Aug 06, 2014 at 01:42:08PM -0500, Rob Herring wrote: >>> On Wed, Aug 6, 2014 at 11:54 AM, Brian Norris wrote: >>> > On Thu, Jul 31, 2014 at 11:00:01AM -0700, Florian Fainelli wrote: >>> > I think it is important that a device tree provide some flexibility on >>> > kernel versions. We only invented 'interrupts-extended' in Linux 3.13, >>> > so it's easy to have device trees that could work only on 3.13+. >>> > >>> > Typically, we might say that new features require new kernels, but this >>> > is a very basic piece of the DT infrastructure. In our case, we have >>> > hardware whose basic features can be supported by a single interrupt >>> > parent, and so we used the 'interrupts' property pre-3.13. But when we >>> > want to add some power management features, there's an additional >>> > interrupt parent. Under the current DT binding, we have to switch over >>> > to using 'interrupts-extended' exclusively, and thus we must have a >>> > completely new DTB for >=3.13, and this DTB no longer works with the old >>> > kernels. >>> >>> "Must have" to enable the new features? >> >> Yes. The new feature requires an additional interrupt parent, and so it >> requires interrupts-extended. > > Hold on there. What about interrupt-map? That was the traditional DT > feature for > supporting multi-parented interrupts. Why couldn't the feature have been added > using that instead of interrupts-extended? It could have, but interrupts-extended is much more simple to express for the simple case of a device's interrupts routed to more than one parent. > I know interrupts-extended is preferred, but has interrupt-map support been > removed from recent kernels? I'm a bit confused. They are all still supported. It's just a question of order of parsing if you have find both styles. Rob