From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751291AbdEaRNY (ORCPT ); Wed, 31 May 2017 13:13:24 -0400 Received: from foss.arm.com ([217.140.101.70]:47092 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198AbdEaRMM (ORCPT ); Wed, 31 May 2017 13:12:12 -0400 Cc: Sudeep Holla , Jassi Brar , Linux Kernel Mailing List , Devicetree List , Alexey Klimov , Jassi Brar Subject: Re: [PATCH v2 2/6] Documentation: devicetree: add bindings to support ARM MHU doorbells To: Rob Herring References: <1495621003-4291-1-git-send-email-sudeep.holla@arm.com> <1495621003-4291-3-git-send-email-sudeep.holla@arm.com> <20170531170801.u6d4fhsfu5mmqgta@rob-hp-laptop> From: Sudeep Holla Organization: ARM Message-ID: Date: Wed, 31 May 2017 18:12:08 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <20170531170801.u6d4fhsfu5mmqgta@rob-hp-laptop> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 31/05/17 18:08, Rob Herring wrote: > On Thu, May 25, 2017 at 02:23:44PM +0100, Sudeep Holla wrote: >> >> >> On 25/05/17 14:22, Jassi Brar wrote: [...] >>> Every MHU controller can by driven as "arm,mhu-doorbell" or "arm,mhu" >>> equally fine. So you are basically smuggling a s/w feature into DT. >>> >> >> I disagree, the spec clearly says each bit can be used for different >> event and hence we need a way to specify that in DT when used as doorbell. > > I think the point is that you should not continue to use both. The > single cell usage should be deprecated. Maybe you'll have to encode the > 2nd cell when not used as 0 means bit 0? > Instead of having special encoding, I like your below suggestion on using #mbox-cells to distinguish the usage modes. > Arguably, you don't even need a new compatible. #mbox-cells tells you > whether to use the old or new binding. I'm fine either way though. > Ah good point, yes we can distinguish with #mbox-cells. I will drop the new compatible. -- Regards, Sudeep