Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752069AbaAPSdf (ORCPT ); Thu, 16 Jan 2014 13:33:35 -0500 Received: from service87.mimecast.com ([91.220.42.44]:55119 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751700AbaAPSdb convert rfc822-to-8bit (ORCPT ); Thu, 16 Jan 2014 13:33:31 -0500 Date: Thu, 16 Jan 2014 18:33:26 +0000 From: Lorenzo Pieralisi To: Stephen Boyd Cc: Borislav Petkov , "linux-kernel@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-edac@vger.kernel.org" , Mark Rutland , Kumar Gala , "devicetree@vger.kernel.org" Subject: Re: [PATCH v5 2/4] devicetree: bindings: Document Krait CPU/L1 EDAC Message-ID: <20140116183326.GG25540@e102568-lin.cambridge.arm.com> References: <1389735034-21430-1-git-send-email-sboyd@codeaurora.org> <1389735034-21430-3-git-send-email-sboyd@codeaurora.org> <20140115102701.GA27314@e102568-lin.cambridge.arm.com> <20140115165623.GJ14405@codeaurora.org> <20140116013840.GA674@codeaurora.org> <20140116113332.GC25540@e102568-lin.cambridge.arm.com> <20140116180505.GA30925@codeaurora.org> MIME-Version: 1.0 In-Reply-To: <20140116180505.GA30925@codeaurora.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-OriginalArrivalTime: 16 Jan 2014 18:33:27.0336 (UTC) FILETIME=[726B7A80:01CF12E9] X-MC-Unique: 114011618332902801 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 16, 2014 at 06:05:05PM +0000, Stephen Boyd wrote: > On 01/16, Lorenzo Pieralisi wrote: > > On Thu, Jan 16, 2014 at 01:38:40AM +0000, Stephen Boyd wrote: > > > On 01/15, Stephen Boyd wrote: > > > > > > > > Ah sorry, I forgot to put the compatible property here like in > > > > the dts change. I'll do that in the next revision. Yes we need a > > > > compatible property here to match the platform driver. > > > > > > > > > > This is the replacement patch > > > > > > -----8<------ > > > From: Stephen Boyd > > > Subject: [PATCH v9] devicetree: bindings: Document Krait CPU/L1 EDAC > > > > > > The Krait CPU/L1 error reporting device is made up a per-CPU > > > interrupt. While we're here, document the next-level-cache > > > property that's used by the Krait EDAC driver. > > > > > > Cc: Lorenzo Pieralisi > > > Cc: Mark Rutland > > > Cc: Kumar Gala > > > Cc: > > > Signed-off-by: Stephen Boyd > > > --- > > > Documentation/devicetree/bindings/arm/cpus.txt | 58 ++++++++++++++++++++++++++ > > > 1 file changed, 58 insertions(+) > > > > > > diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt > > > index 91304353eea4..03a529e791c4 100644 > > > --- a/Documentation/devicetree/bindings/arm/cpus.txt > > > +++ b/Documentation/devicetree/bindings/arm/cpus.txt > > > @@ -62,6 +62,20 @@ nodes to be present and contain the properties described below. > > > Value type: > > > Definition: must be set to 0 > > > > > > + - compatible > > > + Usage: optional > > > + Value type: > > > + Definition: should be one of the compatible strings listed > > > + in the cpu node compatible property. This property > > > + shall only be present if all the cpu nodes have the > > > + same compatible property. > > > > Do we really want to do that ? I am not sure. A cpus node is supposed to > > be a container node, we should not define this binding just because we > > know the kernel creates a platform device for it then. > > This is just copying more of the ePAPR spec into this document. > It just so happens that having a compatible field here allows a > platform device to be created. I don't see why that's a problem. I do not see why you cannot define a node like pmu or arch-timer and stick a compatible property in there. cpus node does not represent a device, and must not be created as a platform device, that's my opinion. What would you do for big.LITTLE systems ? We are going to create two cpus node because we need two platform devices ? I really think there must be a better way to implement this, but I will let DT maintainers make a decision. > > interrupts is a cpu node property and I think it should be kept as such. > > > > I know it will be duplicated and I know you can't rely on a platform > > device for probing (since if I am not mistaken, removing a compatible > > string from cpus prevents its platform device creation), but that's an issue > > related to how the kernel works, you should not define DT bindings to solve > > that IMHO. > > The interrupts property is also common for all cpus so it seems > fine to collapse the value down into a PPI specifier indicating > that all CPUs get the interrupt, similar to how we compress the > information about the compatible string. I think it is nicer to create a device node (as I said, like a pmu or an arch-timer) and define interrupts there along with a proper compatible property. This would serve the same purpose without adding properties in the cpus node. cpu-edac { compatible = "qcom,cpu-edac"; interrupts = <...>; }; Thanks, Lorenzo -- 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/