From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH] ARM: kernel: document ARM CPUs clock-frequency property Date: Wed, 19 Jun 2013 12:23:24 +0100 Message-ID: <20130619112324.GA32207@e102568-lin.cambridge.arm.com> References: <1371635237-22860-1-git-send-email-f.fainelli@gmail.com> <20130619100450.GA27181@e106331-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Florian Fainelli Cc: "nico-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , "rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org" , "grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org On Wed, Jun 19, 2013 at 11:27:50AM +0100, Florian Fainelli wrote: > Hello Mark, > > 2013/6/19 Mark Rutland : > > On Wed, Jun 19, 2013 at 10:47:17AM +0100, Florian Fainelli wrote: > >> ARM CPU device tree nodes may contain an optional clock-frequency > >> property, when set, this property must contain the CPU frequency in Hz, > >> which is then used by the topology parsing code in > >> arch/arm/kernel/topology.c to infer the CPU capacity. > > > > I see that arch/arm/kernel/topology.c does a pr_err when clock-frequency isn't > > present. If we're documenting it as optional, should we not downgrade that or > > remove it entirely? > > Good question. I think it might be good to just dowgrade the error to > a simple warning, we should clearly be fixing the binding if we have a > device_type = "cpu" property but no clock-frequency property. Well, this means that that pr_err will trigger as soon as the dts updates hit the mainline, now probably it is silent because cpu nodes for architectures with "arm,cortex-a15" as cpus miss device_type = "cpu". ePAPR defines "clock-frequency" as required. So either we downgrade it to optional or we are in for another slew of dts updates, I am really looking forward to that. Certainly it has to be added to the bindings. Thoughts ? Lorenzo