From mboxrd@z Thu Jan 1 00:00:00 1970 From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi) Date: Wed, 19 Jun 2013 12:23:24 +0100 Subject: [PATCH] ARM: kernel: document ARM CPUs clock-frequency property In-Reply-To: References: <1371635237-22860-1-git-send-email-f.fainelli@gmail.com> <20130619100450.GA27181@e106331-lin.cambridge.arm.com> Message-ID: <20130619112324.GA32207@e102568-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.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