From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Rutland Subject: Re: [PATCH v6 2/2] Documentation: devicetree: Add boost-frequency binding to list boost mode frequency Date: Fri, 30 May 2014 14:08:27 +0100 Message-ID: <20140530130827.GK24233@leverpostej> References: <1401440477-4328-1-git-send-email-thomas.ab@samsung.com> <1401440477-4328-3-git-send-email-thomas.ab@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1401440477-4328-3-git-send-email-thomas.ab@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Thomas Abraham Cc: "linux-pm@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "rjw@rjwysocki.net" , "linux-samsung-soc@vger.kernel.org" , "kgene.kim@samsung.com" , "t.figa@samsung.com" , "l.majewski@samsung.com" , "viresh.kumar@linaro.org" , "nm@ti.com" , Rob Herring , Pawel Moll , Ian Campbell , Kumar Gala List-Id: linux-pm@vger.kernel.org Hi, Apologies for being somewhat late w.r.t. review on this. On Fri, May 30, 2014 at 10:01:17AM +0100, Thomas Abraham wrote: > From: Thomas Abraham > > Add a new optional boost-frequency binding for specifying the frequencies > usable in boost mode. > > Cc: Rob Herring > Cc: Pawel Moll > Cc: Mark Rutland > Cc: Ian Campbell > Cc: Kumar Gala > Signed-off-by: Thomas Abraham > Acked-by: Viresh Kumar > Acked-by: Nishanth Menon > Acked-by: Lukasz Majewski > --- > .../devicetree/bindings/cpufreq/cpufreq-boost.txt | 38 ++++++++++++++++++++ > 1 file changed, 38 insertions(+) > create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-boost.txt > > diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-boost.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-boost.txt > new file mode 100644 > index 0000000..63ed0fc > --- /dev/null > +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-boost.txt > @@ -0,0 +1,38 @@ > +* Device tree binding for CPU boost frequency (aka over-clocking) > + > +Certain CPU's can be operated in optional 'boost' mode (or sometimes referred as Nit: CPUs (we're not greengrocers [1]) > +overclocking) in which the CPU can operate at frequencies which are not > +specified by the manufacturer as CPU's operating frequency. > + > +Optional Properties: > +- boost-frequencies: list of frequencies in KHz to be used only in boost mode. > + This list should be a subset of frequencies listed in "operating-points" > + property. Refer to Documentation/devicetree/bindings/power/opp.txt for > + details about "operating-points" property. What is 'boost-mode'? What are the limitations on boost frequencies? When is a CPU expected to go to these frequencies and for now long? When should I as a dt author place elements in boost-frequencies? Why are these in both operating-points and boost-frequencies? It'll be really easy to accidentally forget to mark something as a boost-frequency this way. Why not have a boost-points instead? > + > +Example: > + > + cpus { > + #address-cells = <1>; > + #size-cells = <0>; > + cpu@0 { > + device_type = "cpu"; > + compatible = "arm,cortex-a9"; > + reg = <0>; > + > + operating-points = < > + 1500000 1350000 > + 1400000 1287500 > + 1300000 1250000 > + 1200000 1187500 > + 1100000 1137500 > + 1000000 1087500 > + >; > + boost-frequencies = <1500000 1400000>; This is more of a general issue, but I hate the whole cpufreq-cpu0 way of assuming that all CPUs mirror CPU0. It would be nicer if either this were dropped in /cpus or repeated per-cpu. Cheers, Mark. > + }; > + cpu@1 { > + device_type = "cpu"; > + compatible = "arm,cortex-a9"; > + reg = <1>; > + }; > + }; > -- > 1.7.9.5 > > [1] http://en.wikipedia.org/wiki/Apostrophe#Superfluous_apostrophes_.28.22greengrocers.27_apostrophes.22.29 From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Fri, 30 May 2014 14:08:27 +0100 Subject: [PATCH v6 2/2] Documentation: devicetree: Add boost-frequency binding to list boost mode frequency In-Reply-To: <1401440477-4328-3-git-send-email-thomas.ab@samsung.com> References: <1401440477-4328-1-git-send-email-thomas.ab@samsung.com> <1401440477-4328-3-git-send-email-thomas.ab@samsung.com> Message-ID: <20140530130827.GK24233@leverpostej> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Apologies for being somewhat late w.r.t. review on this. On Fri, May 30, 2014 at 10:01:17AM +0100, Thomas Abraham wrote: > From: Thomas Abraham > > Add a new optional boost-frequency binding for specifying the frequencies > usable in boost mode. > > Cc: Rob Herring > Cc: Pawel Moll > Cc: Mark Rutland > Cc: Ian Campbell > Cc: Kumar Gala > Signed-off-by: Thomas Abraham > Acked-by: Viresh Kumar > Acked-by: Nishanth Menon > Acked-by: Lukasz Majewski > --- > .../devicetree/bindings/cpufreq/cpufreq-boost.txt | 38 ++++++++++++++++++++ > 1 file changed, 38 insertions(+) > create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-boost.txt > > diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-boost.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-boost.txt > new file mode 100644 > index 0000000..63ed0fc > --- /dev/null > +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-boost.txt > @@ -0,0 +1,38 @@ > +* Device tree binding for CPU boost frequency (aka over-clocking) > + > +Certain CPU's can be operated in optional 'boost' mode (or sometimes referred as Nit: CPUs (we're not greengrocers [1]) > +overclocking) in which the CPU can operate at frequencies which are not > +specified by the manufacturer as CPU's operating frequency. > + > +Optional Properties: > +- boost-frequencies: list of frequencies in KHz to be used only in boost mode. > + This list should be a subset of frequencies listed in "operating-points" > + property. Refer to Documentation/devicetree/bindings/power/opp.txt for > + details about "operating-points" property. What is 'boost-mode'? What are the limitations on boost frequencies? When is a CPU expected to go to these frequencies and for now long? When should I as a dt author place elements in boost-frequencies? Why are these in both operating-points and boost-frequencies? It'll be really easy to accidentally forget to mark something as a boost-frequency this way. Why not have a boost-points instead? > + > +Example: > + > + cpus { > + #address-cells = <1>; > + #size-cells = <0>; > + cpu at 0 { > + device_type = "cpu"; > + compatible = "arm,cortex-a9"; > + reg = <0>; > + > + operating-points = < > + 1500000 1350000 > + 1400000 1287500 > + 1300000 1250000 > + 1200000 1187500 > + 1100000 1137500 > + 1000000 1087500 > + >; > + boost-frequencies = <1500000 1400000>; This is more of a general issue, but I hate the whole cpufreq-cpu0 way of assuming that all CPUs mirror CPU0. It would be nicer if either this were dropped in /cpus or repeated per-cpu. Cheers, Mark. > + }; > + cpu at 1 { > + device_type = "cpu"; > + compatible = "arm,cortex-a9"; > + reg = <1>; > + }; > + }; > -- > 1.7.9.5 > > [1] http://en.wikipedia.org/wiki/Apostrophe#Superfluous_apostrophes_.28.22greengrocers.27_apostrophes.22.29