Re: [PATCH 1/2] dt-bindings: mediatek: Add MT8173 cpufreq driver binding

[Pi-Cheng Chen <pi-cheng.chen@linaro.org>]

On Wed, Jun 24, 2015 at 9:06 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> Adding Mike's new email address..
>
> On 23-06-15, 23:31, Pi-Cheng Chen wrote:
>> On Mon, Jun 8, 2015 at 8:29 PM, Pi-Cheng Chen <pi-cheng.chen@linaro.org> wrote:
>> > This patch adds device tree binding document for MT8173 cpufreq driver.
>> >
>> > Signed-off-by: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
>> > ---
>> >  .../devicetree/bindings/cpufreq/cpufreq-mt8173.txt | 127 +++++++++++++++++++++
>> >  1 file changed, 127 insertions(+)
>> >  create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-mt8173.txt
>> >
>> > diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-mt8173.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-mt8173.txt
>> > new file mode 100644
>> > index 0000000..7708a65
>> > --- /dev/null
>> > +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-mt8173.txt
>> > @@ -0,0 +1,127 @@
>> > +
>> > +Mediatek MT8173 cpufreq driver
>> > +-------------------
>
> Few more ---- required.

Will add it.

>
>> > +
>> > +Mediatek MT8173 cpufreq driver for CPU frequency scaling.
>> > +
>> > +Required properties:
>> > +- clocks: A list of phandle + clock-specifier pairs for the clocks listed in clock names.
>> > +- clock-names: Should contain the following:
>> > +       "cpu"           - The multiplexer for clock input of CPU cluster.
>> > +       "intermediate"  - A parent of "cpu" clock which is used as "intermediate" clock
>> > +                         source (usually MAINPLL) when the original CPU PLL is under
>> > +                         transition and not stable yet.
>
> These belong to Mike.
>
>> > +- operating-points: Table of frequencies and voltage CPU could be transitioned into,
>> > +                   Frequency should be in KHz units and voltage should be in microvolts.
>
> That's not complete. You should just mention the path to opp bindings
> here. And that's it.

Yes. So should it be:
- operating-points: Refer to
Documentation/devicetree/bindings/power/opp.txt
  for details

?

>
>> > +- proc-supply: Regulator for Vproc of CPU cluster.
>> > +
>> > +Optional properties:
>> > +- sram-supply: Regulator for Vsram of CPU cluster. When present, the cpufreq driver
>> > +              needs to do "voltage trace" to step by step scale up/down Vproc and
>> > +              Vsram to fit SoC specific needs. When absent, the voltage scaling
>> > +              flow is handled by hardware, hence no software "voltage trace" is
>> > +              needed.
>> > +
>> > +Example:
>> > +--------
>> > +       cpu0: cpu@0 {
>> > +               device_type = "cpu";
>> > +               compatible = "arm,cortex-a53";
>> > +               reg = <0x000>;
>> > +               enable-method = "psci";
>> > +               cpu-idle-states = <&CPU_SLEEP_0>;
>> > +               clocks = <&infracfg CLK_INFRA_CA53SEL>,
>> > +                        <&apmixedsys CLK_APMIXED_MAINPLL>;
>> > +               clock-names = "cpu", "intermediate";
>> > +               operating-points = <
>> > +                       507000  859000
>> > +                       702000  908000
>> > +                       1001000 983000
>> > +                       1105000 1009000
>> > +                       1183000 1028000
>> > +                       1404000 1083000
>> > +                       1508000 1109000
>> > +                       1573000 1125000
>> > +               >;
>> > +       };
>> > +
>> > +       cpu1: cpu@1 {
>> > +               device_type = "cpu";
>> > +               compatible = "arm,cortex-a53";
>> > +               reg = <0x001>;
>> > +               enable-method = "psci";
>> > +               cpu-idle-states = <&CPU_SLEEP_0>;
>> > +               clocks = <&infracfg CLK_INFRA_CA53SEL>,
>> > +                        <&apmixedsys CLK_APMIXED_MAINPLL>;
>> > +               clock-names = "cpu", "intermediate";
>> > +               operating-points = <
>> > +                       507000  859000
>> > +                       702000  908000
>> > +                       1001000 983000
>> > +                       1105000 1009000
>> > +                       1183000 1028000
>> > +                       1404000 1083000
>> > +                       1508000 1109000
>> > +                       1573000 1125000
>> > +               >;
>> > +       };
>> > +
>> > +       cpu2: cpu@100 {
>> > +               device_type = "cpu";
>> > +               compatible = "arm,cortex-a57";
>> > +               reg = <0x100>;
>> > +               enable-method = "psci";
>> > +               cpu-idle-states = <&CPU_SLEEP_0>;
>> > +               clocks = <&infracfg CLK_INFRA_CA57SEL>,
>> > +                        <&apmixedsys CLK_APMIXED_MAINPLL>;
>> > +               clock-names = "cpu", "intermediate";
>> > +               operating-points = <
>> > +                       507000  828000
>> > +                       702000  867000
>> > +                       1001000 927000
>> > +                       1209000 968000
>> > +                       1404000 1007000
>> > +                       1612000 1049000
>> > +                       1807000 1089000
>> > +                       1989000 1125000
>> > +               >;
>> > +       };
>> > +
>> > +       cpu3: cpu@101 {
>> > +               device_type = "cpu";
>> > +               compatible = "arm,cortex-a57";
>> > +               reg = <0x101>;
>> > +               enable-method = "psci";
>> > +               cpu-idle-states = <&CPU_SLEEP_0>;
>> > +               clocks = <&infracfg CLK_INFRA_CA57SEL>,
>> > +                        <&apmixedsys CLK_APMIXED_MAINPLL>;
>> > +               clock-names = "cpu", "intermediate";
>> > +               operating-points = <
>> > +                       507000  828000
>> > +                       702000  867000
>> > +                       1001000 927000
>> > +                       1209000 968000
>> > +                       1404000 1007000
>> > +                       1612000 1049000
>> > +                       1807000 1089000
>> > +                       1989000 1125000
>> > +               >;
>> > +       };
>
> I remember Mark Rutland asking you about the replicated stuff for all
> CPUs, but happened to his comments later on ? Were you asked to put
> these for all the CPUs ?

I was not asked to do so and I didn't get any further comments for last
series from then. But I think duplicating these properties for all CPU nodes
helps in the cases all CPUs in a cluster are unplugged and plugged in different
order and it's more properly descriptive for the real hardware. Therefore I
replicate them for all CPUs.

Thanks for your reviewing.

Pi-Cheng

>
> --
> viresh