Sent from Anson's iPhone
> 在 2013年12月19日，22:21，"Sudeep KarkadaNagesha" <Sudeep.KarkadaNagesha@xxxxxxx> 写道：
>
>> On 19/12/13 14:16, Anson Huang wrote:
>> This device tree binding document describes the imx6 cpufreq
>> DT bindings. This document lists all required and optional properties
>> for imx6 cpufreq.
>>
>> Signed-off-by: Anson Huang <b20788@xxxxxxxxxxxxx>
>> ---
>> .../devicetree/bindings/cpufreq/cpufreq-imx6.txt | 56 ++++++++++++++++++++
>> 1 file changed, 56 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-imx6.txt
>>
>> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-imx6.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-imx6.txt
>> new file mode 100644
>> index 0000000..a14b895
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-imx6.txt
>> @@ -0,0 +1,56 @@
>> +i.MX6 cpufreq driver
>> +-------------------
>> +
>> +i.MX6 SoC cpufreq driver for CPU frequency scaling.
>> +
>> +This binding doc defines properties that must be put in the /cpus/cpu@0 node,
>> +please refer to Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt
>> +for detail.
>> +
>> +Required properties:
>> +- operating-points: Refer to Documentation/devicetree/bindings/power/opp.txt
>> + for details.
>> +- clocks: Specify clocks that need to be used when cpu frequency is scaled,
>> + refer to Documentation/devicetree/bindings/clock/clock-bindings.txt for
>> + details.
>> +- clock-names: List of clock input name strings sorted in the same order as the
>> + clocks property, refer to Documentation/devicetree/bindings/clock/clock-bindings.txt
>> + for details.
>> +- xxx-supply: Input voltage supply regulator, refer to
>> + Documentation/devicetree/bindings/regulator/regulator.txt for details.
>> + arm-supply: regulator node supplying arm.
>> + pu-supply: regulator node supplying pu.
>> + soc-supply: regulator node supplying soc.
>> +
>> +Optional properties:
>> +- fsl,soc-operating-points: Specify vddsoc/pu voltage settings that must
>> + go with cpu0's operating-points.
>> +- clock-latency: Specify the possible maximum transition latency for clock,
>> + in unit of nanoseconds.
>> +
>
> Sorry if I am missing something obvious as I have not followed the previous
> versions and corresponding comments.
>
> Should these SoC properties be part of cpu node ? If so which cpu or why cpu0 ?
yes, these properties are for cpufreq function, as on SMP system, all CPUs are running at same freq, cpufreq is tied to cpu0, so we put them in cpu0's node.
> IIUC it's more a SoC properties which also influences ARM CPU OPPs. IOW other
> regulators may depend on pu/soc-supply. In that case it would be cleaner if that
> dependency is setup through regulators framework.
the truth is that arm power domain has no level shift with sic/pu domain, so when arm domain voltage is changed, soc/pu domain need to be changed too, more like multi OPP concept. there is no other regulators depend on soc/pu supply.
anson.
>
>> +Examples:
>> +
>> + cpu@0 {
>> + operating-points = <
>> + /* kHz uV */
>> + 1200000 1275000
>> + 996000 1250000
>> + 792000 1150000
>> + 396000 975000
>> + >;
>> + fsl,soc-operating-points = <
>> + /* ARM kHz SOC-PU uV */
>> + 1200000 1275000
>> + 996000 1250000
>> + 792000 1175000
>> + 396000 1175000
>> + >;
>> + clock-latency = <61036>; /* two CLK32 periods */
>> + clocks = <&clks 104>, <&clks 6>, <&clks 16>,
>> + <&clks 17>, <&clks 170>;
>> + clock-names = "arm", "pll2_pfd2_396m", "step",
>> + "pll1_sw", "pll1_sys";
>> + arm-supply = <®_arm>;
>> + pu-supply = <®_pu>;
>> + soc-supply = <®_soc>;
>> + };
>
>
>
>
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