91 lines
4.2 KiB
Plaintext
91 lines
4.2 KiB
Plaintext
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Binding for Rockchip's CPUFreq driver
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===============================
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Rockchip's CPUFreq driver attempts to read leakage value from eFuse
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and get frequency count from pvtm, then supplies the OPP framework
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with 'prop' information which is used to determine opp-microvolt-<name>
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property of OPPS when it is parsed by the OPP framework. This is based
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on operating-points-v2, but the driver can also create the "cpufreq-dt"
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platform_device to compatibility with operating-points.
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For more information about the expected DT format [See: ../opp/opp.txt].
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Optional properties:
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In 'operating-points-v2' table:
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- rockchip,leakage-voltage-sel: The property is an array of 3-tuples items, and
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each item consists of leakage and voltage selector like
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<min-leakage max-leakage volt-selector>.
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min-leakage: minimum leakage in mA, ranges from 1 to 254.
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max-leakage: maximum leakage in mA, ranges from 1 to 254.
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voltage-selector: a sequence number which is used to math
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opp-microvolt-L<number> roperty in OPP node.
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- rockchip,pvtm-voltage-sel: The property is an array of 3-tuples items, and
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each item consists of pvtm and voltage selector like
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<min-pvtm max-pvtm volt-selector>.
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min-pvtm: minimum frequency count in KHz.
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max-pvtm: maximum frequency count in KHz.
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voltage-selector: a sequence number which is used to math
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opp-microvolt-L<number> roperty in OPP node.
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- rockchip,pvtm-freq: Clock frequency in KHz, which is used to set the cpu clock
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frequency before get frequency count of pvtm.
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- rockchip,pvtm-volt: Voltage in uV, which is used to set the cpu voltage before
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get frequency count of pvtm.
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- rockchip,pvtm-ch: An array of two integers containing pvtm channel and clock
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oscillation ring.
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- rockchip,pvtm-sample-time: The number of milliseconds to wait for pvtm to
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finish counting.
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- rockchip,pvtm-number: An integer indicating the number of sampling points.
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- rockchip,pvtm-error: An integer indicating the error between the sample
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results.
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- rockchip,pvtm-ref-temp: The SoC internal temperature in degree centigrade, the
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min-pvtm and max-pvtm in 'leakage-voltage-sel' are
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measured at reference temperature.
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- rockchip,pvtm-temp-prop: An array of two integers containing proportional
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constants which is used to convert the value at current
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temperature to reference temperature. The first one is
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used when current temperature is below reference
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temperature. Conversely, The second one is used when
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current temperature is above reference temperature.
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- rockchip,pvtm-thermal-zone: A thermal zone node containing thermal sensor,
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it's used to get the current temperature.
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- rockchip,thermal-zone: A thermal zone node containing thermal sensor,
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it's used to get the current temperature.
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- nvmem-cells: A phandle to cpu_leakage data provided by a nvmem device.
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- nvmem-cell-names: Should be "cpu_leakage"
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- rockchip,threshold-freq: Clock frequency in KHz, it's used to reduce power
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for SoCs with two clusters.
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- rockchip,freq-limit: Only one cluster can contain the property, and the
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cluster's maximum frequency will be limited to its
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threshold frequency, if the other cluster's frequency
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is geater than or equal to its threshold frequency.
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Examples:
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cpus {
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cpu@0 {
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operating-points-v2 = <&cluster0_opp>;
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};
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}
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cluster0_opp: opp_table0 {
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compatible = "operating-points-v2";
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opp-shared;
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rockchip,leakage-voltage-sel = <
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1 24 0
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25 254 1
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>;
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nvmem-cells = <&cpu_leakage>;
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nvmem-cell-names = "cpu_leakage";
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opp@216000000 {
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opp-hz = /bits/ 64 <216000000>;
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opp-microvolt = <950000 950000 1350000>;
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opp-microvolt-L0 = <1050000 1050000 1350000>;
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opp-microvolt-L1 = <950000 950000 1350000>;
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opp-suspend;
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}
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};
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