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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
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Binding for ST's CPUFreq driver

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===============================

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ST's CPUFreq driver attempts to read 'process' and 'version' attributes

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from the SoC, then supplies the OPP framework with 'prop' and 'supported

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hardware' information respectively.  The framework is then able to read

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the DT and operate in the usual way.

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Frequency Scaling only

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----------------------

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No vendor specific driver required for this.

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Located in CPU's node:

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- operating-points		: [See: ../power/opp-v1.yaml]

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Example [safe]

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--------------

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cpus {

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	cpu@0 {

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				 /* kHz     uV   */

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		operating-points = <1500000 0

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				    1200000 0

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				    800000  0

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				    500000  0>;

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	};

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};

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Dynamic Voltage and Frequency Scaling (DVFS)

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--------------------------------------------

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This requires the ST CPUFreq driver to supply 'process' and 'version' info.

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Located in CPU's node:

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- operating-points-v2		: [See ../power/opp-v2.yaml]

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Example [unsafe]

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----------------

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cpus {

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	cpu@0 {

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		operating-points-v2	= <&cpu0_opp_table>;

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	};

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};

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cpu0_opp_table: opp_table {

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	compatible = "operating-points-v2";

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	/* ############################################################### */

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	/* # WARNING: Do not attempt to copy/replicate these nodes,      # */

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	/* #          they are only to be supplied by the bootloader !!! # */

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	/* ############################################################### */

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	opp0 {

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		/*			   Major       Minor       Substrate */

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		/*			   2           all         all       */

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		opp-supported-hw	= <0x00000004  0xffffffff  0xffffffff>;

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		opp-hz			= /bits/ 64 <1500000000>;

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		clock-latency-ns	= <10000000>;

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		opp-microvolt-pcode0	= <1200000>;

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		opp-microvolt-pcode1	= <1200000>;

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		opp-microvolt-pcode2	= <1200000>;

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		opp-microvolt-pcode3	= <1200000>;

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		opp-microvolt-pcode4	= <1170000>;

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		opp-microvolt-pcode5	= <1140000>;

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		opp-microvolt-pcode6	= <1100000>;

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		opp-microvolt-pcode7	= <1070000>;

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	};

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	opp1 {

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		/*			   Major       Minor       Substrate */

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		/*			   all         all         all       */

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		opp-supported-hw	= <0xffffffff  0xffffffff  0xffffffff>;

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		opp-hz			= /bits/ 64 <1200000000>;

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		clock-latency-ns	= <10000000>;

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		opp-microvolt-pcode0	= <1110000>;

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		opp-microvolt-pcode1	= <1150000>;

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		opp-microvolt-pcode2	= <1100000>;

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		opp-microvolt-pcode3	= <1080000>;

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		opp-microvolt-pcode4	= <1040000>;

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		opp-microvolt-pcode5	= <1020000>;

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		opp-microvolt-pcode6	= <980000>;

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		opp-microvolt-pcode7	= <930000>;

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	};

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};

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