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Diffstat (limited to 'Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt new file mode 100644 index 000000000..6b0b452ac --- /dev/null +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt @@ -0,0 +1,89 @@ +Binding for ST's CPUFreq driver +=============================== + +ST's CPUFreq driver attempts to read 'process' and 'version' attributes +from the SoC, then supplies the OPP framework with 'prop' and 'supported +hardware' information respectively. The framework is then able to read +the DT and operate in the usual way. + +Frequency Scaling only +---------------------- + +No vendor specific driver required for this. + +Located in CPU's node: + +- operating-points : [See: ../power/opp-v1.yaml] + +Example [safe] +-------------- + +cpus { + cpu@0 { + /* kHz uV */ + operating-points = <1500000 0 + 1200000 0 + 800000 0 + 500000 0>; + }; +}; + +Dynamic Voltage and Frequency Scaling (DVFS) +-------------------------------------------- + +This requires the ST CPUFreq driver to supply 'process' and 'version' info. + +Located in CPU's node: + +- operating-points-v2 : [See ../power/opp-v2.yaml] + +Example [unsafe] +---------------- + +cpus { + cpu@0 { + operating-points-v2 = <&cpu0_opp_table>; + }; +}; + +cpu0_opp_table: opp_table { + compatible = "operating-points-v2"; + + /* ############################################################### */ + /* # WARNING: Do not attempt to copy/replicate these nodes, # */ + /* # they are only to be supplied by the bootloader !!! # */ + /* ############################################################### */ + opp0 { + /* Major Minor Substrate */ + /* 2 all all */ + opp-supported-hw = <0x00000004 0xffffffff 0xffffffff>; + opp-hz = /bits/ 64 <1500000000>; + clock-latency-ns = <10000000>; + + opp-microvolt-pcode0 = <1200000>; + opp-microvolt-pcode1 = <1200000>; + opp-microvolt-pcode2 = <1200000>; + opp-microvolt-pcode3 = <1200000>; + opp-microvolt-pcode4 = <1170000>; + opp-microvolt-pcode5 = <1140000>; + opp-microvolt-pcode6 = <1100000>; + opp-microvolt-pcode7 = <1070000>; + }; + + opp1 { + /* Major Minor Substrate */ + /* all all all */ + opp-supported-hw = <0xffffffff 0xffffffff 0xffffffff>; + opp-hz = /bits/ 64 <1200000000>; + clock-latency-ns = <10000000>; + + opp-microvolt-pcode0 = <1110000>; + opp-microvolt-pcode1 = <1150000>; + opp-microvolt-pcode2 = <1100000>; + opp-microvolt-pcode3 = <1080000>; + opp-microvolt-pcode4 = <1040000>; + opp-microvolt-pcode5 = <1020000>; + opp-microvolt-pcode6 = <980000>; + opp-microvolt-pcode7 = <930000>; + }; +}; |