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| -rw-r--r-- | Documentation/devicetree/bindings/cpufreq/ti-cpufreq.txt | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/cpufreq/ti-cpufreq.txt b/Documentation/devicetree/bindings/cpufreq/ti-cpufreq.txt new file mode 100644 index 000000000..175805179 --- /dev/null +++ b/Documentation/devicetree/bindings/cpufreq/ti-cpufreq.txt @@ -0,0 +1,132 @@ +TI CPUFreq and OPP bindings +================================ + +Certain TI SoCs, like those in the am335x, am437x, am57xx, and dra7xx +families support different OPPs depending on the silicon variant in use. +The ti-cpufreq driver can use revision and an efuse value from the SoC to +provide the OPP framework with supported hardware information. This is +used to determine which OPPs from the operating-points-v2 table get enabled +when it is parsed by the OPP framework. + +Required properties: +-------------------- +In 'cpus' nodes: +- operating-points-v2: Phandle to the operating-points-v2 table to use. + +In 'operating-points-v2' table: +- compatible: Should be + - 'operating-points-v2-ti-cpu' for am335x, am43xx, and dra7xx/am57xx, + omap34xx, omap36xx and am3517 SoCs +- syscon: A phandle pointing to a syscon node representing the control module + register space of the SoC. + +Optional properties: +-------------------- +- "vdd-supply", "vbb-supply": to define two regulators for dra7xx +- "cpu0-supply", "vbb-supply": to define two regulators for omap36xx + +For each opp entry in 'operating-points-v2' table: +- opp-supported-hw: Two bitfields indicating: + 1. Which revision of the SoC the OPP is supported by + 2. Which eFuse bits indicate this OPP is available + + A bitwise AND is performed against these values and if any bit + matches, the OPP gets enabled. + +Example: +-------- + +/* From arch/arm/boot/dts/am33xx.dtsi */ +cpus { + #address-cells = <1>; + #size-cells = <0>; + cpu@0 { + compatible = "arm,cortex-a8"; + device_type = "cpu"; + reg = <0>; + + operating-points-v2 = <&cpu0_opp_table>; + + clocks = <&dpll_mpu_ck>; + clock-names = "cpu"; + + clock-latency = <300000>; /* From omap-cpufreq driver */ + }; +}; + +/* + * cpu0 has different OPPs depending on SoC revision and some on revisions + * 0x2 and 0x4 have eFuse bits that indicate if they are available or not + */ +cpu0_opp_table: opp-table { + compatible = "operating-points-v2-ti-cpu"; + syscon = <&scm_conf>; + + /* + * The three following nodes are marked with opp-suspend + * because they can not be enabled simultaneously on a + * single SoC. + */ + opp50-300000000 { + opp-hz = /bits/ 64 <300000000>; + opp-microvolt = <950000 931000 969000>; + opp-supported-hw = <0x06 0x0010>; + opp-suspend; + }; + + opp100-275000000 { + opp-hz = /bits/ 64 <275000000>; + opp-microvolt = <1100000 1078000 1122000>; + opp-supported-hw = <0x01 0x00FF>; + opp-suspend; + }; + + opp100-300000000 { + opp-hz = /bits/ 64 <300000000>; + opp-microvolt = <1100000 1078000 1122000>; + opp-supported-hw = <0x06 0x0020>; + opp-suspend; + }; + + opp100-500000000 { + opp-hz = /bits/ 64 <500000000>; + opp-microvolt = <1100000 1078000 1122000>; + opp-supported-hw = <0x01 0xFFFF>; + }; + + opp100-600000000 { + opp-hz = /bits/ 64 <600000000>; + opp-microvolt = <1100000 1078000 1122000>; + opp-supported-hw = <0x06 0x0040>; + }; + + opp120-600000000 { + opp-hz = /bits/ 64 <600000000>; + opp-microvolt = <1200000 1176000 1224000>; + opp-supported-hw = <0x01 0xFFFF>; + }; + + opp120-720000000 { + opp-hz = /bits/ 64 <720000000>; + opp-microvolt = <1200000 1176000 1224000>; + opp-supported-hw = <0x06 0x0080>; + }; + + oppturbo-720000000 { + opp-hz = /bits/ 64 <720000000>; + opp-microvolt = <1260000 1234800 1285200>; + opp-supported-hw = <0x01 0xFFFF>; + }; + + oppturbo-800000000 { + opp-hz = /bits/ 64 <800000000>; + opp-microvolt = <1260000 1234800 1285200>; + opp-supported-hw = <0x06 0x0100>; + }; + + oppnitro-1000000000 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <1325000 1298500 1351500>; + opp-supported-hw = <0x04 0x0200>; + }; +}; |