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dt: cpufreq: st: Provide bindings for ST's CPUFreq implementation 

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lee Jones 2015-12-10 09:42:17 +00:00 committed by Rafael J. Wysocki
parent ab0ea257fc
commit b122bcd947
1 changed files with 91 additions and 0 deletions
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Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt Normal file
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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.
For more information about the expected DT format [See: ../opp/opp.txt].
Frequency Scaling only
----------------------
No vendor specific driver required for this.
Located in CPU's node:
- operating-points : [See: ../power/opp.txt]
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.txt]
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>;
};
};