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authorLeonard Crestez <leonard.crestez@nxp.com>2019-05-13 14:01:39 +0300
committerViresh Kumar <viresh.kumar@linaro.org>2019-05-20 10:18:12 +0300
commita02177a39344b643dccfa3b18fa5c1fc4984e1e5 (patch)
treec853224d5b03a0490963e1963d112ed2ddec25ec /Documentation/devicetree/bindings/cpufreq
parent4d28ba1d62c48d5242ca30fa0051ab3498bc5c5b (diff)
downloadlinux-a02177a39344b643dccfa3b18fa5c1fc4984e1e5.tar.xz
dt-bindings: imx-cpufreq-dt: Document opp-supported-hw usage
The interpretation of opp-supported-hw bits for imx-cpufreq-dt driver is not very obvious so attempt to explain it. There is no OF compat string associated. Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'Documentation/devicetree/bindings/cpufreq')
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+i.MX CPUFreq-DT OPP bindings
+================================
+
+Certain i.MX SoCs support different OPPs depending on the "market segment" and
+"speed grading" value which are written in fuses. These bits are combined with
+the opp-supported-hw values for each OPP to check if the OPP is allowed.
+
+Required properties:
+--------------------
+
+For each opp entry in 'operating-points-v2' table:
+- opp-supported-hw: Two bitmaps indicating:
+ - Supported speed grade mask
+ - Supported market segment mask
+ 0: Consumer
+ 1: Extended Consumer
+ 2: Industrial
+ 3: Automotive
+
+Example:
+--------
+
+opp_table {
+ compatible = "operating-points-v2";
+ opp-1000000000 {
+ opp-hz = /bits/ 64 <1000000000>;
+ /* grade >= 0, consumer only */
+ opp-supported-hw = <0xf>, <0x3>;
+ };
+
+ opp-1300000000 {
+ opp-hz = /bits/ 64 <1300000000>;
+ opp-microvolt = <1000000>;
+ /* grade >= 1, all segments */
+ opp-supported-hw = <0xe>, <0x7>;
+ };
+}