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>

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
new file mode 100644 (file)
index 0000000..d91a02a
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
@@ -0,0 +1,91 @@
+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>;
+       };
+};