Cc: devicet...@vger.kernel.org
Signed-off-by: Lee Jones <lee.jo...@linaro.org>
---
.../devicetree/bindings/cpufreq/cpufreq-st.txt | 72 ++++++++++++++++++++++
1 file changed, 72 insertions(+)
create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
new file mode 100644
index 0000000..e871a9f
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
@@ -0,0 +1,72 @@
+Binding for ST's CPUFreq driver
+===============================
+
+Required properties [for working voltage scaling]:
+-------------------------------------------------
+
+Located in CPU's node:
+
+- st,syscfg : Phandle to Major number register
+ First cell: offset to major number
+- st,syscfg-eng : Phandle to Minor number and Pcode registers
+ First cell: offset to process code
+ Second cell: offset to minor number
+- st,opp-list : Bootloader provided node containing one or more
'opp@X' sub-nodes
+ - opp@{1..X} : Each 'opp@X' subnode will contain the following
properties:
+ - st,avs : List of available voltages [uV] indexed by process
code
+ - st,freq : CPU frequency [Hz] for this OPP
+ - st,cuts : Cut version this OPP is suitable for [0xFF means ALL]
+ - st,substrate : Substrate version this OPP is suitable for [0xFF
means ALL]
+
+WARNING: The st,opp-list will be provided by the bootloader. Do not attempt to
+ artificially synthesise the st,opp-list node or any of its descendants.
+ They are very platform specific and may damage the hardware if created
+ incorrectly.
+
+Required properties [if the voltage scaling properties are missing]:
+-------------------------------------------------------------------
+
+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>;
+ };
+};
+
+Example [unsafe]:
+----------------
+
+cpus {
+ cpu@0 {
+ st,syscfg = <&syscfg [major_offset]>;
+ st,syscfg-eng = <&syscfg_eng [pcode_offset] [minor_offset]>;
+
+ /* ###########################################################
*/
+ /* # WARNING: Do not attempt to copy/replicate this node !!! #
*/
+ /* ###########################################################
*/
+ st,opp-list {
+ opp0 {
+ st,avs = <1110 1150 1100 1080 1040 1020 980
930>;
+ st,freq = <1200000>;
+ st,substrate = <0xff>;
+ st,cuts = <0xff>;
+ };
+ opp1 {
+ st,avs = <1200 1200 1200 1200 1170 1140 1100
1070>;
+ st,freq = <1500000>;
+ st,substrate = <0xff>;
+ st,cuts = <0x2>;
+ };
+ };
+ };
+};
--
1.9.1
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