Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt

   1 Binding for ST's CPUFreq driver
   2 ===============================
   3
   4 ST's CPUFreq driver attempts to read 'process' and 'version' attributes
   5 from the SoC, then supplies the OPP framework with 'prop' and 'supported
   6 hardware' information respectively.  The framework is then able to read
   7 the DT and operate in the usual way.
   8
   9 Frequency Scaling only
  10 ----------------------
  11
  12 No vendor specific driver required for this.
  13
  14 Located in CPU's node:
  15
  16 - operating-points              : [See: ../power/opp-v1.yaml]
  17
  18 Example [safe]
  19 --------------
  20
  21 cpus {
  22         cpu@0 {
  23                                  /* kHz     uV   */
  24                 operating-points = <1500000 0
  25                                     1200000 0
  26                                     800000  0
  27                                     500000  0>;
  28         };
  29 };
  30
  31 Dynamic Voltage and Frequency Scaling (DVFS)
  32 --------------------------------------------
  33
  34 This requires the ST CPUFreq driver to supply 'process' and 'version' info.
  35
  36 Located in CPU's node:
  37
  38 - operating-points-v2           : [See ../power/opp-v2.yaml]
  39
  40 Example [unsafe]
  41 ----------------
  42
  43 cpus {
  44         cpu@0 {
  45                 operating-points-v2     = <&cpu0_opp_table>;
  46         };
  47 };
  48
  49 cpu0_opp_table: opp_table {
  50         compatible = "operating-points-v2";
  51
  52         /* ############################################################### */
  53         /* # WARNING: Do not attempt to copy/replicate these nodes,      # */
  54         /* #          they are only to be supplied by the bootloader !!! # */
  55         /* ############################################################### */
  56         opp0 {
  57                 /*                         Major       Minor       Substrate */
  58                 /*                         2           all         all       */
  59                 opp-supported-hw        = <0x00000004  0xffffffff  0xffffffff>;
  60                 opp-hz                  = /bits/ 64 <1500000000>;
  61                 clock-latency-ns        = <10000000>;
  62
  63                 opp-microvolt-pcode0    = <1200000>;
  64                 opp-microvolt-pcode1    = <1200000>;
  65                 opp-microvolt-pcode2    = <1200000>;
  66                 opp-microvolt-pcode3    = <1200000>;
  67                 opp-microvolt-pcode4    = <1170000>;
  68                 opp-microvolt-pcode5    = <1140000>;
  69                 opp-microvolt-pcode6    = <1100000>;
  70                 opp-microvolt-pcode7    = <1070000>;
  71         };
  72
  73         opp1 {
  74                 /*                         Major       Minor       Substrate */
  75                 /*                         all         all         all       */
  76                 opp-supported-hw        = <0xffffffff  0xffffffff  0xffffffff>;
  77                 opp-hz                  = /bits/ 64 <1200000000>;
  78                 clock-latency-ns        = <10000000>;
  79
  80                 opp-microvolt-pcode0    = <1110000>;
  81                 opp-microvolt-pcode1    = <1150000>;
  82                 opp-microvolt-pcode2    = <1100000>;
  83                 opp-microvolt-pcode3    = <1080000>;
  84                 opp-microvolt-pcode4    = <1040000>;
  85                 opp-microvolt-pcode5    = <1020000>;
  86                 opp-microvolt-pcode6    = <980000>;
  87                 opp-microvolt-pcode7    = <930000>;
  88         };
  89 };