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 For more information about the expected DT format [See: ../opp/opp.txt].
  10
  11 Frequency Scaling only
  12 ----------------------
  13
  14 No vendor specific driver required for this.
  15
  16 Located in CPU's node:
  17
  18 - operating-points              : [See: ../power/opp.txt]
  19
  20 Example [safe]
  21 --------------
  22
  23 cpus {
  24         cpu@0 {
  25                                  /* kHz     uV   */
  26                 operating-points = <1500000 0
  27                                     1200000 0
  28                                     800000  0
  29                                     500000  0>;
  30         };
  31 };
  32
  33 Dynamic Voltage and Frequency Scaling (DVFS)
  34 --------------------------------------------
  35
  36 This requires the ST CPUFreq driver to supply 'process' and 'version' info.
  37
  38 Located in CPU's node:
  39
  40 - operating-points-v2           : [See ../power/opp.txt]
  41
  42 Example [unsafe]
  43 ----------------
  44
  45 cpus {
  46         cpu@0 {
  47                 operating-points-v2     = <&cpu0_opp_table>;
  48         };
  49 };
  50
  51 cpu0_opp_table: opp_table {
  52         compatible = "operating-points-v2";
  53
  54         /* ############################################################### */
  55         /* # WARNING: Do not attempt to copy/replicate these nodes,      # */
  56         /* #          they are only to be supplied by the bootloader !!! # */
  57         /* ############################################################### */
  58         opp0 {
  59                 /*                         Major       Minor       Substrate */
  60                 /*                         2           all         all       */
  61                 opp-supported-hw        = <0x00000004  0xffffffff  0xffffffff>;
  62                 opp-hz                  = /bits/ 64 <1500000000>;
  63                 clock-latency-ns        = <10000000>;
  64
  65                 opp-microvolt-pcode0    = <1200000>;
  66                 opp-microvolt-pcode1    = <1200000>;
  67                 opp-microvolt-pcode2    = <1200000>;
  68                 opp-microvolt-pcode3    = <1200000>;
  69                 opp-microvolt-pcode4    = <1170000>;
  70                 opp-microvolt-pcode5    = <1140000>;
  71                 opp-microvolt-pcode6    = <1100000>;
  72                 opp-microvolt-pcode7    = <1070000>;
  73         };
  74
  75         opp1 {
  76                 /*                         Major       Minor       Substrate */
  77                 /*                         all         all         all       */
  78                 opp-supported-hw        = <0xffffffff  0xffffffff  0xffffffff>;
  79                 opp-hz                  = /bits/ 64 <1200000000>;
  80                 clock-latency-ns        = <10000000>;
  81
  82                 opp-microvolt-pcode0    = <1110000>;
  83                 opp-microvolt-pcode1    = <1150000>;
  84                 opp-microvolt-pcode2    = <1100000>;
  85                 opp-microvolt-pcode3    = <1080000>;
  86                 opp-microvolt-pcode4    = <1040000>;
  87                 opp-microvolt-pcode5    = <1020000>;
  88                 opp-microvolt-pcode6    = <980000>;
  89                 opp-microvolt-pcode7    = <930000>;
  90         };
  91 };