Documentation/devicetree/bindings/thermal/nvidia,tegra124-soctherm.txt

   1 Tegra124 SOCTHERM thermal management system
   2
   3 The SOCTHERM IP block contains thermal sensors, support for polled
   4 or interrupt-based thermal monitoring, CPU and GPU throttling based
   5 on temperature trip points, and handling external overcurrent
   6 notifications. It is also used to manage emergency shutdown in an
   7 overheating situation.
   8
   9 Required properties :
  10 - compatible : For Tegra124, must contain "nvidia,tegra124-soctherm".
  11   For Tegra132, must contain "nvidia,tegra132-soctherm".
  12   For Tegra210, must contain "nvidia,tegra210-soctherm".
  13 - reg : Should contain at least 2 entries for each entry in reg-names:
  14   - SOCTHERM register set
  15   - Tegra CAR register set: Required for Tegra124 and Tegra210.
  16   - CCROC register set: Required for Tegra132.
  17 - reg-names :  Should contain at least 2 entries:
  18   - soctherm-reg
  19   - car-reg
  20   - ccroc-reg
  21 - interrupts : Defines the interrupt used by SOCTHERM
  22 - clocks : Must contain an entry for each entry in clock-names.
  23   See ../clocks/clock-bindings.txt for details.
  24 - clock-names : Must include the following entries:
  25   - tsensor
  26   - soctherm
  27 - resets : Must contain an entry for each entry in reset-names.
  28   See ../reset/reset.txt for details.
  29 - reset-names : Must include the following entries:
  30   - soctherm
  31 - #thermal-sensor-cells : Should be 1. See ./thermal.txt for a description
  32     of this property. See <dt-bindings/thermal/tegra124-soctherm.h> for a
  33     list of valid values when referring to thermal sensors.
  34 - throttle-cfgs: A sub-node which is a container of configuration for each
  35     hardware throttle events. These events can be set as cooling devices.
  36   * throttle events: Sub-nodes must be named as "light" or "heavy".
  37       Properties:
  38       - nvidia,priority: Each throttles has its own throttle settings, so the
  39         SW need to set priorities for various throttle, the HW arbiter can select
  40         the final throttle settings.
  41         Bigger value indicates higher priority, In general, higher priority
  42         translates to lower target frequency. SW needs to ensure that critical
  43         thermal alarms are given higher priority, and ensure that there is
  44         no race if priority of two vectors is set to the same value.
  45         The range of this value is 1~100.
  46       - nvidia,cpu-throt-percent: This property is for Tegra124 and Tegra210.
  47         It is the throttling depth of pulse skippers, it's the percentage
  48         throttling.
  49       - nvidia,cpu-throt-level: This property is only for Tegra132, it is the
  50         level of pulse skippers, which used to throttle clock frequencies. It
  51         indicates cpu clock throttling depth, and the depth can be programmed.
  52         Must set as following values:
  53         TEGRA_SOCTHERM_THROT_LEVEL_LOW, TEGRA_SOCTHERM_THROT_LEVEL_MED
  54         TEGRA_SOCTHERM_THROT_LEVEL_HIGH, TEGRA_SOCTHERM_THROT_LEVEL_NONE
  55       - #cooling-cells: Should be 1. This cooling device only support on/off state.
  56         See ./thermal.txt for a description of this property.
  57
  58 Note:
  59 - the "critical" type trip points will be set to SOC_THERM hardware as the
  60 shut down temperature. Once the temperature of this thermal zone is higher
  61 than it, the system will be shutdown or reset by hardware.
  62 - the "hot" type trip points will be set to SOC_THERM hardware as the throttle
  63 temperature. Once the the temperature of this thermal zone is higher
  64 than it, it will trigger the HW throttle event.
  65
  66 Example :
  67
  68         soctherm@700e2000 {
  69                 compatible = "nvidia,tegra124-soctherm";
  70                 reg = <0x0 0x700e2000 0x0 0x600  /* SOC_THERM reg_base */
  71                         0x0 0x60006000 0x0 0x400 /* CAR reg_base */
  72                 reg-names = "soctherm-reg", "car-reg";
  73                 interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>;
  74                 clocks = <&tegra_car TEGRA124_CLK_TSENSOR>,
  75                         <&tegra_car TEGRA124_CLK_SOC_THERM>;
  76                 clock-names = "tsensor", "soctherm";
  77                 resets = <&tegra_car 78>;
  78                 reset-names = "soctherm";
  79
  80                 #thermal-sensor-cells = <1>;
  81
  82                 throttle-cfgs {
  83                         /*
  84                          * When the "heavy" cooling device triggered,
  85                          * the HW will skip cpu clock's pulse in 85% depth
  86                          */
  87                         throttle_heavy: heavy {
  88                                 nvidia,priority = <100>;
  89                                 nvidia,cpu-throt-percent = <85>;
  90
  91                                 #cooling-cells = <1>;
  92                         };
  93
  94                         /*
  95                          * When the "light" cooling device triggered,
  96                          * the HW will skip cpu clock's pulse in 50% depth
  97                          */
  98                         throttle_light: light {
  99                                 nvidia,priority = <80>;
 100                                 nvidia,cpu-throt-percent = <50>;
 101
 102                                 #cooling-cells = <1>;
 103                         };
 104
 105                         /*
 106                          * If these two devices are triggered in same time, the HW throttle
 107                          * arbiter will select the highest priority as the final throttle
 108                          * settings to skip cpu pulse.
 109                          */
 110                 };
 111         };
 112
 113 Example: referring to Tegra132's "reg", "reg-names" and "throttle-cfgs" :
 114
 115         soctherm@700e2000 {
 116                 compatible = "nvidia,tegra132-soctherm";
 117                 reg = <0x0 0x700e2000 0x0 0x600  /* SOC_THERM reg_base */
 118                         0x0 0x70040000 0x0 0x200>; /* CCROC reg_base */;
 119                 reg-names = "soctherm-reg", "ccroc-reg";
 120
 121                 throttle-cfgs {
 122                         /*
 123                          * When the "heavy" cooling device triggered,
 124                          * the HW will skip cpu clock's pulse in HIGH level
 125                          */
 126                         throttle_heavy: heavy {
 127                                 nvidia,priority = <100>;
 128                                 nvidia,cpu-throt-level = <TEGRA_SOCTHERM_THROT_LEVEL_HIGH>;
 129
 130                                 #cooling-cells = <1>;
 131                         };
 132
 133                         /*
 134                          * When the "light" cooling device triggered,
 135                          * the HW will skip cpu clock's pulse in MED level
 136                          */
 137                         throttle_light: light {
 138                                 nvidia,priority = <80>;
 139                                 nvidia,cpu-throt-level = <TEGRA_SOCTHERM_THROT_LEVEL_MED>;
 140
 141                                 #cooling-cells = <1>;
 142                         };
 143
 144                         /*
 145                          * If these two devices are triggered in same time, the HW throttle
 146                          * arbiter will select the highest priority as the final throttle
 147                          * settings to skip cpu pulse.
 148                          */
 149
 150                 };
 151         };
 152
 153 Example: referring to thermal sensors :
 154
 155        thermal-zones {
 156                 cpu {
 157                         polling-delay-passive = <1000>;
 158                         polling-delay = <1000>;
 159
 160                         thermal-sensors =
 161                                 <&soctherm TEGRA124_SOCTHERM_SENSOR_CPU>;
 162
 163                         trips {
 164                                 cpu_shutdown_trip: shutdown-trip {
 165                                         temperature = <102500>;
 166                                         hysteresis = <1000>;
 167                                         type = "critical";
 168                                 };
 169
 170                                 cpu_throttle_trip: throttle-trip {
 171                                         temperature = <100000>;
 172                                         hysteresis = <1000>;
 173                                         type = "hot";
 174                                 };
 175                         };
 176
 177                         cooling-maps {
 178                                 map0 {
 179                                         trip = <&cpu_throttle_trip>;
 180                                         cooling-device = <&throttle_heavy 1 1>;
 181                                 };
 182                         };
 183                 };
 184         };