229 lines
6.7 KiB
C
229 lines
6.7 KiB
C
/*
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* step_wise.c - A step-by-step Thermal throttling governor
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*
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* Copyright (C) 2012 Intel Corp
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* Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*/
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#include <linux/thermal.h>
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#include <trace/events/thermal.h>
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#include "thermal_core.h"
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/*
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* If the temperature is higher than a trip point,
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* a. if the trend is THERMAL_TREND_RAISING, use higher cooling
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* state for this trip point
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* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
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* state for this trip point
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* c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit
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* for this trip point
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* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
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* for this trip point
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* If the temperature is lower than a trip point,
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* a. if the trend is THERMAL_TREND_RAISING, do nothing
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* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
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* state for this trip point, if the cooling state already
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* equals lower limit, deactivate the thermal instance
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* c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing
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* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit,
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* if the cooling state already equals lower limit,
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* deactivate the thermal instance
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*/
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static unsigned long get_target_state(struct thermal_instance *instance,
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enum thermal_trend trend, bool throttle)
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{
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struct thermal_cooling_device *cdev = instance->cdev;
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unsigned long cur_state;
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unsigned long next_target;
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/*
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* We keep this instance the way it is by default.
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* Otherwise, we use the current state of the
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* cdev in use to determine the next_target.
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*/
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cdev->ops->get_cur_state(cdev, &cur_state);
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next_target = instance->target;
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dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
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if (!instance->initialized) {
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if (throttle) {
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next_target = (cur_state + 1) >= instance->upper ?
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instance->upper :
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((cur_state + 1) < instance->lower ?
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instance->lower : (cur_state + 1));
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} else {
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next_target = THERMAL_NO_TARGET;
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}
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return next_target;
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}
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switch (trend) {
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case THERMAL_TREND_RAISING:
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if (throttle) {
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next_target = cur_state < instance->upper ?
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(cur_state + 1) : instance->upper;
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if (next_target < instance->lower)
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next_target = instance->lower;
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}
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break;
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case THERMAL_TREND_RAISE_FULL:
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if (throttle)
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next_target = instance->upper;
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break;
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case THERMAL_TREND_DROPPING:
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if (cur_state <= instance->lower) {
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if (!throttle)
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next_target = THERMAL_NO_TARGET;
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} else {
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next_target = cur_state - 1;
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if (next_target > instance->upper)
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next_target = instance->upper;
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}
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break;
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case THERMAL_TREND_DROP_FULL:
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if (cur_state == instance->lower) {
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if (!throttle)
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next_target = THERMAL_NO_TARGET;
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} else
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next_target = instance->lower;
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break;
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default:
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break;
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}
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return next_target;
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}
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static void update_passive_instance(struct thermal_zone_device *tz,
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enum thermal_trip_type type, int value)
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{
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/*
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* If value is +1, activate a passive instance.
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* If value is -1, deactivate a passive instance.
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*/
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if (type == THERMAL_TRIP_PASSIVE || type == THERMAL_TRIPS_NONE)
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tz->passive += value;
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}
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static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
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{
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int trip_temp;
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enum thermal_trip_type trip_type;
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enum thermal_trend trend;
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struct thermal_instance *instance;
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bool throttle = false;
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int old_target;
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if (trip == THERMAL_TRIPS_NONE) {
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trip_temp = tz->forced_passive;
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trip_type = THERMAL_TRIPS_NONE;
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} else {
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tz->ops->get_trip_temp(tz, trip, &trip_temp);
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tz->ops->get_trip_type(tz, trip, &trip_type);
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}
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trend = get_tz_trend(tz, trip);
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if (tz->temperature >= trip_temp) {
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throttle = true;
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trace_thermal_zone_trip(tz, trip, trip_type);
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}
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dev_dbg(&tz->device, "Trip%d[type=%d,temp=%d]:trend=%d,throttle=%d\n",
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trip, trip_type, trip_temp, trend, throttle);
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mutex_lock(&tz->lock);
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list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
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if (instance->trip != trip)
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continue;
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old_target = instance->target;
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instance->target = get_target_state(instance, trend, throttle);
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dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
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old_target, (int)instance->target);
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if (instance->initialized && old_target == instance->target)
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continue;
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/* Activate a passive thermal instance */
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if (old_target == THERMAL_NO_TARGET &&
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instance->target != THERMAL_NO_TARGET)
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update_passive_instance(tz, trip_type, 1);
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/* Deactivate a passive thermal instance */
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else if (old_target != THERMAL_NO_TARGET &&
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instance->target == THERMAL_NO_TARGET)
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update_passive_instance(tz, trip_type, -1);
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instance->initialized = true;
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instance->cdev->updated = false; /* cdev needs update */
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}
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mutex_unlock(&tz->lock);
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}
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/**
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* step_wise_throttle - throttles devices associated with the given zone
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* @tz - thermal_zone_device
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* @trip - the trip point
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* @trip_type - type of the trip point
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*
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* Throttling Logic: This uses the trend of the thermal zone to throttle.
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* If the thermal zone is 'heating up' this throttles all the cooling
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* devices associated with the zone and its particular trip point, by one
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* step. If the zone is 'cooling down' it brings back the performance of
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* the devices by one step.
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*/
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static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
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{
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struct thermal_instance *instance;
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thermal_zone_trip_update(tz, trip);
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if (tz->forced_passive)
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thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE);
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mutex_lock(&tz->lock);
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list_for_each_entry(instance, &tz->thermal_instances, tz_node)
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thermal_cdev_update(instance->cdev);
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mutex_unlock(&tz->lock);
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return 0;
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}
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static struct thermal_governor thermal_gov_step_wise = {
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.name = "step_wise",
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.throttle = step_wise_throttle,
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};
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int thermal_gov_step_wise_register(void)
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{
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return thermal_register_governor(&thermal_gov_step_wise);
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}
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void thermal_gov_step_wise_unregister(void)
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{
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thermal_unregister_governor(&thermal_gov_step_wise);
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}
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