drivers/thermal/thermal_helpers.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  thermal_helpers.c - helper functions to handle thermal devices
   4  *
   5  *  Copyright (C) 2016 Eduardo Valentin <edubezval@gmail.com>
   6  *
   7  *  Highly based on original thermal_core.c
   8  *  Copyright (C) 2008 Intel Corp
   9  *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
  10  *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/sysfs.h>
  16 #include <linux/device.h>
  17 #include <linux/err.h>
  18 #include <linux/slab.h>
  19 #include <linux/string.h>
  20
  21 #include <trace/events/thermal.h>
  22
  23 #include "thermal_core.h"
  24
  25 int get_tz_trend(struct thermal_zone_device *tz, int trip)
  26 {
  27         enum thermal_trend trend;
  28
  29         if (tz->emul_temperature || !tz->ops->get_trend ||
  30             tz->ops->get_trend(tz, trip, &trend)) {
  31                 if (tz->temperature > tz->last_temperature)
  32                         trend = THERMAL_TREND_RAISING;
  33                 else if (tz->temperature < tz->last_temperature)
  34                         trend = THERMAL_TREND_DROPPING;
  35                 else
  36                         trend = THERMAL_TREND_STABLE;
  37         }
  38
  39         return trend;
  40 }
  41 EXPORT_SYMBOL(get_tz_trend);
  42
  43 struct thermal_instance *
  44 get_thermal_instance(struct thermal_zone_device *tz,
  45                      struct thermal_cooling_device *cdev, int trip)
  46 {
  47         struct thermal_instance *pos = NULL;
  48         struct thermal_instance *target_instance = NULL;
  49
  50         mutex_lock(&tz->lock);
  51         mutex_lock(&cdev->lock);
  52
  53         list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
  54                 if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
  55                         target_instance = pos;
  56                         break;
  57                 }
  58         }
  59
  60         mutex_unlock(&cdev->lock);
  61         mutex_unlock(&tz->lock);
  62
  63         return target_instance;
  64 }
  65 EXPORT_SYMBOL(get_thermal_instance);
  66
  67 /**
  68  * thermal_zone_get_temp() - returns the temperature of a thermal zone
  69  * @tz: a valid pointer to a struct thermal_zone_device
  70  * @temp: a valid pointer to where to store the resulting temperature.
  71  *
  72  * When a valid thermal zone reference is passed, it will fetch its
  73  * temperature and fill @temp.
  74  *
  75  * Return: On success returns 0, an error code otherwise
  76  */
  77 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
  78 {
  79         int ret = -EINVAL;
  80         int count;
  81         int crit_temp = INT_MAX;
  82         enum thermal_trip_type type;
  83
  84         if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
  85                 goto exit;
  86
  87         mutex_lock(&tz->lock);
  88
  89         ret = tz->ops->get_temp(tz, temp);
  90
  91         if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
  92                 for (count = 0; count < tz->trips; count++) {
  93                         ret = tz->ops->get_trip_type(tz, count, &type);
  94                         if (!ret && type == THERMAL_TRIP_CRITICAL) {
  95                                 ret = tz->ops->get_trip_temp(tz, count,
  96                                                 &crit_temp);
  97                                 break;
  98                         }
  99                 }
 100
 101                 /*
 102                  * Only allow emulating a temperature when the real temperature
 103                  * is below the critical temperature so that the emulation code
 104                  * cannot hide critical conditions.
 105                  */
 106                 if (!ret && *temp < crit_temp)
 107                         *temp = tz->emul_temperature;
 108         }
 109
 110         mutex_unlock(&tz->lock);
 111 exit:
 112         return ret;
 113 }
 114 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
 115
 116 void thermal_zone_set_trips(struct thermal_zone_device *tz)
 117 {
 118         int low = -INT_MAX;
 119         int high = INT_MAX;
 120         int trip_temp, hysteresis;
 121         int i, ret;
 122
 123         mutex_lock(&tz->lock);
 124
 125         if (!tz->ops->set_trips || !tz->ops->get_trip_hyst)
 126                 goto exit;
 127
 128         for (i = 0; i < tz->trips; i++) {
 129                 int trip_low;
 130
 131                 tz->ops->get_trip_temp(tz, i, &trip_temp);
 132                 tz->ops->get_trip_hyst(tz, i, &hysteresis);
 133
 134                 trip_low = trip_temp - hysteresis;
 135
 136                 if (trip_low < tz->temperature && trip_low > low)
 137                         low = trip_low;
 138
 139                 if (trip_temp > tz->temperature && trip_temp < high)
 140                         high = trip_temp;
 141         }
 142
 143         /* No need to change trip points */
 144         if (tz->prev_low_trip == low && tz->prev_high_trip == high)
 145                 goto exit;
 146
 147         tz->prev_low_trip = low;
 148         tz->prev_high_trip = high;
 149
 150         dev_dbg(&tz->device,
 151                 "new temperature boundaries: %d < x < %d\n", low, high);
 152
 153         /*
 154          * Set a temperature window. When this window is left the driver
 155          * must inform the thermal core via thermal_zone_device_update.
 156          */
 157         ret = tz->ops->set_trips(tz, low, high);
 158         if (ret)
 159                 dev_err(&tz->device, "Failed to set trips: %d\n", ret);
 160
 161 exit:
 162         mutex_unlock(&tz->lock);
 163 }
 164 EXPORT_SYMBOL_GPL(thermal_zone_set_trips);
 165
 166 void thermal_cdev_update(struct thermal_cooling_device *cdev)
 167 {
 168         struct thermal_instance *instance;
 169         unsigned long target = 0;
 170
 171         mutex_lock(&cdev->lock);
 172         /* cooling device is updated*/
 173         if (cdev->updated) {
 174                 mutex_unlock(&cdev->lock);
 175                 return;
 176         }
 177
 178         /* Make sure cdev enters the deepest cooling state */
 179         list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
 180                 dev_dbg(&cdev->device, "zone%d->target=%lu\n",
 181                         instance->tz->id, instance->target);
 182                 if (instance->target == THERMAL_NO_TARGET)
 183                         continue;
 184                 if (instance->target > target)
 185                         target = instance->target;
 186         }
 187
 188         if (!cdev->ops->set_cur_state(cdev, target))
 189                 thermal_cooling_device_stats_update(cdev, target);
 190
 191         cdev->updated = true;
 192         mutex_unlock(&cdev->lock);
 193         trace_cdev_update(cdev, target);
 194         dev_dbg(&cdev->device, "set to state %lu\n", target);
 195 }
 196 EXPORT_SYMBOL(thermal_cdev_update);
 197
 198 /**
 199  * thermal_zone_get_slope - return the slope attribute of the thermal zone
 200  * @tz: thermal zone device with the slope attribute
 201  *
 202  * Return: If the thermal zone device has a slope attribute, return it, else
 203  * return 1.
 204  */
 205 int thermal_zone_get_slope(struct thermal_zone_device *tz)
 206 {
 207         if (tz && tz->tzp)
 208                 return tz->tzp->slope;
 209         return 1;
 210 }
 211 EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
 212
 213 /**
 214  * thermal_zone_get_offset - return the offset attribute of the thermal zone
 215  * @tz: thermal zone device with the offset attribute
 216  *
 217  * Return: If the thermal zone device has a offset attribute, return it, else
 218  * return 0.
 219  */
 220 int thermal_zone_get_offset(struct thermal_zone_device *tz)
 221 {
 222         if (tz && tz->tzp)
 223                 return tz->tzp->offset;
 224         return 0;
 225 }
 226 EXPORT_SYMBOL_GPL(thermal_zone_get_offset);