drivers/thermal/thermal_helpers.c

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