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/device.h> 16 #include <linux/err.h> 17 #include <linux/export.h> 18 #include <linux/slab.h> 19 #include <linux/string.h> 20 #include <linux/sysfs.h> 21 22 #include <trace/events/thermal.h> 23 24 #include "thermal_core.h" 25 26 int get_tz_trend(struct thermal_zone_device *tz, int trip) 27 { 28 enum thermal_trend trend; 29 30 if (tz->emul_temperature || !tz->ops->get_trend || 31 tz->ops->get_trend(tz, trip, &trend)) { 32 if (tz->temperature > tz->last_temperature) 33 trend = THERMAL_TREND_RAISING; 34 else if (tz->temperature < tz->last_temperature) 35 trend = THERMAL_TREND_DROPPING; 36 else 37 trend = THERMAL_TREND_STABLE; 38 } 39 40 return trend; 41 } 42 EXPORT_SYMBOL(get_tz_trend); 43 44 struct thermal_instance * 45 get_thermal_instance(struct thermal_zone_device *tz, 46 struct thermal_cooling_device *cdev, int trip) 47 { 48 struct thermal_instance *pos = NULL; 49 struct thermal_instance *target_instance = NULL; 50 51 mutex_lock(&tz->lock); 52 mutex_lock(&cdev->lock); 53 54 list_for_each_entry(pos, &tz->thermal_instances, tz_node) { 55 if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) { 56 target_instance = pos; 57 break; 58 } 59 } 60 61 mutex_unlock(&cdev->lock); 62 mutex_unlock(&tz->lock); 63 64 return target_instance; 65 } 66 EXPORT_SYMBOL(get_thermal_instance); 67 68 /** 69 * thermal_zone_get_temp() - returns the temperature of a thermal zone 70 * @tz: a valid pointer to a struct thermal_zone_device 71 * @temp: a valid pointer to where to store the resulting temperature. 72 * 73 * When a valid thermal zone reference is passed, it will fetch its 74 * temperature and fill @temp. 75 * 76 * Return: On success returns 0, an error code otherwise 77 */ 78 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp) 79 { 80 int ret = -EINVAL; 81 int count; 82 int crit_temp = INT_MAX; 83 enum thermal_trip_type type; 84 85 if (!tz || IS_ERR(tz) || !tz->ops->get_temp) 86 goto exit; 87 88 mutex_lock(&tz->lock); 89 90 ret = tz->ops->get_temp(tz, temp); 91 92 if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) { 93 for (count = 0; count < tz->trips; count++) { 94 ret = tz->ops->get_trip_type(tz, count, &type); 95 if (!ret && type == THERMAL_TRIP_CRITICAL) { 96 ret = tz->ops->get_trip_temp(tz, count, 97 &crit_temp); 98 break; 99 } 100 } 101 102 /* 103 * Only allow emulating a temperature when the real temperature 104 * is below the critical temperature so that the emulation code 105 * cannot hide critical conditions. 106 */ 107 if (!ret && *temp < crit_temp) 108 *temp = tz->emul_temperature; 109 } 110 111 mutex_unlock(&tz->lock); 112 exit: 113 return ret; 114 } 115 EXPORT_SYMBOL_GPL(thermal_zone_get_temp); 116 117 /** 118 * thermal_zone_set_trips - Computes the next trip points for the driver 119 * @tz: a pointer to a thermal zone device structure 120 * 121 * The function computes the next temperature boundaries by browsing 122 * the trip points. The result is the closer low and high trip points 123 * to the current temperature. These values are passed to the backend 124 * driver to let it set its own notification mechanism (usually an 125 * interrupt). 126 * 127 * It does not return a value 128 */ 129 void thermal_zone_set_trips(struct thermal_zone_device *tz) 130 { 131 int low = -INT_MAX; 132 int high = INT_MAX; 133 int trip_temp, hysteresis; 134 int i, ret; 135 136 mutex_lock(&tz->lock); 137 138 if (!tz->ops->set_trips || !tz->ops->get_trip_hyst) 139 goto exit; 140 141 for (i = 0; i < tz->trips; i++) { 142 int trip_low; 143 144 tz->ops->get_trip_temp(tz, i, &trip_temp); 145 tz->ops->get_trip_hyst(tz, i, &hysteresis); 146 147 trip_low = trip_temp - hysteresis; 148 149 if (trip_low < tz->temperature && trip_low > low) 150 low = trip_low; 151 152 if (trip_temp > tz->temperature && trip_temp < high) 153 high = trip_temp; 154 } 155 156 /* No need to change trip points */ 157 if (tz->prev_low_trip == low && tz->prev_high_trip == high) 158 goto exit; 159 160 tz->prev_low_trip = low; 161 tz->prev_high_trip = high; 162 163 dev_dbg(&tz->device, 164 "new temperature boundaries: %d < x < %d\n", low, high); 165 166 /* 167 * Set a temperature window. When this window is left the driver 168 * must inform the thermal core via thermal_zone_device_update. 169 */ 170 ret = tz->ops->set_trips(tz, low, high); 171 if (ret) 172 dev_err(&tz->device, "Failed to set trips: %d\n", ret); 173 174 exit: 175 mutex_unlock(&tz->lock); 176 } 177 178 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev, 179 int target) 180 { 181 if (cdev->ops->set_cur_state(cdev, target)) 182 return; 183 184 thermal_notify_cdev_state_update(cdev->id, target); 185 thermal_cooling_device_stats_update(cdev, target); 186 } 187 188 void thermal_cdev_update(struct thermal_cooling_device *cdev) 189 { 190 struct thermal_instance *instance; 191 unsigned long target = 0; 192 193 mutex_lock(&cdev->lock); 194 /* cooling device is updated*/ 195 if (cdev->updated) { 196 mutex_unlock(&cdev->lock); 197 return; 198 } 199 200 /* Make sure cdev enters the deepest cooling state */ 201 list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) { 202 dev_dbg(&cdev->device, "zone%d->target=%lu\n", 203 instance->tz->id, instance->target); 204 if (instance->target == THERMAL_NO_TARGET) 205 continue; 206 if (instance->target > target) 207 target = instance->target; 208 } 209 210 thermal_cdev_set_cur_state(cdev, target); 211 212 cdev->updated = true; 213 mutex_unlock(&cdev->lock); 214 trace_cdev_update(cdev, target); 215 dev_dbg(&cdev->device, "set to state %lu\n", target); 216 } 217 EXPORT_SYMBOL(thermal_cdev_update); 218 219 /** 220 * thermal_zone_get_slope - return the slope attribute of the thermal zone 221 * @tz: thermal zone device with the slope attribute 222 * 223 * Return: If the thermal zone device has a slope attribute, return it, else 224 * return 1. 225 */ 226 int thermal_zone_get_slope(struct thermal_zone_device *tz) 227 { 228 if (tz && tz->tzp) 229 return tz->tzp->slope; 230 return 1; 231 } 232 EXPORT_SYMBOL_GPL(thermal_zone_get_slope); 233 234 /** 235 * thermal_zone_get_offset - return the offset attribute of the thermal zone 236 * @tz: thermal zone device with the offset attribute 237 * 238 * Return: If the thermal zone device has a offset attribute, return it, else 239 * return 0. 240 */ 241 int thermal_zone_get_offset(struct thermal_zone_device *tz) 242 { 243 if (tz && tz->tzp) 244 return tz->tzp->offset; 245 return 0; 246 } 247 EXPORT_SYMBOL_GPL(thermal_zone_get_offset); 248