1 // SPDX-License-Identifier: GPL-2.0
3 * thermal_helpers.c - helper functions to handle thermal devices
5 * Copyright (C) 2016 Eduardo Valentin <edubezval@gmail.com>
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>
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
22 #include <trace/events/thermal.h>
24 #include "thermal_core.h"
26 int get_tz_trend(struct thermal_zone_device *tz, int trip)
28 enum thermal_trend trend;
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;
37 trend = THERMAL_TREND_STABLE;
43 struct thermal_instance *
44 get_thermal_instance(struct thermal_zone_device *tz,
45 struct thermal_cooling_device *cdev, int trip)
47 struct thermal_instance *pos = NULL;
48 struct thermal_instance *target_instance = NULL;
50 mutex_lock(&tz->lock);
51 mutex_lock(&cdev->lock);
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;
60 mutex_unlock(&cdev->lock);
61 mutex_unlock(&tz->lock);
63 return target_instance;
65 EXPORT_SYMBOL(get_thermal_instance);
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.
72 * When a valid thermal zone reference is passed, it will fetch its
73 * temperature and fill @temp.
75 * Both tz and tz->ops must be valid pointers when calling this function,
76 * and the tz->ops->get_temp callback must be provided.
77 * The function must be called under tz->lock.
79 * Return: On success returns 0, an error code otherwise
81 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
85 int crit_temp = INT_MAX;
86 enum thermal_trip_type type;
88 lockdep_assert_held(&tz->lock);
90 ret = tz->ops->get_temp(tz, temp);
92 if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
93 for (count = 0; count < tz->num_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,
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.
107 if (!ret && *temp < crit_temp)
108 *temp = tz->emul_temperature;
115 * thermal_zone_get_temp() - returns the temperature of a thermal zone
116 * @tz: a valid pointer to a struct thermal_zone_device
117 * @temp: a valid pointer to where to store the resulting temperature.
119 * When a valid thermal zone reference is passed, it will fetch its
120 * temperature and fill @temp.
122 * Return: On success returns 0, an error code otherwise
124 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
128 if (IS_ERR_OR_NULL(tz))
131 mutex_lock(&tz->lock);
133 if (!tz->ops->get_temp) {
138 if (device_is_registered(&tz->device))
139 ret = __thermal_zone_get_temp(tz, temp);
144 mutex_unlock(&tz->lock);
148 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
151 * __thermal_zone_set_trips - Computes the next trip points for the driver
152 * @tz: a pointer to a thermal zone device structure
154 * The function computes the next temperature boundaries by browsing
155 * the trip points. The result is the closer low and high trip points
156 * to the current temperature. These values are passed to the backend
157 * driver to let it set its own notification mechanism (usually an
160 * This function must be called with tz->lock held. Both tz and tz->ops
161 * must be valid pointers.
163 * It does not return a value
165 void __thermal_zone_set_trips(struct thermal_zone_device *tz)
169 int trip_temp, hysteresis;
172 lockdep_assert_held(&tz->lock);
174 if (!tz->ops->set_trips || !tz->ops->get_trip_hyst)
177 for (i = 0; i < tz->num_trips; i++) {
180 tz->ops->get_trip_temp(tz, i, &trip_temp);
181 tz->ops->get_trip_hyst(tz, i, &hysteresis);
183 trip_low = trip_temp - hysteresis;
185 if (trip_low < tz->temperature && trip_low > low)
188 if (trip_temp > tz->temperature && trip_temp < high)
192 /* No need to change trip points */
193 if (tz->prev_low_trip == low && tz->prev_high_trip == high)
196 tz->prev_low_trip = low;
197 tz->prev_high_trip = high;
200 "new temperature boundaries: %d < x < %d\n", low, high);
203 * Set a temperature window. When this window is left the driver
204 * must inform the thermal core via thermal_zone_device_update.
206 ret = tz->ops->set_trips(tz, low, high);
208 dev_err(&tz->device, "Failed to set trips: %d\n", ret);
211 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev,
214 if (cdev->ops->set_cur_state(cdev, target))
217 thermal_notify_cdev_state_update(cdev->id, target);
218 thermal_cooling_device_stats_update(cdev, target);
221 void __thermal_cdev_update(struct thermal_cooling_device *cdev)
223 struct thermal_instance *instance;
224 unsigned long target = 0;
226 /* Make sure cdev enters the deepest cooling state */
227 list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
228 dev_dbg(&cdev->device, "zone%d->target=%lu\n",
229 instance->tz->id, instance->target);
230 if (instance->target == THERMAL_NO_TARGET)
232 if (instance->target > target)
233 target = instance->target;
236 thermal_cdev_set_cur_state(cdev, target);
238 trace_cdev_update(cdev, target);
239 dev_dbg(&cdev->device, "set to state %lu\n", target);
243 * thermal_cdev_update - update cooling device state if needed
244 * @cdev: pointer to struct thermal_cooling_device
246 * Update the cooling device state if there is a need.
248 void thermal_cdev_update(struct thermal_cooling_device *cdev)
250 mutex_lock(&cdev->lock);
251 if (!cdev->updated) {
252 __thermal_cdev_update(cdev);
253 cdev->updated = true;
255 mutex_unlock(&cdev->lock);
259 * thermal_zone_get_slope - return the slope attribute of the thermal zone
260 * @tz: thermal zone device with the slope attribute
262 * Return: If the thermal zone device has a slope attribute, return it, else
265 int thermal_zone_get_slope(struct thermal_zone_device *tz)
268 return tz->tzp->slope;
271 EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
274 * thermal_zone_get_offset - return the offset attribute of the thermal zone
275 * @tz: thermal zone device with the offset attribute
277 * Return: If the thermal zone device has a offset attribute, return it, else
280 int thermal_zone_get_offset(struct thermal_zone_device *tz)
283 return tz->tzp->offset;
286 EXPORT_SYMBOL_GPL(thermal_zone_get_offset);