thermal: sysfs: Add a new sysfs node emul_temp for thermal emulation

This patch adds support to set the emulated temperature method in
thermal zone (sensor). After setting this feature thermal zone may
report this temperature and not the actual temperature. The emulation
implementation may be based on sensor capability through platform
specific handler or pure software emulation if no platform handler defined.

This is useful in debugging different temperature threshold and its
associated cooling action. Critical threshold's cannot be emulated.
Writing 0 on this node should disable emulation.

Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

1 files changed, 68 insertions, 11 deletions

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 0a1bf6b..0675687 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -378,24 +378,54 @@ static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
 	monitor_thermal_zone(tz);
 }
 
+static int thermal_zone_get_temp(struct thermal_zone_device *tz,
+				unsigned long *temp)
+{
+	int ret = 0, count;
+	unsigned long crit_temp = -1UL;
+	enum thermal_trip_type type;
+
+	mutex_lock(&tz->lock);
+
+	ret = tz->ops->get_temp(tz, temp);
+#ifdef CONFIG_THERMAL_EMULATION
+	if (!tz->emul_temperature)
+		goto skip_emul;
+
+	for (count = 0; count < tz->trips; count++) {
+		ret = tz->ops->get_trip_type(tz, count, &type);
+		if (!ret && type == THERMAL_TRIP_CRITICAL) {
+			ret = tz->ops->get_trip_temp(tz, count, &crit_temp);
+			break;
+		}
+	}
+
+	if (ret)
+		goto skip_emul;
+
+	if (*temp < crit_temp)
+		*temp = tz->emul_temperature;
+skip_emul:
+#endif
+	mutex_unlock(&tz->lock);
+	return ret;
+}
+
 static void update_temperature(struct thermal_zone_device *tz)
 {
 	long temp;
 	int ret;
 
-	mutex_lock(&tz->lock);
-
-	ret = tz->ops->get_temp(tz, &temp);
+	ret = thermal_zone_get_temp(tz, &temp);
 	if (ret) {
 		dev_warn(&tz->device, "failed to read out thermal zone %d\n",
 			 tz->id);
-		goto exit;
+		return;
 	}
 
+	mutex_lock(&tz->lock);
 	tz->last_temperature = tz->temperature;
 	tz->temperature = temp;
-
-exit:
 	mutex_unlock(&tz->lock);
 }
 
@@ -438,10 +468,7 @@ temp_show(struct device *dev, struct device_attribute *attr, char *buf)
 	long temperature;
 	int ret;
 
-	if (!tz->ops->get_temp)
-		return -EPERM;
-
-	ret = tz->ops->get_temp(tz, &temperature);
+	ret = thermal_zone_get_temp(tz, &temperature);
 
 	if (ret)
 		return ret;
@@ -701,6 +728,31 @@ policy_show(struct device *dev, struct device_attribute *devattr, char *buf)
 	return sprintf(buf, "%s\n", tz->governor->name);
 }
 
+#ifdef CONFIG_THERMAL_EMULATION
+static ssize_t
+emul_temp_store(struct device *dev, struct device_attribute *attr,
+		     const char *buf, size_t count)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	int ret = 0;
+	unsigned long temperature;
+
+	if (kstrtoul(buf, 10, &temperature))
+		return -EINVAL;
+
+	if (!tz->ops->set_emul_temp) {
+		mutex_lock(&tz->lock);
+		tz->emul_temperature = temperature;
+		mutex_unlock(&tz->lock);
+	} else {
+		ret = tz->ops->set_emul_temp(tz, temperature);
+	}
+
+	return ret ? ret : count;
+}
+static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
+#endif/*CONFIG_THERMAL_EMULATION*/
+
 static DEVICE_ATTR(type, 0444, type_show, NULL);
 static DEVICE_ATTR(temp, 0444, temp_show, NULL);
 static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
@@ -843,7 +895,7 @@ temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
 				       temp_input);
 	struct thermal_zone_device *tz = temp->tz;
 
-	ret = tz->ops->get_temp(tz, &temperature);
+	ret = thermal_zone_get_temp(tz, &temperature);
 
 	if (ret)
 		return ret;
@@ -1596,6 +1648,11 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
 			goto unregister;
 	}
 
+#ifdef CONFIG_THERMAL_EMULATION
+	result = device_create_file(&tz->device, &dev_attr_emul_temp);
+	if (result)
+		goto unregister;
+#endif
 	/* Create policy attribute */
 	result = device_create_file(&tz->device, &dev_attr_policy);
 	if (result)