mt76: mt7915: add thermal cooling device support

Thermal cooling device support is added to control the temperature by
throttling the data transmission for the given duration. Throttling is
done by adjusting Tx period by given percentage of time. The thermal
device allows user to configure duty cycle.

Throttling can be disabled by setting the duty cycle to 0. The cooling
device can be found under /sys/class/thermal/cooling_deviceX/.
Corresponding soft link to this device can be found under phy folder

To set duty cycle as 80%,
echo 80 > /sys/class/ieee80211/phy*/cooling_device/cur_state

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

1 files changed, 73 insertions, 0 deletions

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/init.c b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
index ff7c38b87ed1..39f3639aa096 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
@@ -4,6 +4,7 @@
 #include <linux/etherdevice.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
+#include <linux/thermal.h>
 #include "mt7915.h"
 #include "mac.h"
 #include "mcu.h"
@@ -65,11 +66,81 @@ static struct attribute *mt7915_hwmon_attrs[] = {
 };
 ATTRIBUTE_GROUPS(mt7915_hwmon);
 
+static int
+mt7915_thermal_get_max_throttle_state(struct thermal_cooling_device *cdev,
+				      unsigned long *state)
+{
+	*state = MT7915_THERMAL_THROTTLE_MAX;
+
+	return 0;
+}
+
+static int
+mt7915_thermal_get_cur_throttle_state(struct thermal_cooling_device *cdev,
+				      unsigned long *state)
+{
+	struct mt7915_phy *phy = cdev->devdata;
+
+	*state = phy->throttle_state;
+
+	return 0;
+}
+
+static int
+mt7915_thermal_set_cur_throttle_state(struct thermal_cooling_device *cdev,
+				      unsigned long state)
+{
+	struct mt7915_phy *phy = cdev->devdata;
+	int ret;
+
+	if (state > MT7915_THERMAL_THROTTLE_MAX)
+		return -EINVAL;
+
+	if (state == phy->throttle_state)
+		return 0;
+
+	ret = mt7915_mcu_set_thermal_throttling(phy, state);
+	if (ret)
+		return ret;
+
+	phy->throttle_state = state;
+
+	return 0;
+}
+
+static const struct thermal_cooling_device_ops mt7915_thermal_ops = {
+	.get_max_state = mt7915_thermal_get_max_throttle_state,
+	.get_cur_state = mt7915_thermal_get_cur_throttle_state,
+	.set_cur_state = mt7915_thermal_set_cur_throttle_state,
+};
+
+static void mt7915_unregister_thermal(struct mt7915_phy *phy)
+{
+	struct wiphy *wiphy = phy->mt76->hw->wiphy;
+
+	if (!phy->cdev)
+	    return;
+
+	sysfs_remove_link(&wiphy->dev.kobj, "cooling_device");
+	thermal_cooling_device_unregister(phy->cdev);
+}
+
 static int mt7915_thermal_init(struct mt7915_phy *phy)
 {
 	struct wiphy *wiphy = phy->mt76->hw->wiphy;
+	struct thermal_cooling_device *cdev;
 	struct device *hwmon;
 
+	cdev = thermal_cooling_device_register(wiphy_name(wiphy), phy,
+					       &mt7915_thermal_ops);
+	if (!IS_ERR(cdev)) {
+		if (sysfs_create_link(&wiphy->dev.kobj, &cdev->device.kobj,
+				      "cooling_device") < 0)
+			thermal_cooling_device_unregister(cdev);
+		else
+			phy->cdev = cdev;
+	}
+
 	if (!IS_REACHABLE(CONFIG_HWMON))
 		return 0;
 
@@ -709,6 +780,7 @@ static void mt7915_unregister_ext_phy(struct mt7915_dev *dev)
 	if (!phy)
 		return;
 
+	mt7915_unregister_thermal(phy);
 	mt76_unregister_phy(mphy);
 	ieee80211_free_hw(mphy->hw);
 }
@@ -771,6 +843,7 @@ int mt7915_register_device(struct mt7915_dev *dev)
 void mt7915_unregister_device(struct mt7915_dev *dev)
 {
 	mt7915_unregister_ext_phy(dev);
+	mt7915_unregister_thermal(&dev->phy);
 	mt76_unregister_device(&dev->mt76);
 	mt7915_mcu_exit(dev);
 	mt7915_tx_token_put(dev);