[PATCH v2] wifi: mt76: mt7996: add thermal zone device registration

[Ryan Leung]

Register the mt7996 phy as a thermal zone sensor using
devm_thermal_of_zone_register() so that device tree thermal-zones
nodes can reference the Wi-Fi chip as a temperature source. This
allows the kernel thermal governor to control external cooling
devices such as PWM fans based on Wi-Fi chip temperature.

Registration is non-fatal: -ENODEV is returned when no
thermal-sensors DT property references this device, which is the
expected case on platforms without a thermal zone configured.

Signed-off-by: Ryan Leung <untilscour at protonmail.com>
---
Changes in v2:
- Take phy->dev->mt76.mutex around mt7996_mcu_get_temperature()
- Unregister phy->tzone explicitly in mt7996_unregister_thermal() before the phy is freed
- Link to v1: https://patch.msgid.link/20260722-mt7996-thermal-zone-v1-1-88896e6e9985@protonmail.com

To: Felix Fietkau <nbd at nbd.name>
To: Lorenzo Bianconi <lorenzo at kernel.org>
To: Ryder Lee <ryder.lee at mediatek.com>
To: Shayne Chen <shayne.chen at mediatek.com>
To: Sean Wang <sean.wang at mediatek.com>
To: Matthias Brugger <matthias.bgg at gmail.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
Cc: linux-wireless at vger.kernel.org
Cc: linux-kernel at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-mediatek at lists.infradead.org
---
 drivers/net/wireless/mediatek/mt76/mt7996/init.c   | 33 ++++++++++++++++++++++
 drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h |  1 +
 2 files changed, 34 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/init.c b/drivers/net/wireless/mediatek/mt76/mt7996/init.c
index fb635a092584..fda9df1fa66b 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/init.c
@@ -234,11 +234,33 @@ static const struct thermal_cooling_device_ops mt7996_thermal_ops = {
 	.set_cur_state = mt7996_thermal_set_cur_throttle_state,
 };
 
+static int mt7996_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
+{
+	struct mt7996_phy *phy = thermal_zone_device_priv(tz);
+	int val;
+
+	mutex_lock(&phy->dev->mt76.mutex);
+	val = mt7996_mcu_get_temperature(phy);
+	mutex_unlock(&phy->dev->mt76.mutex);
+	if (val < 0)
+		return val;
+
+	*temp = val * 1000;
+	return 0;
+}
+
+static const struct thermal_zone_device_ops mt7996_tz_ops = {
+	.get_temp = mt7996_thermal_get_temp,
+};
+
 static void mt7996_unregister_thermal(struct mt7996_phy *phy)
 {
 	struct wiphy *wiphy = phy->mt76->hw->wiphy;
 	char name[sizeof("cooling_deviceXXX")];
 
+	if (phy->tzone)
+		devm_thermal_of_zone_unregister(phy->dev->mt76.dev, phy->tzone);
+
 	if (!phy->cdev)
 		return;
 
@@ -275,6 +297,17 @@ static int mt7996_thermal_init(struct mt7996_phy *phy)
 	phy->throttle_temp[MT7996_CRIT_TEMP_IDX] = MT7996_CRIT_TEMP;
 	phy->throttle_temp[MT7996_MAX_TEMP_IDX] = MT7996_MAX_TEMP;
 
+	phy->tzone = devm_thermal_of_zone_register(phy->dev->mt76.dev,
+						   phy->mt76->band_idx, phy,
+						   &mt7996_tz_ops);
+	if (IS_ERR(phy->tzone)) {
+		if (PTR_ERR(phy->tzone) != -ENODEV)
+			dev_warn(phy->dev->mt76.dev,
+				 "failed to register thermal zone %d: %ld\n",
+				 phy->mt76->band_idx, PTR_ERR(phy->tzone));
+		phy->tzone = NULL;
+	}
+
 	if (!IS_REACHABLE(CONFIG_HWMON))
 		return 0;
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h b/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
index 2a0cdb56f822..39fa25a562e5 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
@@ -372,6 +372,7 @@ struct mt7996_phy {
 
 	struct ieee80211_sband_iftype_data iftype[NUM_NL80211_BANDS][NUM_NL80211_IFTYPES];
 
+	struct thermal_zone_device *tzone;
 	struct thermal_cooling_device *cdev;
 	u8 cdev_state;
 	u8 throttle_state;

---
base-commit: ca800a9302764c445de0da0e84d2252400a770ee
change-id: 20260722-mt7996-thermal-zone-a1de7cb1d728

Best regards,
--  
Ryan Leung <untilscour at protonmail.com>