mt76x02: assure we update gain after scan

Assure that after we initialize dev->cal.low_gain to -1 this
will cause update gain calibration. Otherwise this might or
might not happen depending on value of second bit of low_gain
and values read from registers in mt76x02_phy_adjust_vga_gain().
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76x0/phy.c

@@ -1082,7 +1082,8 @@ mt76x0_phy_update_channel_gain(struct mt76x02_dev *dev)
 	low_gain = (dev->cal.avg_rssi_all > mt76x02_get_rssi_gain_thresh(dev)) +
 		   (dev->cal.avg_rssi_all > mt76x02_get_low_rssi_gain_thresh(dev));
 
-	gain_change = (dev->cal.low_gain & 2) ^ (low_gain & 2);
+	gain_change = dev->cal.low_gain < 0 ||
+		      (dev->cal.low_gain & 2) ^ (low_gain & 2);
 	dev->cal.low_gain = low_gain;
 
 	if (!gain_change) {

drivers/net/wireless/mediatek/mt76/mt76x02_util.c

@@ -555,8 +555,11 @@ void mt76x02_sw_scan_complete(struct ieee80211_hw *hw,
 	if (mt76_is_mmio(dev))
 		tasklet_enable(&dev->pre_tbtt_tasklet);
 
-	if (dev->cal.gain_init_done)
+	if (dev->cal.gain_init_done) {
+		/* Restore AGC gain and resume calibration after scanning. */
+		dev->cal.low_gain = -1;
 		ieee80211_queue_delayed_work(hw, &dev->cal_work, 0);
+	}
 }
 EXPORT_SYMBOL_GPL(mt76x02_sw_scan_complete);
 

drivers/net/wireless/mediatek/mt76/mt76x2/phy.c

@@ -289,7 +289,8 @@ void mt76x2_phy_update_channel_gain(struct mt76x02_dev *dev)
 	low_gain = (dev->cal.avg_rssi_all > mt76x02_get_rssi_gain_thresh(dev)) +
 		   (dev->cal.avg_rssi_all > mt76x02_get_low_rssi_gain_thresh(dev));
 
-	gain_change = (dev->cal.low_gain & 2) ^ (low_gain & 2);
+	gain_change = dev->cal.low_gain < 0 ||
+		      (dev->cal.low_gain & 2) ^ (low_gain & 2);
 	dev->cal.low_gain = low_gain;
 
 	if (!gain_change) {