[PATCH 4.20 110/117] mt76x0: do not overwrite other MT_BBP(AGC, 8) fields

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>

commit b983a5b900627faa49cf37e101d65b56e941c740 upstream.

MT_BBP(AGC, 8) register has values depend on band in
mt76x0_bbp_switch_tab, so we should not overwrite other fields
than MT_BBP_AGC_GAIN when setting gain.

This can fix performance issues when connecting to 2.4GHz AP.

Fixes: 4636a2544c3b ("mt76x0: phy: align channel gain logic to mt76x2 one")
Acked-by: Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>
Signed-off-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>


---
 drivers/net/wireless/mediatek/mt76/mt76x0/phy.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/drivers/net/wireless/mediatek/mt76/mt76x0/phy.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x0/phy.c
@@ -817,10 +817,8 @@ done:
 static void mt76x0_phy_set_gain_val(struct mt76x02_dev *dev)
 {
 	u8 gain = dev->cal.agc_gain_cur[0] - dev->cal.agc_gain_adjust;
-	u32 val = 0x122c << 16 | 0xf2;
 
-	mt76_wr(dev, MT_BBP(AGC, 8),
-		val | FIELD_PREP(MT_BBP_AGC_GAIN, gain));
+	mt76_rmw_field(dev, MT_BBP(AGC, 8), MT_BBP_AGC_GAIN, gain);
 }
 
 static void