[PATCH 4.20.x 1/7] mt76x0: do not overwrite other MT_BBP(AGC, 8) fields

[Stanislaw Gruszka]

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.bianc...@redhat.com>
Signed-off-by: Felix Fietkau <n...@nbd.name>
Signed-off-by: Stanislaw Gruszka <sgrus...@redhat.com>
---
 drivers/net/wireless/mediatek/mt76/mt76x0/phy.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76x0/phy.c 
b/drivers/net/wireless/mediatek/mt76/mt76x0/phy.c
index cf024950e0ed..1af2a1227924 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x0/phy.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x0/phy.c
@@ -817,10 +817,8 @@ static void mt76x0_temp_sensor(struct mt76x02_dev *dev)
 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
-- 
1.9.3