Adjust gain before scanning

- This patch temporarily increases the rx gain before scanning and reset
  it back to the last recorded value once the scanning finishes.
- Ref: #337

Author: Martin Hrůza

main.c

@@ -1571,6 +1571,8 @@ void rtw_core_scan_start(struct rtw_dev *rtwdev, struct rtw_vif *rtwvif,
 
 	set_bit(RTW_FLAG_DIG_DISABLE, rtwdev->flags);
 	set_bit(RTW_FLAG_SCANNING, rtwdev->flags);
+
+	rtw_phy_dig_set_max_coverage(rtwdev);
 }
 
 void rtw_core_scan_complete(struct rtw_dev *rtwdev, struct ieee80211_vif *vif,
@@ -1582,6 +1584,7 @@ void rtw_core_scan_complete(struct rtw_dev *rtwdev, struct ieee80211_vif *vif,
 	if (!rtwvif)
 		return;
 
+	rtw_phy_dig_reset(rtwdev);
 	clear_bit(RTW_FLAG_SCANNING, rtwdev->flags);
 	clear_bit(RTW_FLAG_DIG_DISABLE, rtwdev->flags);
 

phy.c

@@ -372,6 +372,21 @@ static void rtw_phy_statistics(struct rtw_dev *rtwdev)
 #define DIG_CVRG_MIN				0x1c
 #define DIG_RSSI_GAIN_OFFSET			15
 
+void rtw_phy_dig_set_max_coverage(struct rtw_dev *rtwdev) {
+	rtw_dbg(rtwdev, RTW_DBG_PHY, "Setting IGI to max coverage\n");
+	rtw_phy_dig_write(rtwdev, DIG_CVRG_MAX);
+}
+
+void rtw_phy_dig_reset(struct rtw_dev *rtwdev) {
+	struct rtw_dm_info *dm_info = &rtwdev->dm_info;
+	u8 last_igi;
+
+	last_igi = dm_info->igi_history[0];
+	rtw_dbg(rtwdev, RTW_DBG_PHY, "Resetting IGI=%u\n", last_igi);
+
+	rtw_phy_dig_write(rtwdev, last_igi);
+}
+
 static bool
 rtw_phy_dig_check_damping(struct rtw_dm_info *dm_info)
 {

phy.h

@@ -146,6 +146,8 @@ static inline int rtw_check_supported_rfe(struct rtw_dev *rtwdev)
 }
 
 void rtw_phy_dig_write(struct rtw_dev *rtwdev, u8 igi);
+void rtw_phy_dig_reset(struct rtw_dev *rtwdev);
+void rtw_phy_dig_set_max_coverage(struct rtw_dev *rtwdev);
 
 struct rtw_power_params {
 	u8 pwr_base;