[beken-72xx] Scan networks before connecting, if needed

arduino/beken-72xx/libraries/WiFi/WiFiData.h

@@ -14,6 +14,7 @@ extern "C" {
 typedef struct {
 	char ssid[32 + 1];
 	char pass[64 + 1];
+	unsigned long scannedAt;
 	uint32_t ipSta[4];
 	uint32_t ipAp[4];
 	SemaphoreHandle_t scanSem;

arduino/beken-72xx/libraries/WiFi/WiFiSTA.cpp

@@ -56,7 +56,11 @@ bool WiFiClass::reconnect(const uint8_t *bssid) {
 		goto error;
 	}
 
-	LT_D_WG("Connecting to " MACSTR, MAC2STR(bssid));
+	if (bssid) {
+		LT_D_WG("Connecting to " MACSTR, MAC2STR(bssid));
+	} else {
+		LT_D_WG("Connecting to %s", data.ssid);
+	}
 
 	network_InitTypeDef_st config;
 	memset(&config, 0, sizeof(network_InitTypeDef_st));
@@ -92,6 +96,13 @@ bool WiFiClass::reconnect(const uint8_t *bssid) {
 		LT_D_WG("Static DNS: %s", config.dns_server_ip_addr);
 	}
 
+	if (!data.scannedAt || millis() - data.scannedAt > 10000) {
+		LT_D_WG("Scan needed");
+		// apparently a scan must be performed first,
+		// else it hangs at "[sa_sta]MM_START_REQ"
+		scanNetworks(false);
+	}
+
 	LT_D_WG("Starting WiFi...");
 	__wrap_bk_printf_disable();
 	bk_wlan_start_sta(&config);

arduino/beken-72xx/libraries/WiFi/WiFiScan.cpp

@@ -36,6 +36,8 @@ static void scanHandler(void *ctx, uint8_t param) {
 		memcpy(scan->ap[i].bssid.addr, result.ApList[i].bssid, 6);
 	}
 
+	cls->data.scannedAt = millis();
+
 end:
 	scan->running = false;
 	xSemaphoreGive(cls->data.scanSem);