at86rf2xx: correct rssi

AT86RF231 MAN. p.89 8.3.2 Reading RSSI
AT86RF232 MAN. p.88 8.3.2 Reading RSSI
AT86RF233 MAN. p.99 8.4.2 Reading RSSI

"It is not recommended reading the RSSI value when using the Extended  Operating Modes, use ED instead"

drivers/at86rf2xx/at86rf2xx_netdev.c

@@ -166,18 +166,39 @@ static int _recv(netdev_t *netdev, void *buf, size_t len, void *info)
     at86rf2xx_fb_read(dev, tmp, 2);
     (void)tmp;
 
+    /* at86rf212  RSSI_BASE_VAL +3.1*RSSI, base varies for diff. modulation and datarates
+     * at86RF232  RSSI_BASE_VAL +3.0*RSSI, base -91dBm
+     * at86RF233  RSSI_BASE_VAL +3.0*RSSI, base -94dBm
+     * at86RF231  RSSI_BASE_VAL +3.0*(RSSI-1), base -91dBm
+     * at***RFR2  RSSI_BASE_VAL +3.0*(RSSI-1), base -90dBm
+     *
+     * AT86RF231 MAN. p.89 8.3.2 Reading RSSI
+     * AT86RF232 MAN. p.88 8.3.2 Reading RSSI
+     * AT86RF233 MAN. p.99 8.4.2 Reading RSSI
+     * "It is not recommended reading the RSSI value when using the Extended
+     * Operating Modes, use ED instead"
+     * at86RF231  RSSI_BASE_VAL +ED, base -90dBm
+     * at86RF232  RSSI_BASE_VAL +ED, base -91dBm
+     * at86RF233  RSSI_BASE_VAL +ED, base -94dBm
+     * at***RFR2  RSSI_BASE_VAL +ED, base -90dBm
+     */
     if (info != NULL) {
         uint8_t rssi = 0;
         netdev_ieee802154_rx_info_t *radio_info = info;
+
+#if defined(MODULE_AT86RF231) || defined(MODULE_AT86RF232) || defined(MODULE_AT86RF233)
         at86rf2xx_fb_read(dev, &(radio_info->lqi), 1);
-#ifndef MODULE_AT86RF231
-        at86rf2xx_fb_read(dev, &(rssi), 1);
         at86rf2xx_fb_stop(dev);
+        rssi = at86rf2xx_reg_read(dev, AT86RF2XX_REG__PHY_ED_LEVEL);
 #else
+        at86rf2xx_fb_read(dev, &(radio_info->lqi), 1);
+        at86rf2xx_fb_read(dev, &(rssi), 1);
         at86rf2xx_fb_stop(dev);
-        rssi = at86rf2xx_reg_read(dev, AT86RF2XX_REG__PHY_ED_LEVEL);
+        rssi = 3 * rssi;
 #endif
         radio_info->rssi = RSSI_BASE_VAL + rssi;
+        DEBUG("[at86rf2xx] LQI:%d high is good, RSSI:%d high is either good or"
+              "too much interference.\n", radio_info->lqi, radio_info->rssi);
     }
     else {
         at86rf2xx_fb_stop(dev);