Implement setting TX_GAIN_LORA for portduino

src/configuration.h

@@ -132,6 +132,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #endif
 
 // Default system gain to 0 if not defined
+#ifndef NUM_PA_POINTS
+#define NUM_PA_POINTS 1
+#endif
+
 #ifndef TX_GAIN_LORA
 #define TX_GAIN_LORA 0
 #endif

src/mesh/RadioInterface.cpp

@@ -646,26 +646,32 @@ void RadioInterface::limitPower(int8_t loraMaxPower)
         power = maxPower;
     }
 
-#ifndef NUM_PA_POINTS
-    if (TX_GAIN_LORA > 0 && !devicestate.owner.is_licensed) {
-        LOG_INFO("Requested Tx power: %d dBm; Device LoRa Tx gain: %d dB", power, TX_GAIN_LORA);
-        power -= TX_GAIN_LORA;
-    }
+#ifdef ARCH_PORTDUINO
+    size_t num_pa_points = portduino_config.num_pa_points;
+    const uint16_t *tx_gain = portduino_config.tx_gain_lora;
 #else
-    if (!devicestate.owner.is_licensed) {
+    size_t num_pa_points = NUM_PA_POINTS;
+    const uint16_t tx_gain[NUM_PA_POINTS] = {TX_GAIN_LORA};
+#endif
+
+    if (num_pa_points == 1) {
+        if (tx_gain[0] > 0 && !devicestate.owner.is_licensed) {
+            LOG_INFO("Requested Tx power: %d dBm; Device LoRa Tx gain: %d dB", power, tx_gain[0]);
+            power -= tx_gain[0];
+        }
+    } else if (!devicestate.owner.is_licensed) {
         // we have an array of PA gain values.  Find the highest power setting that works.
-        const uint16_t tx_gain[NUM_PA_POINTS] = {TX_GAIN_LORA};
-        for (int radio_dbm = 0; radio_dbm < NUM_PA_POINTS; radio_dbm++) {
+        for (int radio_dbm = 0; radio_dbm < num_pa_points; radio_dbm++) {
             if (((radio_dbm + tx_gain[radio_dbm]) > power) ||
-                ((radio_dbm == (NUM_PA_POINTS - 1)) && ((radio_dbm + tx_gain[radio_dbm]) <= power))) {
+                ((radio_dbm == (num_pa_points - 1)) && ((radio_dbm + tx_gain[radio_dbm]) <= power))) {
                 // we've exceeded the power limit, or hit the max we can do
                 LOG_INFO("Requested Tx power: %d dBm; Device LoRa Tx gain: %d dB", power, tx_gain[radio_dbm]);
                 power -= tx_gain[radio_dbm];
                 break;
             }
         }
     }
-#endif
+
     if (power > loraMaxPower) // Clamp power to maximum defined level
         power = loraMaxPower;
 

src/platform/portduino/PortduinoGlue.cpp

@@ -544,6 +544,19 @@ bool loadConfig(const char *configPath)
             if (yamlConfig["Lora"]["RF95_MAX_POWER"])
                 portduino_config.rf95_max_power = yamlConfig["Lora"]["RF95_MAX_POWER"].as<int>(20);
 
+            if (yamlConfig["Lora"]["TX_GAIN_LORA"]) {
+                YAML::Node tx_gain_node = yamlConfig["Lora"]["TX_GAIN_LORA"];
+                if (tx_gain_node.IsSequence() && tx_gain_node.size() != 0) {
+                    portduino_config.num_pa_points = min(tx_gain_node.size(), std::size(portduino_config.tx_gain_lora));
+                    for (int i = 0; i < portduino_config.num_pa_points; i++) {
+                        portduino_config.tx_gain_lora[i] = tx_gain_node[i].as<int>();
+                    }
+                } else {
+                    portduino_config.num_pa_points = 1;
+                    portduino_config.tx_gain_lora[0] = tx_gain_node.as<int>(0);
+                }
+            }
+
             if (portduino_config.lora_module != use_autoconf && portduino_config.lora_module != use_simradio &&
                 !portduino_config.force_simradio) {
                 portduino_config.dio2_as_rf_switch = yamlConfig["Lora"]["DIO2_AS_RF_SWITCH"].as<bool>(false);

src/platform/portduino/PortduinoGlue.h

@@ -87,6 +87,8 @@ extern struct portduino_config_struct {
     int lora_usb_pid = 0x5512;
     int lora_usb_vid = 0x1A86;
     int spiSpeed = 2000000;
+    int num_pa_points = 1; // default to 1 point, with 0 gain
+    uint16_t tx_gain_lora[22] = {0};
     pinMapping lora_cs_pin = {"Lora", "CS"};
     pinMapping lora_irq_pin = {"Lora", "IRQ"};
     pinMapping lora_busy_pin = {"Lora", "Busy"};
@@ -222,6 +224,17 @@ extern struct portduino_config_struct {
             out << YAML::Key << "LR1120_MAX_POWER" << YAML::Value << lr1120_max_power;
         if (rf95_max_power != 20)
             out << YAML::Key << "RF95_MAX_POWER" << YAML::Value << rf95_max_power;
+
+        if (num_pa_points > 1) {
+            out << YAML::Key << "TX_GAIN_LORA" << YAML::Value << YAML::Flow << YAML::BeginSeq;
+            for (int i = 0; i < num_pa_points; i++) {
+                out << YAML::Value << tx_gain_lora[i];
+            }
+            out << YAML::EndSeq;
+        } else if (tx_gain_lora[0] != 0) {
+            out << YAML::Key << "TX_GAIN_LORA" << YAML::Value << tx_gain_lora[0];
+        }
+
         out << YAML::Key << "DIO2_AS_RF_SWITCH" << YAML::Value << dio2_as_rf_switch;
         if (dio3_tcxo_voltage != 0)
             out << YAML::Key << "DIO3_TCXO_VOLTAGE" << YAML::Value << YAML::Precision(3) << (float)dio3_tcxo_voltage / 1000;