Fix unsigned conversion of negative TX power in CommonRadioPrefs

examples/companion_radio/NodePrefs.h

@@ -102,8 +102,8 @@ private:
     void setIntThresh(uint8_t t) override { _parent->interference_threshold = t; markDirty(); }
     uint8_t getRxGain() const override { return _parent->rx_boosted_gain; }
     void setRxGain(uint8_t g) override { _parent->rx_boosted_gain = g; markDirty(); }
-    uint8_t getTxPower() const override { return _parent->tx_power_dbm; }
-    void setTxPower(uint8_t dbm) override { _parent->tx_power_dbm = dbm; markDirty(); }
+    int8_t getTxPower() const override { return _parent->tx_power_dbm; }
+    void setTxPower(int8_t dbm) override { _parent->tx_power_dbm = dbm; markDirty(); }
     float getRxDelay() const override { return _parent->rx_delay_base; }
     void setRxDelay(float d) override { _parent->rx_delay_base = d; markDirty(); }
     uint16_t getAgcResetInt() const override { return _parent->agc_reset_interval * 4; }

src/helpers/CommonCLI.h

@@ -115,8 +115,8 @@ private:
     void setIntThresh(uint8_t t) override { _parent->interference_threshold = t; markDirty(); }
     uint8_t getRxGain() const override { return _parent->rx_boosted_gain; }
     void setRxGain(uint8_t g) override { _parent->rx_boosted_gain = g; markDirty(); }
-    uint8_t getTxPower() const override { return _parent->tx_power_dbm; }
-    void setTxPower(uint8_t dbm) override { _parent->tx_power_dbm = dbm; markDirty(); }
+    int8_t getTxPower() const override { return _parent->tx_power_dbm; }
+    void setTxPower(int8_t dbm) override { _parent->tx_power_dbm = dbm; markDirty(); }
     float getRxDelay() const override { return _parent->rx_delay_base; }
     void setRxDelay(float d) override { _parent->rx_delay_base = d; markDirty(); }
     uint16_t getAgcResetInt() const override { return _parent->agc_reset_interval * 4; }

src/helpers/CommonRadioPrefs.h

@@ -35,8 +35,8 @@ public:
   virtual uint8_t getRxGain() const = 0;
   virtual void setRxGain(uint8_t g) = 0;
 
-  virtual uint8_t getTxPower() const = 0;
-  virtual void setTxPower(uint8_t dbm) = 0;
+  virtual int8_t getTxPower() const = 0;
+  virtual void setTxPower(int8_t dbm) = 0;
 
   virtual float getRxDelay() const = 0;
   virtual void setRxDelay(float d) = 0;

test/test_companion_node_prefs/test_companion_node_prefs.cpp

@@ -6,6 +6,32 @@
 
 #include "../../examples/companion_radio/NodePrefs.h"
 
+bool CommonRadioPrefs::getByKey(const char* key, char* value, size_t max_len) {
+  if (strcmp(key, "fem_rxgain") == 0) {
+    snprintf(value, max_len, "%d", (uint32_t)getFEMRxGain());
+    return true;
+  }
+  if (strcmp(key, "fem_txgain") == 0) {
+    snprintf(value, max_len, "%d", (uint32_t)getFEMTxGain());
+    return true;
+  }
+  return false;
+}
+
+bool CommonRadioPrefs::setByKey(const char* key, const char* value) {
+  if (strcmp(key, "fem_rxgain") == 0) {
+    setFEMRxGain(atoi(value));
+    markDirty();
+    return true;
+  }
+  if (strcmp(key, "fem_txgain") == 0) {
+    setFEMTxGain(atoi(value));
+    markDirty();
+    return true;
+  }
+  return false;
+}
+
 class ReplayStream : public Stream {
   const char* _text;
   int _pos = 0;
@@ -77,6 +103,37 @@ TEST(CompanionNodePrefs, RxGainSettingsRoundTripIndependently) {
 }
 #endif
 
+TEST(CompanionNodePrefs, NegativeTxPowerPreservedAsSigned) {
+  NodePrefs prefs;
+  CommonRadioPrefs* radio = prefs.getRadioPrefs();
+
+  radio->setTxPower(-9);
+  EXPECT_EQ(-9, prefs.tx_power_dbm);
+  EXPECT_EQ(-9, radio->getTxPower());
+  EXPECT_EQ(-9, static_cast<int32_t>(radio->getTxPower()));
+
+  char reply[32];
+  snprintf(reply, sizeof(reply), "> %d", static_cast<int32_t>(radio->getTxPower()));
+  EXPECT_STREQ("> -9", reply);
+}
+
+TEST(CompanionNodePrefs, NegativeTxPowerRoundTripsSerial) {
+  NodePrefs saved;
+  saved.getRadioPrefs()->setTxPower(-9);
+
+  CaptureStream output;
+  ASSERT_TRUE(saved.saveSerial(output));
+  EXPECT_NE(std::string::npos, output.text().find("tx:-9"));
+
+  ReplayStream input("{radio:{tx:-9}}");
+  NodePrefs loaded;
+  loaded.tx_power_dbm = 22;
+
+  ASSERT_TRUE(loaded.loadSerial(input));
+  EXPECT_EQ(-9, loaded.tx_power_dbm);
+  EXPECT_EQ(-9, loaded.getRadioPrefs()->getTxPower());
+}
+
 int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();