From 6fdf3feef73fd538fd47a1ffec3660738f3caa4b Mon Sep 17 00:00:00 2001
From: Marcin Czeczko <marcin.czeczko@gmail.com>
Date: Wed, 3 Mar 2021 12:40:23 +0100
Subject: [PATCH] [SX1278] Added method to control InvertIQ

---
 keywords.txt                  |  1 +
 src/modules/SX127x/SX1278.cpp | 16 ++++++++++++++++
 src/modules/SX127x/SX1278.h   | 13 +++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/keywords.txt b/keywords.txt
index e117eec2..fd9d2268 100644
--- a/keywords.txt
+++ b/keywords.txt
@@ -131,6 +131,7 @@ setRfSwitchPins	KEYWORD2
 forceLDRO	KEYWORD2
 autoLDRO	KEYWORD2
 getChipVersion	KEYWORD2
+invertIQ    KEYWORD2
 
 # RF69-specific
 setAESKey	KEYWORD2
diff --git a/src/modules/SX127x/SX1278.cpp b/src/modules/SX127x/SX1278.cpp
index f33af33a..8f43d52e 100644
--- a/src/modules/SX127x/SX1278.cpp
+++ b/src/modules/SX127x/SX1278.cpp
@@ -538,6 +538,22 @@ int16_t SX1278::setHeaderType(uint8_t headerType, size_t len) {
   return(state);
 }
 
+int16_t SX1278::invertIQ(bool invertIQ) {
+  // check active modem
+  if(getActiveModem() != SX127X_LORA) {
+    return(ERR_WRONG_MODEM);
+  }
+
+  int16_t state;
+  if(invertIQ) {
+    state = _mod->SPIsetRegValue(SX127X_REG_INVERT_IQ, SX127X_REG_INVERT_IQ_ON, 6, 6);
+  } else {
+    state = _mod->SPIsetRegValue(SX127X_REG_INVERT_IQ, SX127X_REG_INVERT_IQ_OFF, 6, 6);
+  }
+
+  return(state);
+}
+
 int16_t SX1278::configFSK() {
   // configure common registers
   int16_t state = SX127x::configFSK();
diff --git a/src/modules/SX127x/SX1278.h b/src/modules/SX127x/SX1278.h
index 438a9c18..b79eb244 100644
--- a/src/modules/SX127x/SX1278.h
+++ b/src/modules/SX127x/SX1278.h
@@ -66,6 +66,10 @@
 #define SX1278_AGC_AUTO_OFF                           0b00000000  //  2     2     LNA gain set by REG_LNA
 #define SX1278_AGC_AUTO_ON                            0b00000100  //  2     2     LNA gain set by internal AGC loop
 
+// SX127X_REG_INVERT_IQ
+#define SX127X_REG_INVERT_IQ_ON                       0b01000000  //  6     6     I and Q signals are inverted    
+#define SX127X_REG_INVERT_IQ_OFF                      0b00000000  //  6     6     normal mode
+
 // SX127X_REG_VERSION
 #define SX1278_CHIP_VERSION                           0x12
 
@@ -295,6 +299,15 @@ class SX1278: public SX127x {
     */
     int16_t explicitHeader();
 
+    /*!
+      \brief Enables/disables Invert the LoRa I and Q signals.
+
+      \param invertIQ Enable (true) or disable (false) LoRa I and Q signals.
+
+      \returns \ref status_codes
+    */
+    int16_t invertIQ(bool invertIQ);
+
 #ifndef RADIOLIB_GODMODE
   protected:
 #endif