From da0cd455c93f31fe10910c65979190feffb4c822 Mon Sep 17 00:00:00 2001
From: Robert <3704942+JasonRJ@users.noreply.github.com>
Date: Wed, 23 Feb 2022 23:58:56 -0500
Subject: [PATCH] Add method to support SX128x Manual Gain Mode.

---
 src/modules/SX128x/SX128x.cpp | 33 +++++++++++++++++++++++++++++++++
 src/modules/SX128x/SX128x.h   |  9 +++++++++
 2 files changed, 42 insertions(+)

diff --git a/src/modules/SX128x/SX128x.cpp b/src/modules/SX128x/SX128x.cpp
index 9316eae2..a9241716 100644
--- a/src/modules/SX128x/SX128x.cpp
+++ b/src/modules/SX128x/SX128x.cpp
@@ -1035,6 +1035,39 @@ int16_t SX128x::setHighSensitivityMode(bool hsm) {
     return(0);
 }
 
+int16_t SX128x::setGainControl(uint8_t gain) {
+    // update registers
+    uint8_t ManualGainSetting = 0;
+    int16_t state = readRegister(RADIOLIB_SX128X_REG_MANUAL_GAIN_CONTROL_ENABLE_2, &ManualGainSetting, 1);
+    RADIOLIB_ASSERT(state);
+    uint8_t LNAGainValue = 0;
+    state = readRegister(RADIOLIB_SX128X_REG_MANUAL_GAIN_SETTING, &LNAGainValue, 1);
+    RADIOLIB_ASSERT(state);
+    uint8_t LNAGainControl = 0;
+    state = readRegister(RADIOLIB_SX128X_REG_MANUAL_GAIN_CONTROL_ENABLE_1, &LNAGainControl, 1);
+    RADIOLIB_ASSERT(state);
+    if (gain > 0 && gain < 14) {
+        // Set manual gain
+        ManualGainSetting &= ~0x01; // Set bit 0 to 0 (Enable Manual Gain Control)
+        LNAGainValue &= 0xF0; // Bits 0, 1, 2 and 3 to 0
+        LNAGainValue |= gain; // Set bits 0, 1, 2 and 3 to Manual Gain Setting (1-13)
+        LNAGainControl |= 0x80; // Set bit 7 to 1 (Enable Manual Gain Control)
+    } else {
+        // Set automatic gain if 0 or out of range
+        ManualGainSetting |= 0x01; // Set bit 0 to 1 (Enable Automatic Gain Control)
+        LNAGainValue &= 0xF0; // Bits 0, 1, 2 and 3 to 0
+        LNAGainValue |= 0x0A; // Set bits 0, 1, 2 and 3 to Manual Gain Setting (1-13)
+        LNAGainControl = 0x4D; // Set bit 7 to 0 (Enable Automatic Gain Control)
+    }
+    state = writeRegister(RADIOLIB_SX128X_REG_MANUAL_GAIN_CONTROL_ENABLE_2, &ManualGainSetting, 1);
+    RADIOLIB_ASSERT(state);
+    state = writeRegister(RADIOLIB_SX128X_REG_MANUAL_GAIN_SETTING, &LNAGainValue, 1);
+    RADIOLIB_ASSERT(state);
+    state = writeRegister(RADIOLIB_SX128X_REG_MANUAL_GAIN_CONTROL_ENABLE_1, &LNAGainControl, 1);
+    RADIOLIB_ASSERT(state);
+    return(0);
+}
+
 float SX128x::getRSSI() {
   // get packet status
   uint8_t packetStatus[5];
diff --git a/src/modules/SX128x/SX128x.h b/src/modules/SX128x/SX128x.h
index 5c18d6d1..2537fe43 100644
--- a/src/modules/SX128x/SX128x.h
+++ b/src/modules/SX128x/SX128x.h
@@ -722,6 +722,15 @@ class SX128x: public PhysicalLayer {
 */
     int16_t setHighSensitivityMode(bool hsm = false);
 
+    /*!
+      \brief Enables or disables receiver manual gain control.
+
+      \param Gain 0 automatic gain; 1 minimum gain to 13 maximum gain.
+
+      \returns \ref status_codes
+    */
+    int16_t setGainControl(uint8_t gain = 0);
+
     /*!
       \brief Gets RSSI (Recorded Signal Strength Indicator) of the last received packet.