From 0cc6fdfea69738c2696b3d1abfb0de77110a4919 Mon Sep 17 00:00:00 2001
From: agessaman <adam@gessaman.com>
Date: Thu, 20 Aug 2026 21:48:29 -0700
Subject: [PATCH] Add Heltec V4 R8 FEM LNA controls

---
 variants/heltec_v4_r8/HeltecV4R8Board.cpp | 18 ++++++++++++++++++
 variants/heltec_v4_r8/HeltecV4R8Board.h   |  3 +++
 variants/heltec_v4_r8/LoRaFEMControl.cpp  |  1 +
 variants/heltec_v4_r8/LoRaFEMControl.h    |  6 ++++--
 variants/heltec_v4_r8/platformio.ini      |  6 +++---
 5 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/variants/heltec_v4_r8/HeltecV4R8Board.cpp b/variants/heltec_v4_r8/HeltecV4R8Board.cpp
index 1fb123b2f..11aa9f64a 100644
--- a/variants/heltec_v4_r8/HeltecV4R8Board.cpp
+++ b/variants/heltec_v4_r8/HeltecV4R8Board.cpp
@@ -84,3 +84,21 @@ const char* HeltecV4R8Board::getManufacturerName() const {
   return "Heltec V4 R8 OLED";
 #endif
 }
+
+bool HeltecV4R8Board::setLoRaFemLnaEnabled(bool enable) {
+  if (!loRaFEMControl.isLnaCanControl()) {
+    return false;
+  }
+
+  loRaFEMControl.setLNAEnable(enable);
+  loRaFEMControl.setRxModeEnable();
+  return true;
+}
+
+bool HeltecV4R8Board::canControlLoRaFemLna() const {
+  return loRaFEMControl.isLnaCanControl();
+}
+
+bool HeltecV4R8Board::isLoRaFemLnaEnabled() const {
+  return loRaFEMControl.isLNAEnabled();
+}
diff --git a/variants/heltec_v4_r8/HeltecV4R8Board.h b/variants/heltec_v4_r8/HeltecV4R8Board.h
index 20811abb1..d8617b5b1 100644
--- a/variants/heltec_v4_r8/HeltecV4R8Board.h
+++ b/variants/heltec_v4_r8/HeltecV4R8Board.h
@@ -25,6 +25,9 @@ public:
   void onAfterTransmit(void) override;
   void enterDeepSleep(uint32_t secs, int pin_wake_btn = -1);
   void powerOff() override;
+  bool setLoRaFemLnaEnabled(bool enable) override;
+  bool canControlLoRaFemLna() const override;
+  bool isLoRaFemLnaEnabled() const override;
   uint16_t getBattMilliVolts() override;
   bool setAdcMultiplier(float multiplier) override {
     if (multiplier == 0.0f) {
diff --git a/variants/heltec_v4_r8/LoRaFEMControl.cpp b/variants/heltec_v4_r8/LoRaFEMControl.cpp
index bb530de3c..2d0feba64 100644
--- a/variants/heltec_v4_r8/LoRaFEMControl.cpp
+++ b/variants/heltec_v4_r8/LoRaFEMControl.cpp
@@ -21,6 +21,7 @@ void LoRaFEMControl::init(void) {
   digitalWrite(P_LORA_KCT8103L_PA_CSD, HIGH);
   pinMode(P_LORA_KCT8103L_PA_CTX, OUTPUT);
   digitalWrite(P_LORA_KCT8103L_PA_CTX, lna_enabled ? LOW : HIGH);
+  setLnaCanControl(true);
 }
 
 void LoRaFEMControl::setSleepModeEnable(void) {
diff --git a/variants/heltec_v4_r8/LoRaFEMControl.h b/variants/heltec_v4_r8/LoRaFEMControl.h
index 961cfd070..b55e15533 100644
--- a/variants/heltec_v4_r8/LoRaFEMControl.h
+++ b/variants/heltec_v4_r8/LoRaFEMControl.h
@@ -15,10 +15,12 @@ public:
   void setRxModeEnable(void);
   void setRxModeEnableWhenMCUSleep(void);
   void setLNAEnable(bool enabled);
-  bool isLnaCanControl(void) { return true; }
-  void setLnaCanControl(bool can_control) { }
+  bool isLnaCanControl(void) const { return lna_can_control; }
+  void setLnaCanControl(bool can_control) { lna_can_control = can_control; }
+  bool isLNAEnabled(void) const { return lna_enabled; }
   LoRaFEMType getFEMType(void) const { return KCT8103L_PA; }
 
 private:
   bool lna_enabled = false;
+  bool lna_can_control = false;
 };
diff --git a/variants/heltec_v4_r8/platformio.ini b/variants/heltec_v4_r8/platformio.ini
index 6f8d5a7f7..70e5f7029 100644
--- a/variants/heltec_v4_r8/platformio.ini
+++ b/variants/heltec_v4_r8/platformio.ini
@@ -17,9 +17,9 @@ build_flags =
   -D P_LORA_SCLK=9
   -D P_LORA_MISO=11
   -D P_LORA_MOSI=10
-  -D P_LORA_PA_POWER=7
-  -D P_LORA_KCT8103L_PA_CSD=2
-  -D P_LORA_KCT8103L_PA_CTX=5
+  -D P_LORA_PA_POWER=7  ; VFEM_Ctrl - LDO power enable
+  -D P_LORA_KCT8103L_PA_CSD=2  ; FEM_EN / CSD (HIGH=on)
+  -D P_LORA_KCT8103L_PA_CTX=5  ; PA_CTX (LOW=RX LNA, HIGH=RX bypass)
   -D P_LORA_TX_LED=46
   -D PIN_USER_BTN=0
   -D PIN_VEXT_EN=40