feat(variants): add Waveshare ESP32-S3-LR1121

ESP32-S3FH4R2 (4MB flash, 2MB PSRAM, native USB-CDC) with an LR1121.
Pins, the DIO5/DIO6 RF switch table and the 1.8 V TCXO follow the HF
schematic and Waveshare's examples. Envs: repeater, room server,
companion USB/BLE and KISS modem, all on min_spiffs so roles share one
partition layout.

Only RFO_HP_LF is wired (R4 on RFO_LP_LF is not fitted), so the new
opt-in LR1121_FORCE_HP_PA flag keeps RadioLib on the HP PA at <= 14 dBm,
where it would otherwise select the unconnected LP PA.

src/helpers/radiolib/CustomLR1121.h

@@ -36,6 +36,13 @@ class CustomLR1121 : public LR1121 {
       return len;
     }
     
+#ifdef LR1121_FORCE_HP_PA
+    // boards with only RFO_HP_LF wired: stop RadioLib switching to the LP PA at <= 14 dBm (2.4 GHz still uses the HF PA)
+    int16_t setOutputPower(int8_t power) override {
+      return LR1121::setOutputPower(power, true);
+    }
+#endif
+
     float getFreqMHz() const { return freqMHz; }
 
     int16_t setRxBoostedGainMode(bool en) {

variants/waveshare_esp32s3_lr1121/WaveshareS3LR1121Board.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <Arduino.h>
+#include <helpers/ESP32Board.h>
+
+class WaveshareS3LR1121Board : public ESP32Board {
+public:
+  const char* getManufacturerName() const override {
+    return "Waveshare ESP32-S3-LR1121";
+  }
+};

variants/waveshare_esp32s3_lr1121/platformio.ini

@@ -0,0 +1,102 @@
+; Waveshare ESP32-S3-LR1121 (HF: 850-930 MHz + 2.4 GHz)
+; ESP32-S3FH4R2 (4MB flash, 2MB PSRAM), native USB-CDC via the Tiny-Adapter FPC.
+; No user LED, battery sense or user button (BOOT is GPIO0).
+[Waveshare_S3_LR1121]
+extends = esp32_base
+board = esp32-s3-zero
+; min_spiffs: 1.9MB OTA app slots; one layout for every role so switching roles keeps the filesystem
+board_build.partitions = min_spiffs.csv
+build_flags = ${esp32_base.build_flags}
+  -I variants/waveshare_esp32s3_lr1121
+  -D BOARD_HAS_PSRAM
+  -D P_LORA_DIO_1=38
+  -D P_LORA_NSS=42
+  -D P_LORA_RESET=39
+  -D P_LORA_BUSY=41
+  -D P_LORA_SCLK=40
+  -D P_LORA_MISO=46
+  -D P_LORA_MOSI=45
+  -D RADIO_CLASS=CustomLR1121
+  -D WRAPPER_CLASS=CustomLR1121Wrapper
+  -D LR11X0_DIO3_TCXO_VOLTAGE=1.8
+  -D LR1121_FORCE_HP_PA   ; RFO_LP_LF is not fitted (R4 NC)
+  -D RX_BOOSTED_GAIN=true
+  -D LORA_TX_POWER=22
+build_src_filter = ${esp32_base.build_src_filter}
+  +<../variants/waveshare_esp32s3_lr1121>
+lib_deps =
+  ${esp32_base.lib_deps}
+
+[env:Waveshare_S3_LR1121_repeater]
+extends = Waveshare_S3_LR1121
+build_flags =
+  ${Waveshare_S3_LR1121.build_flags}
+  -D ADVERT_NAME='"Waveshare LR1121 Repeater"'
+  -D ADVERT_LAT=0.0
+  -D ADVERT_LON=0.0
+  -D ADMIN_PASSWORD='"password"'
+  -D MAX_NEIGHBOURS=50
+;  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+build_src_filter = ${Waveshare_S3_LR1121.build_src_filter}
+  +<../examples/simple_repeater/*.cpp>
+lib_deps =
+  ${Waveshare_S3_LR1121.lib_deps}
+  ${esp32_ota.lib_deps}
+
+[env:Waveshare_S3_LR1121_room_server]
+extends = Waveshare_S3_LR1121
+build_flags =
+  ${Waveshare_S3_LR1121.build_flags}
+  -D ADVERT_NAME='"Waveshare LR1121 Room"'
+  -D ADVERT_LAT=0.0
+  -D ADVERT_LON=0.0
+  -D ADMIN_PASSWORD='"password"'
+  -D ROOM_PASSWORD='"hello"'
+;  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+build_src_filter = ${Waveshare_S3_LR1121.build_src_filter}
+  +<../examples/simple_room_server>
+lib_deps =
+  ${Waveshare_S3_LR1121.lib_deps}
+  ${esp32_ota.lib_deps}
+
+[env:Waveshare_S3_LR1121_companion_radio_usb]
+extends = Waveshare_S3_LR1121
+build_flags =
+  ${Waveshare_S3_LR1121.build_flags}
+  -D MAX_CONTACTS=350
+  -D MAX_GROUP_CHANNELS=40
+  -D OFFLINE_QUEUE_SIZE=256
+  -D ENABLE_USB_INTERFACE
+;  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+build_src_filter = ${Waveshare_S3_LR1121.build_src_filter}
+  +<helpers/esp32/*.cpp>
+  +<../examples/companion_radio/*.cpp>
+lib_deps =
+  ${Waveshare_S3_LR1121.lib_deps}
+  densaugeo/base64 @ ~1.4.0
+
+[env:Waveshare_S3_LR1121_companion_radio_ble]
+extends = Waveshare_S3_LR1121
+build_flags =
+  ${Waveshare_S3_LR1121.build_flags}
+  -D MAX_CONTACTS=350
+  -D MAX_GROUP_CHANNELS=40
+  -D OFFLINE_QUEUE_SIZE=256
+  -D BLE_PIN_CODE=123456
+;  -D BLE_DEBUG_LOGGING=1
+;  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+build_src_filter = ${Waveshare_S3_LR1121.build_src_filter}
+  +<helpers/esp32/*.cpp>
+  +<../examples/companion_radio/*.cpp>
+lib_deps =
+  ${Waveshare_S3_LR1121.lib_deps}
+  densaugeo/base64 @ ~1.4.0
+
+[env:Waveshare_S3_LR1121_kiss_modem]
+extends = Waveshare_S3_LR1121
+build_src_filter = ${Waveshare_S3_LR1121.build_src_filter}
+  +<../examples/kiss_modem/>

variants/waveshare_esp32s3_lr1121/target.cpp

@@ -0,0 +1,63 @@
+#include <Arduino.h>
+#include "target.h"
+
+WaveshareS3LR1121Board board;
+
+static SPIClass spi;
+RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi);
+WRAPPER_CLASS radio_driver(radio, board);
+
+ESP32RTCClock fallback_clock;
+AutoDiscoverRTCClock rtc_clock(fallback_clock);
+SensorManager sensors;
+
+#ifndef LORA_CR
+  #define LORA_CR 5
+#endif
+
+// DIO5/DIO6 drive the RTC6603SP sub-GHz T/R switch; the 2.4 GHz port (RFIO_HF) is unswitched
+static const uint32_t rfswitch_dios[Module::RFSWITCH_MAX_PINS] = {
+  RADIOLIB_LR11X0_DIO5,
+  RADIOLIB_LR11X0_DIO6,
+  RADIOLIB_NC
+};
+
+static const Module::RfSwitchMode_t rfswitch_table[] = {
+  // mode                 DIO5  DIO6
+  { LR11x0::MODE_STBY,   {LOW,  LOW}},
+  { LR11x0::MODE_RX,     {HIGH, LOW}},
+  { LR11x0::MODE_TX,     {LOW,  HIGH}},
+  { LR11x0::MODE_TX_HP,  {LOW,  HIGH}},
+  { LR11x0::MODE_TX_HF,  {LOW,  LOW}},
+  { LR11x0::MODE_GNSS,   {LOW,  LOW}},
+  { LR11x0::MODE_WIFI,   {LOW,  LOW}},
+  END_OF_MODE_TABLE,
+};
+
+bool radio_init() {
+  fallback_clock.begin();
+  rtc_clock.begin(Wire);
+
+  spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI);
+  int status = radio.begin(LORA_FREQ, LORA_BW, LORA_SF, LORA_CR, RADIOLIB_LR11X0_LORA_SYNC_WORD_PRIVATE,
+                           LORA_TX_POWER, 16, LR11X0_DIO3_TCXO_VOLTAGE);
+  if (status != RADIOLIB_ERR_NONE) {
+    Serial.print("ERROR: radio init failed: ");
+    Serial.println(status);
+    return false;
+  }
+
+  radio.setCRC(2);
+  radio.explicitHeader();
+  radio.setRfSwitchTable(rfswitch_dios, rfswitch_table);
+#ifdef RX_BOOSTED_GAIN
+  radio.setRxBoostedGainMode(RX_BOOSTED_GAIN);
+#endif
+
+  return true;
+}
+
+mesh::LocalIdentity radio_new_identity() {
+  RadioNoiseListener rng(radio);
+  return mesh::LocalIdentity(&rng);
+}

variants/waveshare_esp32s3_lr1121/target.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#define RADIOLIB_STATIC_ONLY 1
+#include <RadioLib.h>
+#include <helpers/radiolib/RadioLibWrappers.h>
+#include <helpers/radiolib/CustomLR1121Wrapper.h>
+#include <helpers/AutoDiscoverRTCClock.h>
+#include <helpers/SensorManager.h>
+#include "WaveshareS3LR1121Board.h"
+
+extern WaveshareS3LR1121Board board;
+extern WRAPPER_CLASS radio_driver;
+extern AutoDiscoverRTCClock rtc_clock;
+extern SensorManager sensors;
+
+bool radio_init();
+mesh::LocalIdentity radio_new_identity();