Add support for Adafruit Feather RP2040 with RFM95. (meshtastic#4451)

* Add support for Adafruit Feather RP2040 with RFM95.

* Update mesh.pb.h

dropping this change from the file generated by the protobuf

* Update mesh.pb.h

remove these reverting changes

* Update mesh.pb.h

oops, missed a comma

src/platform/rp2040/architecture.h

@@ -29,4 +29,6 @@
 #define HW_VENDOR meshtastic_HardwareModel_SENSELORA_RP2040
 #elif defined(RP2040_LORA)
 #define HW_VENDOR meshtastic_HardwareModel_RP2040_LORA
+#elif defined(RP2040_FEATHER_RFM95)
+#define HW_VENDOR meshtastic_HardwareModel_RP2040_FEATHER_RFM95
 #endif

variants/feather_rp2040_rfm95/platformio.ini

@@ -0,0 +1,16 @@
+[env:feather_rp2040_rfm95]
+extends = rp2040_base
+board = adafruit_feather
+upload_protocol = picotool
+
+# add our variants files to the include and src paths
+build_flags = ${rp2040_base.build_flags} 
+  -DRP2040_FEATHER_RFM95
+  -Ivariants/feather_rp2040_rfm95
+  -DDEBUG_RP2040_PORT=Serial
+  -DHW_SPI1_DEVICE
+  -L "${platformio.libdeps_dir}/${this.__env__}/bsec2/src/cortex-m0plus"
+lib_deps =
+  ${rp2040_base.lib_deps}
+debug_build_flags = ${rp2040_base.build_flags}
+debug_tool = cmsis-dap ; for e.g. Picotool

variants/feather_rp2040_rfm95/variant.h

@@ -0,0 +1,61 @@
+// #define RADIOLIB_CUSTOM_ARDUINO 1
+// #define RADIOLIB_TONE_UNSUPPORTED 1
+// #define RADIOLIB_SOFTWARE_SERIAL_UNSUPPORTED 1
+
+#define ARDUINO_ARCH_AVR
+
+// #define USE_SSD1306
+
+// #define USE_SH1106 1
+
+// default I2C pins:
+// SDA = 4
+// SCL = 5
+
+// Recommended pins for SerialModule:
+// txd = 8
+// rxd = 9
+
+#define EXT_NOTIFY_OUT 22
+#define BUTTON_PIN 7
+// #define BUTTON_NEED_PULLUP
+
+#define LED_PIN PIN_LED
+
+// #define BATTERY_PIN 26
+//  ratio of voltage divider = 3.0 (R17=200k, R18=100k)
+// #define ADC_MULTIPLIER 3.1 // 3.0 + a bit for being optimistic
+
+#define USE_RF95 // RFM95/SX127x
+
+#undef LORA_SCK
+#undef LORA_MISO
+#undef LORA_MOSI
+#undef LORA_CS
+
+// https://www.adafruit.com/product/5714
+// https://learn.adafruit.com/feather-rp2040-rfm95
+// https://learn.adafruit.com/assets/120283
+// https://learn.adafruit.com/assets/120813
+#define LORA_SCK 14  // 10 12P
+#define LORA_MISO 8  // 12 10P
+#define LORA_MOSI 15 // 11 11P
+#define LORA_CS 16   // 3 13P
+
+#define LORA_RESET 17 // 15 14P
+
+#define LORA_DIO0 21 // ?? 6P
+#define LORA_DIO1 22 // 20 7P
+#define LORA_DIO2 23 // 2 8P
+#define LORA_DIO3 19 // ?? 3P
+#define LORA_DIO4 20 // ?? 4P
+#define LORA_DIO5 18 // ?? 15P
+
+#ifdef USE_SX1262
+#define SX126X_CS LORA_CS
+#define SX126X_DIO1 LORA_DIO1
+#define SX126X_BUSY LORA_DIO2
+#define SX126X_RESET LORA_RESET
+#define SX126X_DIO2_AS_RF_SWITCH
+// #define SX126X_DIO3_TCXO_VOLTAGE 1.8
+#endif