Support for muzi works R1 Neo device.

Support for R1 Neo hardware. New variant and baseboard class.
* Known issues:
  - power management is not currently supported
  - power off via long button press is not implemented

Add support for Epson Seiko RX8130CE I2C Real-time clock.

variants/muziworks_r1_neo/R1NeoBoard.cpp

@@ -0,0 +1,65 @@
+#include <Arduino.h>
+#include <Wire.h>
+
+#include "R1NeoBoard.h"
+
+#ifdef NRF52_POWER_MANAGEMENT
+// Static configuration for power management
+// Values set in variant.h defines
+const PowerMgtConfig power_config = {
+  .lpcomp_ain_channel = PWRMGT_LPCOMP_AIN,
+  .lpcomp_refsel = PWRMGT_LPCOMP_REFSEL,
+  .voltage_bootlock = PWRMGT_VOLTAGE_BOOTLOCK
+};
+
+void R1NeoBoard::initiateShutdown(uint8_t reason) {
+  // Disable LoRa module power before shutdown
+  digitalWrite(SX126X_POWER_EN, LOW);
+
+  if (reason == SHUTDOWN_REASON_LOW_VOLTAGE ||
+      reason == SHUTDOWN_REASON_BOOT_PROTECT) {
+    configureVoltageWake(power_config.lpcomp_ain_channel, power_config.lpcomp_refsel);
+  }
+
+  enterSystemOff(reason);
+}
+#endif // NRF52_POWER_MANAGEMENT
+
+void R1NeoBoard::begin() {
+  // R1 Neo peculiarity: tell DCDC converter to stay powered.
+  // Must be done as soon as practical during boot.
+
+  pinMode(PIN_DCDC_EN_MCU_HOLD, OUTPUT);
+  digitalWrite(PIN_DCDC_EN_MCU_HOLD, HIGH);
+
+  // R1 Neo peculiarity: Tell I/O Controller device is on
+  // Enables passthrough of buttons and LEDs
+
+  pinMode(PIN_SOFT_SHUTDOWN, OUTPUT);
+  digitalWrite(PIN_SOFT_SHUTDOWN, HIGH);
+
+  NRF52BoardDCDC::begin();
+
+  // button is active high and passed through from I/O controller
+  pinMode(PIN_USER_BTN, INPUT);
+
+  pinMode(PIN_BUZZER, OUTPUT);
+  digitalWrite(PIN_BUZZER, LOW);
+
+  // battery pins
+  pinMode(PIN_BAT_CHG, INPUT);
+  pinMode(PIN_VBAT_READ, INPUT);
+
+  Wire.setPins(PIN_WIRE_SDA, PIN_WIRE_SCL);
+
+  Wire.begin();
+
+  pinMode(SX126X_POWER_EN, OUTPUT);
+#ifdef NRF52_POWER_MANAGEMENT
+  // Boot voltage protection check (may not return if voltage too low)
+  // We need to call this after we configure SX126X_POWER_EN as output but before we pull high
+  checkBootVoltage(&power_config);
+#endif
+  digitalWrite(SX126X_POWER_EN, HIGH);
+  delay(10);   // give sx1262 some time to power up
+}