/*
 * Copyright (C) 2019 Stuart Longland <me@vk4msl.id.au>
 *
 * Based on PB-I2C2-RTC-DS1307.dts:
 * 
 * Copyright (C) 2018 Tim Small <tim@seoss.co.uk>
 *
 * Based on PB-I2C2-RTC-PCF8523.dts:
 * 
 * Copyright (C) 2018 Robert Nelson <robertcnelson@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This overlay is for a Microchip MCP7940X RTC connected via the
 * BeagleBone's second I2C bus.
 * https://www.microchip.com/wwwproducts/en/MCP79400
 *
 * Brisbane WICEN are using this RTC for their RFID field terminals to keep
 * time whilst the PocketBeagle is powered down to prevent lengthy NTP time
 * synchronisation sessions over AX.25, but may be useful for others.
 */

/dts-v1/;
/plugin/;

#include <dt-bindings/board/am335x-bbw-bbb-base.h>
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/pinctrl/am33xx.h>

/ {
	/*
	 * Helper to show loaded overlays under: /proc/device-tree/chosen/overlays/
	 */
	fragment@0 {
		target-path="/";
		__overlay__ {

			chosen {
				overlays {
					BB-I2C2-RTC-MCP7940X = __TIMESTAMP__;
				};
			};
		};
	};

	fragment@1 {
		target-path="/";
		__overlay__ {
			aliases {
				rtc0 = &extrtc;
				/* The OMAP RTC implementation in the BBB is
				 * buggy, so that it cannot be used as a
				 * battery-backed RTS, so that it loses its
				 * contents when power is removed from the
				 * Beaglebone...
				 *
				 * We move the omap built-in RTC to rtc1, so
				 * that userspace defaults to using the DS1307.
				 *
				 * The omap RTC must remain enabled because it
				 * is also used during the reboot process on the
				 * BBB.
				 */
				rtc1 = "/ocp/rtc@44e3e000";
			};
		};
	};

	fragment@2 {
		target = <&i2c2>;
		__overlay__ {
			status = "okay";

			#address-cells = <1>;
			#size-cells = <0>;

			extrtc: ds1307@68 {
				compatible = "microchip,mcp7940x";
				reg = <0x6f>;
			};
		};
	};
};