xref: /freebsd/sys/contrib/device-tree/Bindings/watchdog/atmel-wdt.txt (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)

* Atmel Watchdog Timers

** at91sam9-wdt

Required properties:
- compatible: must be "atmel,at91sam9260-wdt".
- reg: physical base address of the controller and length of memory mapped
  region.
- clocks: phandle to input clock.

Optional properties:
- timeout-sec: contains the watchdog timeout in seconds.
- interrupts : Should contain WDT interrupt.
- atmel,max-heartbeat-sec : Should contain the maximum heartbeat value in
	seconds. This value should be less or equal to 16. It is used to
	compute the WDV field.
- atmel,min-heartbeat-sec : Should contain the minimum heartbeat value in
	seconds. This value must be smaller than the max-heartbeat-sec value.
	It is used to compute the WDD field.
- atmel,watchdog-type : Should be "hardware" or "software". Hardware watchdog
	use the at91 watchdog reset. Software watchdog use the watchdog
	interrupt to trigger a software reset.
- atmel,reset-type : Should be "proc" or "all".
	"all" : assert peripherals and processor reset signals
	"proc" : assert the processor reset signal
	This is valid only when using "hardware" watchdog.
- atmel,disable : Should be present if you want to disable the watchdog.
- atmel,idle-halt : Should be present if you want to stop the watchdog when
	entering idle state.
	CAUTION: This property should be used with care, it actually makes the
	watchdog not counting when the CPU is in idle state, therefore the
	watchdog reset time depends on mean CPU usage and will not reset at all
	if the CPU stop working while it is in idle state, which is probably
	not what you want.
- atmel,dbg-halt : Should be present if you want to stop the watchdog when
	entering debug state.

Example:
	watchdog@fffffd40 {
		compatible = "atmel,at91sam9260-wdt";
		reg = <0xfffffd40 0x10>;
		interrupts = <1 IRQ_TYPE_LEVEL_HIGH 7>;
		clocks = <&clk32k>;
		timeout-sec = <15>;
		atmel,watchdog-type = "hardware";
		atmel,reset-type = "all";
		atmel,dbg-halt;
		atmel,idle-halt;
		atmel,max-heartbeat-sec = <16>;
		atmel,min-heartbeat-sec = <0>;
	};