xref: /freebsd/sys/contrib/device-tree/Bindings/watchdog/atmel-wdt.txt (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
1* Atmel Watchdog Timers
2
3** at91sam9-wdt
4
5Required properties:
6- compatible: must be "atmel,at91sam9260-wdt".
7- reg: physical base address of the controller and length of memory mapped
8  region.
9- clocks: phandle to input clock.
10
11Optional properties:
12- timeout-sec: contains the watchdog timeout in seconds.
13- interrupts : Should contain WDT interrupt.
14- atmel,max-heartbeat-sec : Should contain the maximum heartbeat value in
15	seconds. This value should be less or equal to 16. It is used to
16	compute the WDV field.
17- atmel,min-heartbeat-sec : Should contain the minimum heartbeat value in
18	seconds. This value must be smaller than the max-heartbeat-sec value.
19	It is used to compute the WDD field.
20- atmel,watchdog-type : Should be "hardware" or "software". Hardware watchdog
21	use the at91 watchdog reset. Software watchdog use the watchdog
22	interrupt to trigger a software reset.
23- atmel,reset-type : Should be "proc" or "all".
24	"all" : assert peripherals and processor reset signals
25	"proc" : assert the processor reset signal
26	This is valid only when using "hardware" watchdog.
27- atmel,disable : Should be present if you want to disable the watchdog.
28- atmel,idle-halt : Should be present if you want to stop the watchdog when
29	entering idle state.
30	CAUTION: This property should be used with care, it actually makes the
31	watchdog not counting when the CPU is in idle state, therefore the
32	watchdog reset time depends on mean CPU usage and will not reset at all
33	if the CPU stop working while it is in idle state, which is probably
34	not what you want.
35- atmel,dbg-halt : Should be present if you want to stop the watchdog when
36	entering debug state.
37
38Example:
39	watchdog@fffffd40 {
40		compatible = "atmel,at91sam9260-wdt";
41		reg = <0xfffffd40 0x10>;
42		interrupts = <1 IRQ_TYPE_LEVEL_HIGH 7>;
43		clocks = <&clk32k>;
44		timeout-sec = <15>;
45		atmel,watchdog-type = "hardware";
46		atmel,reset-type = "all";
47		atmel,dbg-halt;
48		atmel,idle-halt;
49		atmel,max-heartbeat-sec = <16>;
50		atmel,min-heartbeat-sec = <0>;
51	};
52