1 Aspeed Watchdog Timer
2
3 Required properties:
4 - compatible: must be one of:
5 - "aspeed,ast2400-wdt"
6 - "aspeed,ast2500-wdt"
7 - "aspeed,ast2600-wdt"
8
9 - reg: physical base address of the controller and length of memory mapped
10 region
11
12 Optional properties:
13
14 - aspeed,reset-type = "cpu|soc|system|none"
15
16 Reset behavior - Whenever a timeout occurs the watchdog can be programmed
17 to generate one of three different, mutually exclusive, types of resets.
18
19 Type "none" can be specified to indicate that no resets are to be done.
20 This is useful in situations where another watchdog engine on chip is
21 to perform the reset.
22
23 If 'aspeed,reset-type=' is not specified the default is to enable system
24 reset.
25
26 Reset types:
27
28 - cpu: Reset CPU on watchdog timeout
29
30 - soc: Reset 'System on Chip' on watchdog timeout
31
32 - system: Reset system on watchdog timeout
33
34 - none: No reset is performed on timeout. Assumes another watchdog
35 engine is responsible for this.
36
37 - aspeed,alt-boot: If property is present then boot from alternate block.
38 - aspeed,external-signal: If property is present then signal is sent to
39 external reset counter (only WDT1 and WDT2). If not
40 specified no external signal is sent.
41 - aspeed,ext-pulse-duration: External signal pulse duration in microseconds
42
43 Optional properties for AST2500-compatible watchdogs:
44 - aspeed,ext-push-pull: If aspeed,external-signal is present, set the pin's
45 drive type to push-pull. The default is open-drain.
46 - aspeed,ext-active-high: If aspeed,external-signal is present and and the pin
47 is configured as push-pull, then set the pulse
48 polarity to active-high. The default is active-low.
49
50 Example:
51
52 wdt1: watchdog@1e785000 {
53 compatible = "aspeed,ast2400-wdt";
54 reg = <0x1e785000 0x1c>;
55 aspeed,reset-type = "system";
56 aspeed,external-signal;
57 };
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