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- Aspeed Watchdog Timer
- Required properties:
- - compatible: must be one of:
- - "aspeed,ast2400-wdt"
- - "aspeed,ast2500-wdt"
- - reg: physical base address of the controller and length of memory mapped
- region
- Optional properties:
- - aspeed,reset-type = "cpu|soc|system|none"
- Reset behavior - Whenever a timeout occurs the watchdog can be programmed
- to generate one of three different, mutually exclusive, types of resets.
- Type "none" can be specified to indicate that no resets are to be done.
- This is useful in situations where another watchdog engine on chip is
- to perform the reset.
- If 'aspeed,reset-type=' is not specfied the default is to enable system
- reset.
- Reset types:
- - cpu: Reset CPU on watchdog timeout
- - soc: Reset 'System on Chip' on watchdog timeout
- - system: Reset system on watchdog timeout
- - none: No reset is performed on timeout. Assumes another watchdog
- engine is responsible for this.
- - aspeed,alt-boot: If property is present then boot from alternate block.
- - aspeed,external-signal: If property is present then signal is sent to
- external reset counter (only WDT1 and WDT2). If not
- specified no external signal is sent.
- - aspeed,ext-pulse-duration: External signal pulse duration in microseconds
- Optional properties for AST2500-compatible watchdogs:
- - aspeed,ext-push-pull: If aspeed,external-signal is present, set the pin's
- drive type to push-pull. The default is open-drain.
- - aspeed,ext-active-high: If aspeed,external-signal is present and and the pin
- is configured as push-pull, then set the pulse
- polarity to active-high. The default is active-low.
- Example:
- wdt1: watchdog@1e785000 {
- compatible = "aspeed,ast2400-wdt";
- reg = <0x1e785000 0x1c>;
- aspeed,reset-type = "system";
- aspeed,external-signal;
- };
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