1Aspeed Watchdog Timer 2 3Required 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 12Optional 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 43Optional 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 50Example: 51 52 wdt1: watchdog@1e785000 { 53 compatible = "aspeed,ast2400-wdt"; 54 reg = <0x1e785000 0x1c>; 55 aspeed,reset-type = "system"; 56 aspeed,external-signal; 57 }; 58