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Aspeed Watchdog Timer
Required properties:
- compatible: must be one of:
- "aspeed,ast2400-wdt"
- "aspeed,ast2500-wdt"
- "aspeed,ast2600-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 specified 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.
Optional properties for AST2500- and AST2600-compatible watchdogs:
- aspeed,reset-mask: A bitmask indicating which peripherals will be reset if
the watchdog timer expires. On AST2500 this should be a
single word defined using the AST2500_WDT_RESET_* macros;
on AST2600 this should be a two-word array with the first
word defined using the AST2600_WDT_RESET1_* macros and the
second word defined using the AST2600_WDT_RESET2_* macros.
Examples:
wdt1: watchdog@1e785000 {
compatible = "aspeed,ast2400-wdt";
reg = <0x1e785000 0x1c>;
aspeed,reset-type = "system";
aspeed,external-signal;
};
#include <dt-bindings/watchdog/aspeed-wdt.h>
wdt2: watchdog@1e785040 {
compatible = "aspeed,ast2600-wdt";
reg = <0x1e785040 0x40>;
aspeed,reset-mask = <AST2600_WDT_RESET1_DEFAULT
(AST2600_WDT_RESET2_DEFAULT & ~AST2600_WDT_RESET2_LPC)>;
};
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