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For the AST2500 and compatible watchdog controllers the external reset signal can be configured for push-pull or open-drain drive types, and in the case of push-pull driving, active low or high. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Acked-by: Rob Herring <robh@kernel.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
57 lines
1.8 KiB
Plaintext
57 lines
1.8 KiB
Plaintext
Aspeed Watchdog Timer
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Required properties:
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- compatible: must be one of:
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- "aspeed,ast2400-wdt"
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- "aspeed,ast2500-wdt"
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- reg: physical base address of the controller and length of memory mapped
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region
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Optional properties:
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- aspeed,reset-type = "cpu|soc|system|none"
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Reset behavior - Whenever a timeout occurs the watchdog can be programmed
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to generate one of three different, mutually exclusive, types of resets.
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Type "none" can be specified to indicate that no resets are to be done.
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This is useful in situations where another watchdog engine on chip is
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to perform the reset.
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If 'aspeed,reset-type=' is not specfied the default is to enable system
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reset.
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Reset types:
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- cpu: Reset CPU on watchdog timeout
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- soc: Reset 'System on Chip' on watchdog timeout
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- system: Reset system on watchdog timeout
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- none: No reset is performed on timeout. Assumes another watchdog
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engine is responsible for this.
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- aspeed,alt-boot: If property is present then boot from alternate block.
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- aspeed,external-signal: If property is present then signal is sent to
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external reset counter (only WDT1 and WDT2). If not
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specified no external signal is sent.
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- aspeed,ext-pulse-duration: External signal pulse duration in microseconds
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Optional properties for AST2500-compatible watchdogs:
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- aspeed,ext-push-pull: If aspeed,external-signal is present, set the pin's
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drive type to push-pull. The default is open-drain.
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- aspeed,ext-active-high: If aspeed,external-signal is present and and the pin
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is configured as push-pull, then set the pulse
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polarity to active-high. The default is active-low.
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Example:
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wdt1: watchdog@1e785000 {
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compatible = "aspeed,ast2400-wdt";
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reg = <0x1e785000 0x1c>;
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aspeed,reset-type = "system";
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aspeed,external-signal;
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};
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