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SubjectRe: [PATCH 1/2] drivers/watchdog: Document new aspeed optional dev tree properties.
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On 6/26/17 9:59 PM, Joel Stanley wrote:
> On Wed, Jun 14, 2017 at 6:08 AM, Christopher Bostic
> <cbostic@linux.vnet.ibm.com> wrote:
>> Describe new optional property 'external-signal'. When present in the
>> system device tree an exernal signal is generated on watchdog timeout.
>>
>> Describe new optional property 'no-system-reset'. When present in the
>> system device tree no system reset is to occur on watchdog timeout.
>> System reset in this case is managed by one of the other watchogs
>> available.
>>
>> Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
>> ---
>> Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> index c5e74d7..4099ea5 100644
>> --- a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> +++ b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> @@ -8,9 +8,20 @@ Required properties:
>> - reg: physical base address of the controller and length of memory mapped
>> region
>>
>> +Optional properties:
>> + - external-signal: If the property is present then an external signal is to
>> + be generated on watchdog timeout. If absent, external signal is not
>> + generated.
>> +
>> + - no-system-reset: If the property is present then system will not be reset
>> + on watchdog timeout. In this case one of the other watchdogs will handle
>> + reset. If absent then the watchdog resets the system on timeout.
> I'm not sure that this describes the hardware. The datasheet says:
>
> Whenever timeout ocurs, WDT can program to generate 6 types of signals:
>
> * ARM reset signal: to reset ARM CPU only
> * SOC reset signal: to reset SOC part function
> * System reset signal: to reset full chip
> * Interrupt signal: to interrupt CPU
> * Eternal signal: to external reset counter (only WDT1 and WDT2)
> * Alternate boot signal: to boot from alternate block
>
> I think your bindings should describe these modes where possible.

I'll add the modes you describe.

Thanks,
Chris
>
> Cheers,
>
> Joel
>
>
>> +
>> Example:
>>
>> wdt1: watchdog@1e785000 {
>> compatible = "aspeed,ast2400-wdt";
>> reg = <0x1e785000 0x1c>;
>> + external-signal;
>> + no-system-reset;
>> };
>> --
>> 1.8.2.2
>>

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