Re: [PATCH 1/2] drivers/watchdog: Document new aspeed optional dev tree properties.

[Christopher Bostic]

On 6/26/17 9:59 PM, Joel Stanley wrote:
> On Wed, Jun 14, 2017 at 6:08 AM, Christopher Bostic
> <cbostic@xxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxx>
> > ---
> >   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