RE: [PATCH] watchdog: da9062: add power management ops

[Adam Thomson <Adam.Thomson.Opensource@diasemi.com>]

On 02 December 2019 15:06, Marco Felsch wrote:

> On 19-12-02 14:44, Adam Thomson wrote:
> > On 02 December 2019 13:38, Adam Thomson wrote:
> >
> > > On 12/2/19 5:27 AM, Adam Thomson wrote:
> > > > Hi Marco,
> > > >
> > > >>> Hmmm. Wouldn't that then be a board specific fix rather than this
> change?
> > > >>> Am concerned relying on software to reenable the watchdog on resume
> > > could
> > > >> allow
> > > >>> for a hang scenario potentially if that code never gets to execute. Other
> > > >>> systems shouldn't need this fix, assuming they don't have issues at the
> HW
> > > >>> level, so this this seems like it could be making those systems less robust.
> If
> > > >>> we are to do this at the driver level, maybe this should be an option
> through
> > > DT
> > > >>> to help faulty systems, but I'm thinking this shouldn't be default
> behaviour.
> > > >>
> > > >> I don't think that we should rely on the OTP values. Those values are
> > > >> set by Dialog, the SoM manufacturers or by the customer itself and the
> > > >> time shows that this is error prone too. At least if the customer or the
> > > >> SoM manufacturer don't ask the Dialog Support..
> > > >>
> > > >> You're right with the (re-)enabling but there are other drivers using
> > > >> such an approach.. IMHO it is safer to go this way rather than trust
> > > >> the OTP and the PCB layout. I would rather add a dt-compatible to tell
> > > >> the driver to do nothing during suspend/resume e.g.:
> > > >>
> > > >>      - dlg,use-hw-pm
> > > >>
> > > >> or something. Because the user needs to validate the PCB and the OTP
> > > >> values.
> > > >
> > > > The thing is the DT FW is supposed to be fairly static so I would rather not
> > > > enforce this change on users if they adopt a kernel version with this update
> in.
> > > > I also still think it's safer if the HW does this for us. I would have hoped for
> > > > most designs this would be caught in early bring up where it can be rectified
> > > > with minimal impact, although I'm guessing that's not the case in your
> scenario.
> > > >
> > >
> > > dla,use-sw-pm ?
> > > dla,hw-pm-broken ?
> >
> > Yes, I'd probably opt for 'dlg,use-sw-pm' or maybe 'dlg,manual-pm' to cover it.
> 
> Okay, so we are all agree with the dlg,use-sw-pm?

Yep, that's ok for me

> 
> Regards,
>   Marco
> 
> >
> > >
> > > Guenter
> 
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