Re: [PATCH v7 14/33] crypto: rockchip: handle reset also in PM

John Keeping
2022-06-21T13:38:55Z

On Tue, Jun 21, 2022 at 10:05:54AM +0200, LABBE Corentin wrote:
> Le Mon, Jun 20, 2022 at 12:04:24PM +0100, John Keeping a écrit :
> > On Sun, May 08, 2022 at 06:59:38PM +0000, Corentin Labbe wrote:
> > > reset could be handled by PM functions.
> >
> > Is there any further rationale for this?
> >
> > After this change there is no longer a guaranteed reset pulse on probe
> > since the reset control may already be de-asserted. This is normally
> > the most important case for a reset as it's the only time when the state
> > of the hardware is unknown.
> >
> > The original use of devm_add_action_or_reset() seems a bit weird already
> > since there doesn't seem to be any need to assert reset when the driver
> > is unloaded.
> >
>
> I am not an hw engineer, so my knowledge on reset is low.
> So why not having a reset pulse on probe is a problem ?

The point of the reset is to bring the hardware back to a known state.
Since we don't know what state the hardware will be in following the
bootloader or previous OS, I think the reset in probe is the only place
that it is important.

If this patch isn't fixing anything, I suggest just dropping it.