Re: [PATCH V2 1/2] opp: Allow dev_pm_opp_get_opp_table() to return -EPROBE_DEFER

Viresh Kumar
2020-10-19T05:00:15Z

On 16-10-20, 12:12, Sudeep Holla wrote:
> On Fri, Oct 16, 2020 at 07:00:21AM +0100, Sudeep Holla wrote:
> > On Fri, Oct 16, 2020 at 09:54:34AM +0530, Viresh Kumar wrote:
> > > On 15-10-20, 19:05, Sudeep Holla wrote:
> > > > OK, this breaks with SCMI which doesn't provide clocks but manage OPPs
> > > > directly. Before this change clk_get(dev..) was allowed to fail and
> > > > --EPROBE_DEFER was not an error.
> > >
> > > I think the change in itself is fine. We should be returning from
> > > there if we get EPROBE_DEFER. The question is rather why are you
> > > getting EPROBE_DEFER here ?
> > >
> >
> > Ah OK, I didn't spend too much time, saw -EPROBE_DEFER, just reverted
> > this patch and it worked. I need to check it in detail yet.
> >
>
> You confused me earlier. As I said there will be no clock provider
> registered for SCMI CPU/Dev DVFS.
> opp_table->clk = clk_get(dev, NULL);
> will always return -EPROBE_DEFER as there is no clock provider for dev.
> But this change now propagates that error to caller of dev_pm_opp_add
> which means we can't add opp to a device if there are no clock providers.
> This breaks for DVFS which don't operate separately with clocks and
> regulators.

The CPUs DT node shouldn't have a clock property in such a case and I
would expect an error instead of EPROBE_DEFER then. Isn't it ?

--
viresh