Re: [PATCH 11/14] scsi: ufs: host: Add support for parsing OPP

From: Viresh Kumar
Date: Thu Jul 13 2023 - 01:43:11 EST


Okay, sorry about missing one point first. I thought we are adding the
clk config callback (which neglects 0 frequencies) to a Qcom only
driver and so was okay-ish with that. But now that I realize that this
is a generic driver instead (my mistake here), I wonder if it is the
right thing to do anymore.

On 13-07-23, 10:58, Manivannan Sadhasivam wrote:
> On Thu, Jul 13, 2023 at 10:42:35AM +0530, Viresh Kumar wrote:
> > On 13-07-23, 10:35, Manivannan Sadhasivam wrote:
> > > We can settle with this custom callback for now. If there are drivers in the
> > > future trying to do the same (skipping 0 freq) then we can generalize.
> >
> > Just for completeness, there isn't much to generalize here apart from
> > changing the DT order of clocks. Isn't it ?
> >
>
> Even with changing the order, driver has to know the "interesting" clocks
> beforehand. But that varies between platforms (this is a generic driver for
> ufshc platforms).
>
> And I do not know if clocks have any dependency between them, atleast not in
> Qcom platforms. But not sure about others.

Maybe this requires some sort of callback, per-platform, which gets
you these details or the struct dev_pm_opp_config itself (so platforms
can choose the callback too, in case order is important).

> > The change require for the OPP core makes sense, I will probably just
> > push it anyway.

I tried to look at this code and I think it is doing the right thing
currently, i.e. it matches clk-count with the number of frequencies in
opp-hz, which should turn out to be the same in your case. So nothing
to change here I guess.

--
viresh