On Thu, Jul 13, 2023 at 09:39:18AM +0530, Viresh Kumar wrote:
> On 12-07-23, 19:48, Dmitry Baryshkov wrote:
> > On Wed, 12 Jul 2023 at 19:34, Manivannan Sadhasivam
> > <manivannan.sadhasivam@xxxxxxxxxx> wrote:
> > > On Wed, Jul 12, 2023 at 04:15:12PM +0300, Dmitry Baryshkov wrote:
> > > > On 12/07/2023 13:32, Manivannan Sadhasivam wrote:
>
> > > > > +static int ufshcd_opp_config_clks(struct device *dev, struct opp_table *opp_table,
> > > > > + struct dev_pm_opp *opp, void *data,
> > > > > + bool scaling_down)
> > > > > +{
> > > > > + struct ufs_hba *hba = dev_get_drvdata(dev);
> > > > > + struct list_head *head = &hba->clk_list_head;
> > > > > + struct ufs_clk_info *clki;
> > > > > + unsigned long freq;
> > > > > + u8 idx = 0;
> > > > > + int ret;
> > > > > +
> > > > > + list_for_each_entry(clki, head, list) {
> > > > > + if (!IS_ERR_OR_NULL(clki->clk)) {
> > > > > + freq = dev_pm_opp_get_freq_indexed(opp, idx++);
> > > > > +
> > > > > + /* Do not set rate for clocks having frequency as 0 */
> > > > > + if (!freq)
> > > > > + continue;
> > > >
> > > > Can we omit these clocks from the opp table? I don't think they serve any
> > > > purpose.
> > > >
> > >
> > > No, we cannot. OPP requires the clocks and opp-hz to be of same length.
>
> I am okay with having a patch for the OPP core to modify this
> behavior, as I told privately earlier.
>
> > > And we
> > > cannot omit those clocks as well since linux needs to gate control them.
> >
> > Hmm, I thought we push the list of "interesting" clocks through
> > config->clock_names.
>
> Yes, another way to solve this would be keep the interesting clocks in
> the beginning in "clock-names" field and let the platform pass only
> those to the OPP core.
>
> > >
> > > > Maybe it would even make sense to move this function to drivers/opp then, as
> > > > it will be generic enough.
> > > >
> > >
> > > There is already a generic function available in OPP core. But we cannot use it
> > > as we need to skip setting 0 freq and that's not applicable in OPP core as
> > > discussed with Viresh offline.
> >
> > Ack.
>
> I am okay with either of the solutions, it is for you guys to decide
> what works better for your platform.
>
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.
- Mani
> --
> viresh
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