Re: [PATCH v1 1/2] scsi: ufs: add required delay after gating reference clock

[Can Guo]

On 2020-02-17 21:12, Stanley Chu wrote:
> Hi Can,
>
>
> > >  			} else if (!on && clki->enabled) {
> > >  				clk_disable_unprepare(clki->clk);
> > > +				wait_us = hba->dev_info.clk_gating_wait_us;
> > > +				if (ref_clk && wait_us)
> > > +					usleep_range(wait_us, wait_us + 10);
> >
> > Hi St,anley,
> >
> > If wait_us is 1us, it would be inappropriate to use usleep_range() 
> > here.
> > You have checks of the delay in patch #2, but why it is not needed 
> > here?
> >
> > Thanks,
> > Can Guo.
>
> You are right. I could make that delay checking as common function so 
> it
> can be used here as well to cover all possible values.
>
> Thanks for suggestion.
> Stanley

Hi Stanley,

One more thing, as in patch #2, you have already added delays in your
ufshcd_vops_setup_clocks(OFF, PRE_CHANGE) path, plus this delay here,
don't you delay for 2*bRefClkGatingWaitTime in ufshcd_setup_clocks()?
As the delay added in your vops also delays the actions of turning
off all the other clocks in ufshcd_setup_clocks(), you don't need the
delay here again, do you agree?

Thanks,
Can Guo.