Hi Bean,
On Wed, 2020-03-18 at 22:10 +0000, Bean Huo (beanhuo) wrote:
> Hi, Stanley
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index
> > 314e808b0d4e..a42a84164dec 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -597,6 +597,18 @@ static void ufshcd_print_pwr_info(struct ufs_hba *hba)
> > hba->pwr_info.hs_rate);
> > }
> >
> > +void ufshcd_delay_us(unsigned long us, unsigned long tolerance) {
> > + if (!us)
> > + return;
> > +
> > + if (us < 10)
> > + udelay(us);
> > + else
> > + usleep_range(us, us + tolerance);
> > +}
> > +EXPORT_SYMBOL_GPL(ufshcd_delay_us);
> > +
> In this way, the callers of ufshcd_delay_us(), can directly call udelay() or usleep_range(), what is exist meaning of ufshcd_delay_us()?
Sure, the callers always can directly call udelay() or usleep_range().
The customizable delay (either by hosts or devices) value in UFS driver
is becoming more and more, like "reference clock gating delay" and
introduced "hce_enable_delay". The customized delay time could be 0, <
10 us, or >= 10 us in real cases. Hence this function can help driver
simplify the driver and user's decision of "just passed without any
delay" or "choosing a suitable delay function according to the delay
time".
Thanks,
Stanley Chu
