On Sun, 2020-03-29 at 11:28 +0200, Julia Lawall wrote:
>
> On Sun, 29 Mar 2020, John B. Wyatt IV wrote:
>
> > Fix style issue with usleep_range being reported as preferred over
> > udelay.
> >
> > Issue reported by checkpatch.
> >
> > Please review.
> >
> > As written in Documentation/timers/timers-howto.rst udelay is the
> > generally preferred API. hrtimers, as noted in the docs, may be too
> > expensive for this short timer.
> >
> > Are the docs out of date, or, is this a checkpatch issue?
> >
> > Signed-off-by: John B. Wyatt IV
> > ---
> > drivers/staging/fbtft/fb_agm1264k-fl.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/staging/fbtft/fb_agm1264k-fl.c
> > b/drivers/staging/fbtft/fb_agm1264k-fl.c
> > index ec97ad27..019c8cce6bab 100644
> > --- a/drivers/staging/fbtft/fb_agm1264k-fl.c
> > +++ b/drivers/staging/fbtft/fb_agm1264k-fl.c
> > @@ -85,7 +85,7 @@ static void reset(struct fbtft_par *par)
> > dev_dbg(par->info->device, "%s()\n", __func__);
> >
> > gpiod_set_value(par->gpio.reset, 0);
> > - udelay(20);
> > + usleep_range(20, 20);
>
> usleep_range should have a range, eg usleep_range(50, 100);. But it
> is
> hard to know a priori what the range should be. So it is probably
> better
> to leave the code alone.
Understood.
With the question I wrote in the commit message:
"As written in Documentation/timers/timers-howto.rst udelay is the
generally preferred API. hrtimers, as noted in the docs, may be too
expensive for this short timer.
Are the docs out of date, or, is this a checkpatch issue?"
Is usleep_range too expensive for this operation?
Why does checkpatch favor usleep_range while the docs favor udelay?
>
> julia
>
> > gpiod_set_value(par->gpio.reset, 1);
> > mdelay(120);
> > }
> > --
> > 2.25.1
> >
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> > .
> >
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