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 <CAJCx=gmi6=uXbydpE2gY2x-XijtAd=bfufoJ+gbO1KU1n++g3Q@mail.gmail.com> <20190422114821.5955d4fa@archlinux>
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From:   Matt Ranostay <matt.ranostay@konsulko.com>
Date:   Wed, 24 Apr 2019 17:23:26 +0800
Message-ID: <CAJCx=g=8WEAVxdhOQni1gd2D-mTbuc8kTa6nQhF3nQ9JfGDJKg@mail.gmail.com>
Subject: Re: [PATCH] drivers: iio: proximity: This patch fix the following
 checkpatch warning.
To:     Jonathan Cameron <jic23@kernel.org>
Cc:     Mohan Kumar <mohankumar718@gmail.com>,
        Andreas Klinger <ak@it-klinger.de>,
        Hartmut Knaack <knaack.h@gmx.de>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
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On Mon, Apr 22, 2019 at 6:48 PM Jonathan Cameron <jic23@kernel.org> wrote:
>
> On Thu, 18 Apr 2019 16:23:51 -0700
> Matt Ranostay <matt.ranostay@konsulko.com> wrote:
>
> > See comments inline
> >
> > On Wed, Apr 17, 2019 at 11:15 AM Mohan Kumar <mohankumar718@gmail.com> wrote:
> > >
> > > As per Documentation/timers/timers-howto.txt Msleep < 20ms can sleep for
> > > up to 20ms. so use usleep_range.
> > >
> > > Signed-off-by: Mohan Kumar <mohankumar718@gmail.com>
> > > ---
> > >  drivers/iio/proximity/mb1232.c | 2 +-
> > >  drivers/iio/proximity/srf08.c  | 4 ++--
> > >  2 files changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/iio/proximity/mb1232.c b/drivers/iio/proximity/mb1232.c
> > > index 166b3e6..74f7eae 100644
> > > --- a/drivers/iio/proximity/mb1232.c
> > > +++ b/drivers/iio/proximity/mb1232.c
> > > @@ -81,7 +81,7 @@ static s16 mb1232_read_distance(struct mb1232_data *data)
> > >                 }
> > >         } else {
> > >                 /* use simple sleep if announce irq is not connected */
> > > -               msleep(15);
> > > +               usleep_range(15000, 20000);
> >
> > This is actually less than ideal.. because usleep_range uses the
> > hrtimers which forces an interrupt.
> >
> > Unless you actually need to read between 15ms and 20ms it is best just
> > to leave the msleep() as it is, and let it take a bit longer
> > if required.
> Good response.  Perhaps Mohan could follow up with a patch to add
> a comment to this effect to save anyone else trying to 'fix' this
> issue in future?

Change of the warning message in the checkpatch.pl script you mean?

- Matt

>
> Thanks,
>
> Jonathan
> >
> > - Matt
> >
> > >         }
> > >
> > >         ret = i2c_master_recv(client, (char *)&buf, sizeof(buf));
> > > diff --git a/drivers/iio/proximity/srf08.c b/drivers/iio/proximity/srf08.c
> > > index f2bf783..605a582 100644
> > > --- a/drivers/iio/proximity/srf08.c
> > > +++ b/drivers/iio/proximity/srf08.c
> > > @@ -150,7 +150,7 @@ static int srf08_read_ranging(struct srf08_data *data)
> > >          * polling for not more than 20 ms should be enough
> > >          */
> > >         waittime = 1 + data->range_mm / 172;
> > > -       msleep(waittime);
> > > +       usleep_range(waittime * 1000, (waittime * 1000) + 2000);
> > >         for (i = 0; i < 4; i++) {
> > >                 ret = i2c_smbus_read_byte_data(data->client,
> > >                                                 SRF08_READ_SW_REVISION);
> > > @@ -158,7 +158,7 @@ static int srf08_read_ranging(struct srf08_data *data)
> > >                 /* check if a valid version number is read */
> > >                 if (ret < 255 && ret > 0)
> > >                         break;
> > > -               msleep(5);
> > > +               usleep_range(5000, 15000);
> > >         }
> > >
> > >         if (ret >= 255 || ret <= 0) {
> > > --
> > > 2.7.4
> > >
>