On Wed, 24 Apr 2019 17:23:26 +0800
Matt Ranostay <matt.ranostay@xxxxxxxxxxxx> wrote:
> On Mon, Apr 22, 2019 at 6:48 PM Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> >
> > On Thu, 18 Apr 2019 16:23:51 -0700
> > Matt Ranostay <matt.ranostay@xxxxxxxxxxxx> wrote:
> >
> > > See comments inline
> > >
> > > On Wed, Apr 17, 2019 at 11:15 AM Mohan Kumar <mohankumar718@xxxxxxxxx> 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@xxxxxxxxx>
> > > > ---
> > > > 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?
No. That's basically telling people to 'think about it'. I meant a comment
in the source for this driver to say 'We don't care here because...'.
That way anyone preparing a patch for this in future will see the comment
and not bother.
Jonathan
>
> - 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
> > > >
> >
