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?
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
> >
