Hi,
On Sat, Jan 11, 2020 at 12:21:45PM +0100, Guido Günther wrote:
> Hi,
> On Wed, Jan 08, 2020 at 04:58:52PM +0100, Tomas Novotny wrote:
> > Vishay has published a new version of "Designing the VCNL4200 Into an
> > Application" application note in October 2019. The new version specifies
> > that there is +-20% of part to part tolerance. Although the application
> > note is related to vcnl4200, according to support the vcnl4040's "ASIC
> > is quite similar to that one for the VCNL4200".
> >
> > So update the sampling rates (and comment), including the correct
> > sampling rate for proximity. Both sampling rates are lower. Users
> > relying on the blocking behaviour of reading will get proximity
> > measurements much earlier.
> >
> > Fixes: 5a441aade5b3 ("iio: light: vcnl4000 add support for the VCNL4040 proximity and light sensor")
> > Signed-off-by: Tomas Novotny <tomas@xxxxxxxxxx>
> > ---
> > drivers/iio/light/vcnl4000.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
> > index 98428bf430bd..e5b00a6611ac 100644
> > --- a/drivers/iio/light/vcnl4000.c
> > +++ b/drivers/iio/light/vcnl4000.c
> > @@ -174,9 +174,10 @@ static int vcnl4200_init(struct vcnl4000_data *data)
> > data->al_scale = 24000;
> > break;
> > case VCNL4040_PROD_ID:
> > - /* Integration time is 80ms, add 10ms. */
> > - data->vcnl4200_al.sampling_rate = ktime_set(0, 100000 * 1000);
> > - data->vcnl4200_ps.sampling_rate = ktime_set(0, 100000 * 1000);
> > + /* Default wait time is 80ms, add 20% tolerance. */
> > + data->vcnl4200_al.sampling_rate = ktime_set(0, 96000 * 1000);
> > + /* Default wait time is 5ms, add 20% tolerance. */
> > + data->vcnl4200_ps.sampling_rate = ktime_set(0, 6000 * 1000);
>
> I'm seeing the 80ms in VCNL4040 Application guide (Revision:
> 12-Nov-2019) but that one also says 6400us for the proximity so 8000
> might be more on the safe side which (which i just tested, it's still
> way better than the current 100000).
In fact i was looking at the wrong value so no changes required:
Reviewed-by: Guido Günther <agx@xxxxxxxxxxx>
Tested-by: Guido Günther <agx@xxxxxxxxxxx>
-- Guido
>
> with that fixed
>
> Reviewed-by: Guido Günther <agx@xxxxxxxxxxx>
>
> Cheers,
> -- Guido
>
> > data->al_scale = 120000;
> > break;
> > }
> > --
> > 2.16.4
> >
