| Message ID | 20200108155852.32702-2-tomas@novotny.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: light: vcnl4000: update sampling rates | expand |
Hi, On Wed, Jan 08, 2020 at 04:58:51PM +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. This explains the drift > seen during experiments. The proximity pulse width is also changed from > 32us to 30us. According to the support, the tolerance also applies to > ambient light. > > So update the sampling rates. As the reading is blocking, current users > may notice slightly longer response time. > > Fixes: be38866fbb97 ("iio: vcnl4000: add support for VCNL4200") > Signed-off-by: Tomas Novotny <tomas@novotny.cz> > --- > drivers/iio/light/vcnl4000.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c > index b0e241aaefb4..98428bf430bd 100644 > --- a/drivers/iio/light/vcnl4000.c > +++ b/drivers/iio/light/vcnl4000.c > @@ -167,10 +167,10 @@ static int vcnl4200_init(struct vcnl4000_data *data) > data->vcnl4200_ps.reg = VCNL4200_PS_DATA; > switch (id) { > case VCNL4200_PROD_ID: > - /* Integration time is 50ms, but the experiments */ > - /* show 54ms in total. */ > - data->vcnl4200_al.sampling_rate = ktime_set(0, 54000 * 1000); > - data->vcnl4200_ps.sampling_rate = ktime_set(0, 4200 * 1000); > + /* Default wait time is 50ms, add 20% tolerance. */ > + data->vcnl4200_al.sampling_rate = ktime_set(0, 60000 * 1000); > + /* Default wait time is 4.8ms, add 20% tolerance. */ > + data->vcnl4200_ps.sampling_rate = ktime_set(0, 5760 * 1000); > data->al_scale = 24000; > break; > case VCNL4040_PROD_ID: Reviewed-by: Guido Günther <agx@sigxcpu.org> Cheers, -- Guido > -- > 2.16.4 >
diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c index b0e241aaefb4..98428bf430bd 100644 --- a/drivers/iio/light/vcnl4000.c +++ b/drivers/iio/light/vcnl4000.c @@ -167,10 +167,10 @@ static int vcnl4200_init(struct vcnl4000_data *data) data->vcnl4200_ps.reg = VCNL4200_PS_DATA; switch (id) { case VCNL4200_PROD_ID: - /* Integration time is 50ms, but the experiments */ - /* show 54ms in total. */ - data->vcnl4200_al.sampling_rate = ktime_set(0, 54000 * 1000); - data->vcnl4200_ps.sampling_rate = ktime_set(0, 4200 * 1000); + /* Default wait time is 50ms, add 20% tolerance. */ + data->vcnl4200_al.sampling_rate = ktime_set(0, 60000 * 1000); + /* Default wait time is 4.8ms, add 20% tolerance. */ + data->vcnl4200_ps.sampling_rate = ktime_set(0, 5760 * 1000); data->al_scale = 24000; break; case VCNL4040_PROD_ID:
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. This explains the drift seen during experiments. The proximity pulse width is also changed from 32us to 30us. According to the support, the tolerance also applies to ambient light. So update the sampling rates. As the reading is blocking, current users may notice slightly longer response time. Fixes: be38866fbb97 ("iio: vcnl4000: add support for VCNL4200") Signed-off-by: Tomas Novotny <tomas@novotny.cz> --- drivers/iio/light/vcnl4000.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)