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@xxxxxxxxxx>
> ---
> 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@xxxxxxxxxxx>
Cheers,
-- Guido
> --
> 2.16.4
>
