From b42aa97ed5f1169cfd37175ef388ea62ff2dcf43 Mon Sep 17 00:00:00 2001 From: Tomas Novotny Date: Tue, 18 Feb 2020 16:44:50 +0100 Subject: iio: light: vcnl4000: update sampling periods for vcnl4200 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 periods. As the reading is blocking, current users may notice slightly longer response time. Fixes: be38866fbb97 ("iio: vcnl4000: add support for VCNL4200") Reviewed-by: Guido Günther Signed-off-by: Tomas Novotny Cc: Signed-off-by: Jonathan Cameron --- drivers/iio/light/vcnl4000.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/iio/light/vcnl4000.c') 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: -- cgit v1.2.3 From 2ca5a8792d617b4035aacd0a8be527f667fbf912 Mon Sep 17 00:00:00 2001 From: Tomas Novotny Date: Tue, 18 Feb 2020 16:44:51 +0100 Subject: iio: light: vcnl4000: update sampling periods for vcnl4040 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 periods (and comment), including the correct sampling period for proximity. Both sampling periods 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") Reviewed-by: Guido Günther Tested-by: Guido Günther Signed-off-by: Tomas Novotny Cc: Signed-off-by: Jonathan Cameron --- drivers/iio/light/vcnl4000.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/iio/light/vcnl4000.c') 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); data->al_scale = 120000; break; } -- cgit v1.2.3