From 179f5bb66c8573acefcea7da0ced3df121a11224 Mon Sep 17 00:00:00 2001 From: Tomas Novotny Date: Fri, 17 Apr 2020 15:55:54 +0800 Subject: [PATCH] iio: light: vcnl4000: update sampling periods for vcnl4200 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit b42aa97ed5f1169cfd37175ef388ea62ff2dcf43 ] 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 Signed-off-by: Sasha Levin Signed-off-by: Yang Yingliang --- 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 04fd0d4b6f19..d3d65ecb30a5 100644 --- a/drivers/iio/light/vcnl4000.c +++ b/drivers/iio/light/vcnl4000.c @@ -150,9 +150,10 @@ static int vcnl4200_init(struct vcnl4000_data *data) data->al_scale = 24000; data->vcnl4200_al.reg = VCNL4200_AL_DATA; data->vcnl4200_ps.reg = VCNL4200_PS_DATA; - /* 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->vcnl4200_al.last_measurement = ktime_set(0, 0); data->vcnl4200_ps.last_measurement = ktime_set(0, 0); mutex_init(&data->vcnl4200_al.lock); -- GitLab