The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b42aa97ed5f1169cfd37175ef388ea62ff2dcf43 Mon Sep 17 00:00:00 2001

From: Tomas Novotny tomas@novotny.cz Date: Tue, 18 Feb 2020 16:44:50 +0100 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

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 agx@sigxcpu.org Signed-off-by: Tomas Novotny tomas@novotny.cz Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com

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: