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From: Christian Eggers <ceggers@arri.de>
To: Jonathan Cameron <jic23@kernel.org>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
	Hartmut Knaack <knaack.h@gmx.de>,
	Lars-Peter Clausen <lars@metafoo.de>,
	"Peter Meerwald-Stadler" <pmeerw@pmeerw.net>,
	<linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	Christian Eggers <ceggers@arri.de>
Subject: [PATCH] iio: light: as73211: Increase measurement timeout
Date: Wed, 9 Sep 2020 17:44:39 +0200	[thread overview]
Message-ID: <20200909154439.10308-1-ceggers@arri.de> (raw)

We found some sensors which are much slower (20% at room temperature)
than nominal. According to the data sheet, up to 27% is possible. Now I
add 33% to the nominal time out, hopefully this is enough.

Signed-off-by: Christian Eggers <ceggers@arri.de>
---
 drivers/iio/light/as73211.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/light/as73211.c b/drivers/iio/light/as73211.c
index 25e5c386d678..457bf7f4b1f4 100644
--- a/drivers/iio/light/as73211.c
+++ b/drivers/iio/light/as73211.c
@@ -259,10 +259,9 @@ static int as73211_req_data(struct as73211_data *data)
 	data->osr &= ~AS73211_OSR_SS;
 
 	/*
-	 * Add some extra margin for the timeout. sensor timing is not as precise
-	 * as our one ...
+	 * Add 33% extra margin for the timeout. fclk,min = fclk,typ - 27%.
 	 */
-	time_us += time_us / 8;
+	time_us += time_us / 3;
 	if (data->client->irq) {
 		ret = wait_for_completion_timeout(&data->completion, usecs_to_jiffies(time_us));
 		if (!ret) {
-- 
Christian Eggers
Embedded software developer

Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918
Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477
Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler


             reply	other threads:[~2020-09-09 15:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-09 15:44 Christian Eggers [this message]
2020-09-09 16:58 ` [PATCH] iio: light: as73211: Increase measurement timeout Andy Shevchenko
2020-09-09 18:04   ` Christian Eggers
2020-09-13  9:39     ` Jonathan Cameron

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