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From: Enric Balletbo i Serra <enric.balletbo@collabora.com>
To: Jonathan Cameron <jic23@kernel.org>,
	linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Gwendal Grignou <gwendal@chromium.org>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	Guenter Roeck <groeck@chromium.org>,
	Benson Leung <bleung@chromium.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
	kernel@collabora.com, Hartmut Knaack <knaack.h@gmx.de>
Subject: [PATCH] iio: cros_ec: Fix gyro scale calculation
Date: Wed, 20 Feb 2019 16:03:00 +0100	[thread overview]
Message-ID: <20190220150300.3302-1-enric.balletbo@collabora.com> (raw)

From: Gwendal Grignou <gwendal@chromium.org>

Calculation was copied from IIO_DEGREE_TO_RAD, but offset added to avoid
rounding error is wrong. It should be only half of the divider.

Fixes: c14dca07a31d ("iio: cros_ec_sensors: add ChromeOS EC Contiguous Sensors driver")
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

 drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
index 89cb0066a6e0..600942af9f9c 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
@@ -103,7 +103,7 @@ static int cros_ec_sensors_read(struct iio_dev *indio_dev,
 			 * Do not use IIO_DEGREE_TO_RAD to avoid precision
 			 * loss. Round to the nearest integer.
 			 */
-			*val = div_s64(val64 * 314159 + 9000000ULL, 1000);
+			*val = div_s64(val64 * 314159 + 500ULL, 1000);
 			*val2 = 18000 << (CROS_EC_SENSOR_BITS - 1);
 			ret = IIO_VAL_FRACTIONAL;
 			break;
-- 
2.20.1


             reply	other threads:[~2019-02-20 15:03 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-20 15:03 Enric Balletbo i Serra [this message]
2019-02-20 16:01 ` [PATCH] iio: cros_ec: Fix gyro scale calculation Jonathan Cameron
2019-02-22 10:24   ` Enric Balletbo i Serra
2019-03-03 16:47     ` Jonathan Cameron
2019-03-06 11:16       ` Enric Balletbo i Serra

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