[3.16.y-ckt stable] Patch "iio: pressure: mpl115: fix temperature offset sign" has been added to the 3.16.y-ckt tree

Luis Henriques luis.henriques at canonical.com
Thu Feb 25 18:33:03 UTC 2016


This is a note to let you know that I have just added a patch titled

    iio: pressure: mpl115: fix temperature offset sign

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt25.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

---8<------------------------------------------------------------

>From f1da7f504ca80e6e5fcbccf1585037ffe83babb1 Mon Sep 17 00:00:00 2001
From: Akinobu Mita <akinobu.mita at gmail.com>
Date: Thu, 21 Jan 2016 01:07:31 +0900
Subject: iio: pressure: mpl115: fix temperature offset sign

commit 431386e783a3a6c8b7707bee32d18c353b8688b2 upstream.

According to the datasheet, the resolusion of temperature sensor is
-5.35 counts/C. Temperature ADC is 472 counts at 25C.
(https://www.sparkfun.com/datasheets/Sensors/Pressure/MPL115A1.pdf
NOTE: This is older revision, but this information is removed from the
latest datasheet from nxp somehow)

Temp [C] = (Tadc - 472) / -5.35 + 25
         = (Tadc - 605.750000) * -0.186915888

So the correct offset is -605.750000.

Signed-off-by: Akinobu Mita <akinobu.mita at gmail.com>
Acked-by: Peter Meerwald-Stadler <pmeerw at pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23 at kernel.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/iio/pressure/mpl115.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/pressure/mpl115.c b/drivers/iio/pressure/mpl115.c
index f5ecd6e19f5d..a0d7deeac62f 100644
--- a/drivers/iio/pressure/mpl115.c
+++ b/drivers/iio/pressure/mpl115.c
@@ -117,7 +117,7 @@ static int mpl115_read_raw(struct iio_dev *indio_dev,
 		*val = ret >> 6;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
-		*val = 605;
+		*val = -605;
 		*val2 = 750000;
 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_SCALE:




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