From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f67.google.com ([209.85.220.67]:35217 "EHLO mail-pa0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933838AbcATQHp (ORCPT ); Wed, 20 Jan 2016 11:07:45 -0500 Received: by mail-pa0-f67.google.com with SMTP id gi1so556977pac.2 for ; Wed, 20 Jan 2016 08:07:45 -0800 (PST) From: Akinobu Mita To: linux-iio@vger.kernel.org Cc: Akinobu Mita , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald Subject: [PATCH] iio: pressure: mpl115: fix temperature offset sign Date: Thu, 21 Jan 2016 01:07:31 +0900 Message-Id: <1453306051-8817-1-git-send-email-akinobu.mita@gmail.com> Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org 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 Cc: Jonathan Cameron Cc: Hartmut Knaack Cc: Lars-Peter Clausen Cc: Peter Meerwald Cc: linux-iio@vger.kernel.org --- 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 138344c..73f2f0c 100644 --- a/drivers/iio/pressure/mpl115.c +++ b/drivers/iio/pressure/mpl115.c @@ -118,7 +118,7 @@ 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: -- 2.5.0