iio: pressure: mpl115: fix temperature offset sign
authorAkinobu Mita <akinobu.mita@gmail.com>
Wed, 20 Jan 2016 16:07:31 +0000 (01:07 +0900)
committerJonathan Cameron <jic23@kernel.org>
Sat, 30 Jan 2016 16:07:32 +0000 (16:07 +0000)
commit431386e783a3a6c8b7707bee32d18c353b8688b2
treef1443db133e55388affeb9f50754e9c74b77af3c
parentd81dac3c1c5295c61b15293074ac2bd3254e1875
iio: pressure: mpl115: fix temperature offset sign

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@gmail.com>
Acked-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
drivers/iio/pressure/mpl115.c