Commit 71702e6e authored Nov 07, 2014 by Martin Fuzzey Committed by Jonathan Cameron Jul 12, 2014

iio: mma8452: Use correct acceleration units.



The userspace interface for acceleration sensors is documented as using
m/s^2 units [Documentation/ABI/testing/sysfs-bus-iio]

The fullscale raw value for the mma8452 (-2048) corresponds to -2G, -4G or -8G
depending on the seleted mode.

The scale table was converting to G rather than m/s^2.
Change the scaling table to match the documented interface.

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Cc: stable@vger.kernel.org

parent 78b33216

drivers/iio/accel/mma8452.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -111,8 +111,14 @@ static const int mma8452_samp_freq[8][2] = {
		{6, 250000}, {1, 560000}
		};

		/*
		* Hardware has fullscale of -2G, -4G, -8G corresponding to raw value -2048
		* The userspace interface uses m/s^2 and we declare micro units
		* So scale factor is given by:
		* g * N * 1000000 / 2048 for N = 2, 4, 8 and g=9.80665
		*/
		static const int mma8452_scales[3][2] = {
		{0, 977}, {0, 1953}, {0, 3906}
		{0, 9577}, {0, 19154}, {0, 38307}
		};

		static ssize_t mma8452_show_samp_freq_avail(struct device *dev,