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iio: mma8452: Use correct acceleration units.

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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
This commit is contained in:
Martin Fuzzey 2014-11-07 13:54:00 +00:00 committed by Jonathan Cameron
parent 78b3321610
commit 71702e6e52
1 changed files with 7 additions and 1 deletions
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8
drivers/iio/accel/mma8452.c
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@ -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,