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| author | Martin Fuzzey <mfuzzey@parkeon.com> | 2014-11-07 13:54:00 +0000 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2014-07-12 13:18:55 +0100 |
| commit | 71702e6e52c8312f4c6797a9787d0f8b5656156f (patch) | |
| tree | 21bf3ee4d0166292776d5097f10794d138aa8248 | |
| parent | 78b3321610bf920d7fceb1a0236faa881be0bcf3 (diff) | |
| download | op-kernel-dev-71702e6e52c8312f4c6797a9787d0f8b5656156f.zip op-kernel-dev-71702e6e52c8312f4c6797a9787d0f8b5656156f.tar.gz | |
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
| -rw-r--r-- | drivers/iio/accel/mma8452.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c index 17aeea1..2a5fa9a 100644 --- a/drivers/iio/accel/mma8452.c +++ b/drivers/iio/accel/mma8452.c @@ -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, |
