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staging: iio: ad2s1200: Add scaling factor for angle channel

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A scaling factor of approximately 2 * Pi / (2^12 -1) is added,
to scale the 12-bits angular position to radians.

A return type of IIO_VAL_INT_PLUS_NANO is used, so that the scale of
both the angle channel and angular velocity channel has 7 significant
digits.

Signed-off-by: David Veenstra <davidjulianveenstra@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
David Veenstra 2018-05-18 20:23:14 +02:00 committed by Jonathan Cameron
parent d3e6ed8416
commit f9db7370be
1 changed files with 6 additions and 0 deletions
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6
drivers/staging/iio/resolver/ad2s1200.c
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@ -58,6 +58,11 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
switch (m) {
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_ANGL:
/* 2 * Pi / (2^12 - 1) ~= 0.001534355 */
*val = 0;
*val2 = 1534355;
return IIO_VAL_INT_PLUS_NANO;
case IIO_ANGL_VEL:
/* 2 * Pi ~= 6.283185 */
*val = 6;
@ -112,6 +117,7 @@ static const struct iio_chan_spec ad2s1200_channels[] = {
.indexed = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
}, {
.type = IIO_ANGL_VEL,
.indexed = 1,