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staging: iio: ad2s1200: Add scaling factor for angular velocity channel

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The sysfs iio ABI states radians per second is expected as the unit for
angular velocity, but the 12-bit angular velocity register has
revolution per seconds as its unit. So a scaling factor of approximately
2 * Pi is added to the angular velocity channel.

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 20:23:01 +02:00 committed by Jonathan Cameron
parent 2363c010ce
commit d3e6ed8416
1 changed files with 43 additions and 24 deletions
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67
drivers/staging/iio/resolver/ad2s1200.c
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@ -55,37 +55,55 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
struct ad2s1200_state *st = iio_priv(indio_dev);
int ret;
mutex_lock(&st->lock);
gpiod_set_value(st->sample, 0);
switch (m) {
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_ANGL_VEL:
/* 2 * Pi ~= 6.283185 */
*val = 6;
*val2 = 283185;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
break;
case IIO_CHAN_INFO_RAW:
mutex_lock(&st->lock);
gpiod_set_value(st->sample, 0);
/* delay (6 * AD2S1200_TSCLK + 20) nano seconds */
udelay(1);
gpiod_set_value(st->sample, 1);
gpiod_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
/* delay (6 * AD2S1200_TSCLK + 20) nano seconds */
udelay(1);
gpiod_set_value(st->sample, 1);
gpiod_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
ret = spi_read(st->sdev, &st->rx, 2);
if (ret < 0) {
ret = spi_read(st->sdev, &st->rx, 2);
if (ret < 0) {
mutex_unlock(&st->lock);
return ret;
}
switch (chan->type) {
case IIO_ANGL:
*val = be16_to_cpup(&st->rx) >> 4;
break;
case IIO_ANGL_VEL:
*val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11);
break;
default:
mutex_unlock(&st->lock);
return -EINVAL;
}
/* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */
udelay(1);
mutex_unlock(&st->lock);
return ret;
}
switch (chan->type) {
case IIO_ANGL:
*val = be16_to_cpup(&st->rx) >> 4;
break;
case IIO_ANGL_VEL:
*val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11);
break;
return IIO_VAL_INT;
default:
mutex_unlock(&st->lock);
return -EINVAL;
break;
}
/* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */
udelay(1);
mutex_unlock(&st->lock);
return IIO_VAL_INT;
return -EINVAL;
}
static const struct iio_chan_spec ad2s1200_channels[] = {
@ -99,6 +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),
}
};