On Fri, 18 May 2018 20:23:01 +0200
David Veenstra <davidjulianveenstra@xxxxxxxxx> wrote:
> 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@xxxxxxxxx>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.
Thanks,
Jonathan
> ---
> Changes in v4:
> - Changed rps to revolutions per second in commit message
> to prevent confusion.
>
> drivers/staging/iio/resolver/ad2s1200.c | 71 ++++++++++++++++---------
> 1 file changed, 45 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c
> index 67d9747f88a6..7b8af558e921 100644
> --- a/drivers/staging/iio/resolver/ad2s1200.c
> +++ b/drivers/staging/iio/resolver/ad2s1200.c
> @@ -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);
> -
> - /* 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) {
> + 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));
> +
> + 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),
> }
> };
>
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