| Message ID | 9352ade3afee830795315b5931dfb316853dc094.1524247563.git.davidjulianveenstra@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 20 Apr 2018 21:31:48 +0200 David Veenstra <davidjulianveenstra@gmail.com> wrote: > A fractional scaling factor of approximately 2 * Pi / (2^12 -1) is added, > to scale the 12-bits angular position to radians. > > Signed-off-by: David Veenstra <davidjulianveenstra@gmail.com> > --- > Changes in v2: > - This patch replaces the patch that changed the > the channel for angular position to inclination > channel. > > drivers/staging/iio/resolver/ad2s1200.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c > index 6c56257be3b1..4f5dd28b174a 100644 > --- a/drivers/staging/iio/resolver/ad2s1200.c > +++ b/drivers/staging/iio/resolver/ad2s1200.c > @@ -71,6 +71,17 @@ 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) ~= 2 * 103993 / (33102 * 0xFFF) > + * > + * Since there only fit 3 whole radians in 360 degrees, > + * usage of iio_convert_raw_to_processed for this > + * channel will be highly inaccurate. > + */ > + *val = 103993; > + *val2 = 16551 * 0xFFF; > + return IIO_VAL_FRACTIONAL; Again, use IIO_VAL_INT_PLUS_MICRO and specify it as a decimal. There is no need to jump through these hoops when we are unlikely to have any users that need to keep to integer only maths. Thanks, Jonathan > case IIO_ANGL_VEL: > /* > * 2 * Pi ~= 2 * 103993 / 33102 > @@ -133,6 +144,7 @@ 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, -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c index 6c56257be3b1..4f5dd28b174a 100644 --- a/drivers/staging/iio/resolver/ad2s1200.c +++ b/drivers/staging/iio/resolver/ad2s1200.c @@ -71,6 +71,17 @@ 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) ~= 2 * 103993 / (33102 * 0xFFF) + * + * Since there only fit 3 whole radians in 360 degrees, + * usage of iio_convert_raw_to_processed for this + * channel will be highly inaccurate. + */ + *val = 103993; + *val2 = 16551 * 0xFFF; + return IIO_VAL_FRACTIONAL; case IIO_ANGL_VEL: /* * 2 * Pi ~= 2 * 103993 / 33102 @@ -133,6 +144,7 @@ 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,
A fractional scaling factor of approximately 2 * Pi / (2^12 -1) is added, to scale the 12-bits angular position to radians. Signed-off-by: David Veenstra <davidjulianveenstra@gmail.com> --- Changes in v2: - This patch replaces the patch that changed the the channel for angular position to inclination channel. drivers/staging/iio/resolver/ad2s1200.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)