[PATCH v3 08/27] staging: iio: resolver: ad2s1210: implement IIO_CHAN_INFO_SCALE

David Lechner
2023-09-29T17:26:27Z

From: David Lechner <david@lechnology.com>

From: David Lechner <dlechner@baylibre.com>

This adds an implementation of IIO_CHAN_INFO_SCALE to the ad2s1210
resolver driver. This allows userspace to get the scale factor for the
raw values.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---

v3 changes:
* Split ad2s1210_read_raw() into two functions to reduce complexity.
* Use early return instead of break in switch statements.

drivers/staging/iio/resolver/ad2s1210.c | 53 ++++++++++++++++++++++++++++-----
1 file changed, 45 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index f9774dff2df4..a710598a64f0 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -461,13 +461,10 @@ static ssize_t ad2s1210_store_reg(struct device *dev,
return ret < 0 ? ret : len;
}

-static int ad2s1210_read_raw(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan,
- int *val,
- int *val2,
- long m)
+static int ad2s1210_single_conversion(struct ad2s1210_state *st,
+ struct iio_chan_spec const *chan,
+ int *val)
{
- struct ad2s1210_state *st = iio_priv(indio_dev);
int ret = 0;

mutex_lock(&st->lock);
@@ -514,6 +511,44 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
return ret;
}

+static const int ad2s1210_velocity_scale[] = {
+ 17089132, /* 8.192MHz / (2*pi * 2500 / 2^15) */
+ 42722830, /* 8.192MHz / (2*pi * 1000 / 2^15) */
+ 85445659, /* 8.192MHz / (2*pi * 500 / 2^15) */
+ 341782638, /* 8.192MHz / (2*pi * 125 / 2^15) */
+};
+
+static int ad2s1210_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long mask)
+{
+ struct ad2s1210_state *st = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ return ad2s1210_single_conversion(st, chan, val);
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_ANGL:
+ /* approx 0.3 arc min converted to radians */
+ *val = 0;
+ *val2 = 95874;
+ return IIO_VAL_INT_PLUS_NANO;
+ case IIO_ANGL_VEL:
+ *val = st->fclkin;
+ *val2 = ad2s1210_velocity_scale[st->resolution];
+ return IIO_VAL_FRACTIONAL;
+ default:
+ return -EINVAL;
+ }
+
+ default:
+ return -EINVAL;
+ }
+}
+
static IIO_DEVICE_ATTR(fclkin, 0644,
ad2s1210_show_fclkin, ad2s1210_store_fclkin, 0);
static IIO_DEVICE_ATTR(fexcit, 0644,
@@ -552,12 +587,14 @@ static const struct iio_chan_spec ad2s1210_channels[] = {
.type = IIO_ANGL,
.indexed = 1,
.channel = 0,
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
}, {
.type = IIO_ANGL_VEL,
.indexed = 1,
.channel = 0,
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
}
};

--
2.42.0