[v2 07/19] staging: iio: resolver: ad2s1210: implement IIO_CHAN_INFO_SCALE

David Lechner
2023-09-21T21:30:17Z

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>
---
drivers/staging/iio/resolver/ad2s1210.c | 107 ++++++++++++++++--------
1 file changed, 72 insertions(+), 35 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index 985b8fecd65a..95d43b241a75 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -458,56 +458,91 @@ static ssize_t ad2s1210_store_reg(struct device *dev,
return ret < 0 ? ret : len;
}

+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 m)
+ long mask)
{
struct ad2s1210_state *st = iio_priv(indio_dev);
int ret = 0;

- mutex_lock(&st->lock);
- gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
- /* delay (6 * tck + 20) nano seconds */
- udelay(1);
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&st->lock);
+ gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
+ /* delay (6 * tck + 20) nano seconds */
+ udelay(1);
+
+ switch (chan->type) {
+ case IIO_ANGL:
+ ad2s1210_set_mode(MOD_POS, st);
+ break;
+ case IIO_ANGL_VEL:
+ ad2s1210_set_mode(MOD_VEL, st);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ if (ret < 0)
+ goto error_info_raw;
+ ret = spi_read(st->sdev, st->rx, 2);
+ if (ret < 0)
+ goto error_info_raw;
+
+ switch (chan->type) {
+ case IIO_ANGL:
+ *val = be16_to_cpup((__be16 *)st->rx);
+ ret = IIO_VAL_INT;
+ break;
+ case IIO_ANGL_VEL:
+ *val = (s16)be16_to_cpup((__be16 *)st->rx);
+ ret = IIO_VAL_INT;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }

- switch (chan->type) {
- case IIO_ANGL:
- ad2s1210_set_mode(MOD_POS, st);
- break;
- case IIO_ANGL_VEL:
- ad2s1210_set_mode(MOD_VEL, st);
- break;
- default:
- ret = -EINVAL;
+error_info_raw:
+ gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
+ /* delay (2 * tck + 20) nano seconds */
+ udelay(1);
+ mutex_unlock(&st->lock);
break;
- }
- if (ret < 0)
- goto error_ret;
- ret = spi_read(st->sdev, st->rx, 2);
- if (ret < 0)
- goto error_ret;

- switch (chan->type) {
- case IIO_ANGL:
- *val = be16_to_cpup((__be16 *)st->rx);
- ret = IIO_VAL_INT;
- break;
- case IIO_ANGL_VEL:
- *val = (s16)be16_to_cpup((__be16 *)st->rx);
- ret = IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_ANGL:
+ /* approx 0.3 arc min converted to radians */
+ *val = 0;
+ *val2 = 95874;
+ ret = IIO_VAL_INT_PLUS_NANO;
+ break;
+ case IIO_ANGL_VEL:
+ *val = st->fclkin;
+ *val2 = ad2s1210_velocity_scale[st->resolution];
+ ret = IIO_VAL_FRACTIONAL;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
break;
+
default:
ret = -EINVAL;
break;
}

-error_ret:
- gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
- /* delay (2 * tck + 20) nano seconds */
- udelay(1);
- mutex_unlock(&st->lock);
return ret;
}

@@ -549,12 +584,14 @@ 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),
}
};

--
2.34.1