counts_per_uvi depends on the current value of gain and resolution.
Hence, we cannot use the hardcoded value 96.
The `counts_per_uvi` function gives the count based on the current gain
and resolution (integration time).
Signed-off-by: Abhash Jha <abhashkumarjha123@xxxxxxxxx>
---
drivers/iio/light/ltr390.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/light/ltr390.c b/drivers/iio/light/ltr390.c
index 16e06f2ab..7e58b50f3 100644
--- a/drivers/iio/light/ltr390.c
+++ b/drivers/iio/light/ltr390.c
@@ -46,6 +46,8 @@
#define LTR390_UVS_MODE BIT(3)
#define LTR390_SENSOR_ENABLE BIT(1)
+#define LTR390_FRACTIONAL_PRECISION 100
+
/*
* At 20-bit resolution (integration time: 400ms) and 18x gain, 2300 counts of
* the sensor are equal to 1 UV Index [Datasheet Page#8].
@@ -125,6 +127,14 @@ static int ltr390_set_mode(struct ltr390_data *data, enum ltr390_mode mode)
return 0;
}
+static int ltr390_counts_per_uvi(struct ltr390_data *data)
+{
+ const int orig_gain = 18;
+ const int orig_int_time = 400;
+
+ return DIV_ROUND_CLOSEST(23 * data->gain * data->int_time_us, 10 * orig_gain * orig_int_time);
+}
+
static int ltr390_read_raw(struct iio_dev *iio_device,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
@@ -164,8 +174,8 @@ static int ltr390_read_raw(struct iio_dev *iio_device,
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_UVINDEX:
- *val = LTR390_WINDOW_FACTOR;
- *val2 = LTR390_COUNTS_PER_UVI;
+ *val = LTR390_WINDOW_FACTOR * LTR390_FRACTIONAL_PRECISION;
+ *val2 = ltr390_counts_per_uvi(data);
return IIO_VAL_FRACTIONAL;
case IIO_LIGHT:
--
2.43.0
