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iio: light: ltr390: Calculate 'counts_per_uvi' dynamically

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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@gmail.com>
Link: https://patch.msgid.link/20240814113135.14575-3-abhashkumarjha123@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Abhash Jha 2024-08-14 17:01:34 +05:30 committed by Jonathan Cameron
parent 14e0d914a8
commit 4bd7e5ce51
1 changed files with 12 additions and 2 deletions
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14
drivers/iio/light/ltr390.c
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@ -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: