diff options
| author |   Abhash Jha <abhashkumarjha123@gmail.com> | 2024-08-14 17:01:34 +0530 |
|---|---|---|
| committer |   Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2024-08-17 15:38:14 +0100 |
| commit | 4bd7e5ce519a9f1de1a58fb10438e45aa9cc85ca (patch) | |
| tree | bdc1f6e60a5a09b79bb5d3509027f670a7ebbaf7 | |
| parent | iio: light: ltr390: Add ALS channel and support for gain and resolution (diff) | |
| download | wireguard-linux-4bd7e5ce519a9f1de1a58fb10438e45aa9cc85ca.tar.xz wireguard-linux-4bd7e5ce519a9f1de1a58fb10438e45aa9cc85ca.zip | |
iio: light: ltr390: Calculate 'counts_per_uvi' dynamically
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>
Diffstat (limited to '')
| -rw-r--r-- | drivers/iio/light/ltr390.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/iio/light/ltr390.c b/drivers/iio/light/ltr390.c index 16e06f2ab878..7e58b50f3660 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: |