iio: light: veml6030: fix microlux value calculation

commit 63dd163 upstream.

The raw value conversion to obtain a measurement in lux as
INT_PLUS_MICRO does not calculate the decimal part properly to display
it as micro (in this case microlux). It only calculates the module to
obtain the decimal part from a resolution that is 10000 times the
provided in the datasheet (0.5376 lux/cnt for the veml6030). The
resulting value must still be multiplied by 100 to make it micro.

This bug was introduced with the original implementation of the driver.

Only the illuminance channel is fixed becuase the scale is non sensical
for the intensity channels anyway.

Cc: [email protected]
Fixes: 7b779f5 ("iio: light: add driver for veml6030 ambient light sensor")
Signed-off-by: Javier Carrasco <[email protected]>
Link: https://patch.msgid.link/20241016-veml6030-fix-processed-micro-v1-1-4a5644796437@gmail.com
Signed-off-by: Jonathan Cameron <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/iio/light/veml6030.c

@@ -522,7 +522,7 @@ static int veml6030_read_raw(struct iio_dev *indio_dev,
 			}
 			if (mask == IIO_CHAN_INFO_PROCESSED) {
 				*val = (reg * data->cur_resolution) / 10000;
-				*val2 = (reg * data->cur_resolution) % 10000;
+				*val2 = (reg * data->cur_resolution) % 10000 * 100;
 				return IIO_VAL_INT_PLUS_MICRO;
 			}
 			*val = reg;