iio: fix scale application in iio_convert_raw_to_processed_unlocked

When the scale_type is IIO_VAL_INT_PLUS_MICRO or IIO_VAL_INT_PLUS_NANO
the scale passed as argument is only applied to the fractional part of
the value. Fix it by also multiplying the integer part by the scale
provided.

Fixes: 48e44ce0 ("iio:inkern: Add function to read the processed value")
Signed-off-by: Matteo Martelli <matteomartelli3@gmail.com>
Link: https://patch.msgid.link/20240730-iio-fix-scale-v1-1-6246638c8daa@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/inkern.c

@@ -647,17 +647,17 @@ static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 		break;
 	case IIO_VAL_INT_PLUS_MICRO:
 		if (scale_val2 < 0)
-			*processed = -raw64 * scale_val;
+			*processed = -raw64 * scale_val * scale;
 		else
-			*processed = raw64 * scale_val;
+			*processed = raw64 * scale_val * scale;
 		*processed += div_s64(raw64 * (s64)scale_val2 * scale,
 				      1000000LL);
 		break;
 	case IIO_VAL_INT_PLUS_NANO:
 		if (scale_val2 < 0)
-			*processed = -raw64 * scale_val;
+			*processed = -raw64 * scale_val * scale;
 		else
-			*processed = raw64 * scale_val;
+			*processed = raw64 * scale_val * scale;
 		*processed += div_s64(raw64 * (s64)scale_val2 * scale,
 				      1000000000LL);
 		break;