iio_backend_oversampling_ratio_set
ret = iio_backend_oversampling_ratio_set(st->back, 0, osr);
ret = iio_backend_oversampling_ratio_set(st->back, chan->scan_index, dec_rate);
EXPORT_SYMBOL_NS_GPL(iio_backend_oversampling_ratio_set, "IIO_BACKEND");
int iio_backend_oversampling_ratio_set(struct iio_backend *back,