ad7779_set_sampling_frequency
ret = ad7779_set_sampling_frequency(st, st->sampling_freq);
return ad7779_set_sampling_frequency(st, val);
ret = ad7779_set_sampling_frequency(st, AD7779_DEFAULT_SAMPLING_FREQ);
ret = ad7779_set_sampling_frequency(st, num_lanes * AD7779_DEFAULT_SAMPLING_1LINE);