AD3552R_GAIN_SCALE
tmp = (1024 * gn + AD3552R_GAIN_SCALE * offset) * common;
tmp = div_s64(tmp, 1024 * AD3552R_GAIN_SCALE);
tmp = (1024 * gp - AD3552R_GAIN_SCALE * offset) * common;
tmp = div_s64(tmp, 1024 * AD3552R_GAIN_SCALE);