regulator_lock_nested
regulator_lock_nested(rdev, NULL);
ret = regulator_lock_nested(rdev1, ww_ctx);
ret = regulator_lock_nested(rdev2, ww_ctx);
ret = regulator_lock_nested(contended, ww_ctx);
err = regulator_lock_nested(c_rdev, ww_ctx);
ret = regulator_lock_nested(rdev, lock_data->ww_ctx);