Function saul_reg_read

pub unsafe extern "C" fn saul_reg_read(
    dev: *mut saul_reg_t,
    res: *mut phydat_t,
) -> c_int

@brief Read data from the given device

@param[in] dev device to read from @param[out] res location to store the results in

@return the number of data elements read to @p res [1-3] @return -ENODEV if given device is invalid @return -ENOTSUP if read operation is not supported by the device @return -ECANCELED on device errors