spi_xmit
r = spi_xmit(spi_dev, addr + j, tx_size, SPI_DIR_RX);
return spi_xmit(spi_dev, addr + j, extra, SPI_DIR_RX);
r = spi_xmit(spi_dev, (void *)addr + j, tx_size, SPI_DIR_TX);
r = spi_xmit(spi_dev, (void *)addr + j, extra, SPI_DIR_TX);
return spi_xmit(spi_dev, padding, sizeof(padding), SPI_DIR_TX);