nec7210_ioport_write_byte
nec_priv->write_byte = nec7210_ioport_write_byte;
void nec7210_ioport_write_byte(struct nec7210_priv *priv, u8 data, unsigned int register_num);
nec_priv->write_byte = nec7210_ioport_write_byte;
EXPORT_SYMBOL(nec7210_ioport_write_byte);
nec_priv->write_byte = nec7210_ioport_write_byte;