centos man page for parport_write

PARPORT_WRITE(9)					       Parallel Port Devices						  PARPORT_WRITE(9)

NAME
       parport_write - write a block of data to a parallel port

SYNOPSIS
       ssize_t parport_write(struct parport * port, const void * buffer, size_t len);

ARGUMENTS
       port
	   port to write to

       buffer
	   data buffer (in kernel space)

       len
	   number of bytes of data to transfer

DESCRIPTION
       This will write up to len bytes of buffer to the port specified, using the IEEE 1284 transfer mode most recently negotiated to (using
       parport_negotiate), as long as that mode supports forward transfers (host to peripheral).

       It is the caller's responsibility to ensure that the first len bytes of buffer are valid.

       This function returns the number of bytes transferred (if zero or positive), or else an error code.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							  PARPORT_WRITE(9)