linux-imx

/*

 * IEEE 1284.3 Parallel port daisy chain and multiplexor code

 * 

 * Copyright (C) 1999, 2000  Tim Waugh <tim@cyberelk.demon.co.uk>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version

 * 2 of the License, or (at your option) any later version.

 *

 * ??-12-1998: Initial implementation.

 * 31-01-1999: Make port-cloning transparent.

 * 13-02-1999: Move DeviceID technique from parport_probe.

 * 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.

 * 22-02-2000: Count devices that are actually detected.

 *

 * Any part of this program may be used in documents licensed under

 * the GNU Free Documentation License, Version 1.1 or any later version

 * published by the Free Software Foundation.

 */

​

#include <linux/module.h>

#include <linux/parport.h>

#include <linux/delay.h>

#include <linux/slab.h>

#include <linux/sched/signal.h>

​

#include <asm/current.h>

#include <linux/uaccess.h>

​

#undef DEBUG

​

#ifdef DEBUG

#define DPRINTK(stuff...) printk(stuff)

#else

#define DPRINTK(stuff...)

#endif

​

static struct daisydev {

    struct daisydev *next;

    struct parport *port;

    int daisy;

    int devnum;

} *topology = NULL;

static DEFINE_SPINLOCK(topology_lock);

​

static int numdevs;

​

/* Forward-declaration of lower-level functions. */

static int mux_present(struct parport *port);

static int num_mux_ports(struct parport *port);

static int select_port(struct parport *port);

static int assign_addrs(struct parport *port);

​

/* Add a device to the discovered topology. */

static void add_dev(int devnum, struct parport *port, int daisy)

{

    struct daisydev *newdev, **p;

    newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);

    if (newdev) {

        newdev->port = port;

        newdev->daisy = daisy;

        newdev->devnum = devnum;