drivers/staging/comedi/proc.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * /proc interface for comedi
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
 */

/*
 * This is some serious bloatware.
 *
 * Taken from Dave A.'s PCL-711 driver, 'cuz I thought it
 * was cool.
 */

#include "comedidev.h"
#include "comedi_internal.h"
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

static int comedi_read(struct seq_file *m, void *v)
{
	int i;
	int devices_q = 0;
	struct comedi_driver *driv;

	seq_printf(m, "comedi version " COMEDI_RELEASE "\nformat string: %s\n",
		   "\"%2d: %-20s %-20s %4d\", i, driver_name, board_name, n_subdevices");

	for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
		struct comedi_device *dev = comedi_dev_get_from_minor(i);

		if (!dev)
			continue;

		down_read(&dev->attach_lock);
		if (dev->attached) {
			devices_q = 1;
			seq_printf(m, "%2d: %-20s %-20s %4d\n",
				   i, dev->driver->driver_name,
				   dev->board_name, dev->n_subdevices);
		}
		up_read(&dev->attach_lock);
		comedi_dev_put(dev);
	}
	if (!devices_q)
		seq_puts(m, "no devices\n");

	mutex_lock(&comedi_drivers_list_lock);
	for (driv = comedi_drivers; driv; driv = driv->next) {
		seq_printf(m, "%s:\n", driv->driver_name);
		for (i = 0; i < driv->num_names; i++)
			seq_printf(m, " %s\n",
				   *(char **)((char *)driv->board_name +
					      i * driv->offset));

		if (!driv->num_names)
			seq_printf(m, " %s\n", driv->driver_name);
	}
	mutex_unlock(&comedi_drivers_list_lock);

	return 0;
}

/*
 * seq_file wrappers for procfile show routines.
 */
static int comedi_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, comedi_read, NULL);
}

static const struct file_operations comedi_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= comedi_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

void __init comedi_proc_init(void)
{
	if (!proc_create("comedi", 0444, NULL, &comedi_proc_fops))
		pr_warn("comedi: unable to create proc entry\n");
}

void comedi_proc_cleanup(void)
{
	remove_proc_entry("comedi", NULL);
}