w1.c

电源的驱动程序源代码 a useful driver program

/*
 *	w1.c
 *
 * Copyright (c) 2004 Evgeniy Polyakov <[e-mail]>
 *
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/sched.h>

#include <asm/atomic.h>

#include "w1.h"
#include "w1_io.h"
#include "w1_log.h"
#include "w1_int.h"
#include "w1_family.h"
#include "w1_netlink.h"

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Evgeniy Polyakov <[e-mail]>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");

static int w1_timeout = 10;
static int w1_control_timeout = 1;
int w1_max_slave_count = 10;
int w1_max_slave_ttl = 10;

module_param_named(timeout, w1_timeout, int, 0);
module_param_named(control_timeout, w1_control_timeout, int, 0);
module_param_named(max_slave_count, w1_max_slave_count, int, 0);
module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);

DEFINE_SPINLOCK(w1_mlock);
LIST_HEAD(w1_masters);

static pid_t control_thread;
static int control_needs_exit;
static DECLARE_COMPLETION(w1_control_complete);

static int w1_master_match(struct device *dev, struct device_driver *drv)
{
	return 1;
}

static int w1_master_probe(struct device *dev)
{
	return -ENODEV;
}

static void w1_master_release(struct device *dev)
{
	struct w1_master *md = dev_to_w1_master(dev);

	dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);

	dev_fini_netlink(md);
	memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
	kfree(md);
}

static void w1_slave_release(struct device *dev)
{
	struct w1_slave *sl = dev_to_w1_slave(dev);

	dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);

	while (atomic_read(&sl->refcnt)) {
		dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
				sl->name, atomic_read(&sl->refcnt));
		if (msleep_interruptible(1000))
			flush_signals(current);
	}

	w1_family_put(sl->family);
	sl->master->slave_count--;

	complete(&sl->released);
}

static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct w1_slave *sl = dev_to_w1_slave(dev);

	return sprintf(buf, "%s\n", sl->name);
}

static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
{
	struct w1_slave *sl = kobj_to_w1_slave(kobj);

	atomic_inc(&sl->refcnt);
	if (off > 8) {
		count = 0;
	} else {
		if (off + count > 8)
			count = 8 - off;

		memcpy(buf, (u8 *)&sl->reg_num, count);
	}
	atomic_dec(&sl->refcnt);

	return count;
}

static struct device_attribute w1_slave_attr_name =
	__ATTR(name, S_IRUGO, w1_slave_read_name, NULL);

static struct bin_attribute w1_slave_attr_bin_id = {
      .attr = {
              .name = "id",
              .mode = S_IRUGO,
              .owner = THIS_MODULE,
      },
      .size = 8,
      .read = w1_slave_read_id,
};

/* Default family */
static struct w1_family w1_default_family;

static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);

static struct bus_type w1_bus_type = {
	.name = "w1",
	.match = w1_master_match,
	.hotplug = w1_hotplug,
};

struct device_driver w1_master_driver = {
	.name = "w1_master_driver",
	.bus = &w1_bus_type,
	.probe = w1_master_probe,
};

struct device w1_master_device = {
	.parent = NULL,
	.bus = &w1_bus_type,
	.bus_id = "w1 bus master",
	.driver = &w1_master_driver,
	.release = &w1_master_release
};

struct device_driver w1_slave_driver = {
	.name = "w1_slave_driver",
	.bus = &w1_bus_type,
};

struct device w1_slave_device = {
	.parent = NULL,
	.bus = &w1_bus_type,
	.bus_id = "w1 bus slave",
	.driver = &w1_slave_driver,
	.release = &w1_slave_release
};

static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct w1_master *md = dev_to_w1_master(dev);
	ssize_t count;

	if (down_interruptible (&md->mutex))
		return -EBUSY;

	count = sprintf(buf, "%s\n", md->name);

	up(&md->mutex);

	return count;
}

static ssize_t w1_master_attribute_store_search(struct device * dev,
						struct device_attribute *attr,
						const char * buf, size_t count)
{
	struct w1_master *md = dev_to_w1_master(dev);

	if (down_interruptible (&md->mutex))
		return -EBUSY;

	md->search_count = simple_strtol(buf, NULL, 0);

	up(&md->mutex);

	return count;
}

static ssize_t w1_master_attribute_show_search(struct device *dev,
					       struct device_attribute *attr,
					       char *buf)
{
	struct w1_master *md = dev_to_w1_master(dev);
	ssize_t count;

	if (down_interruptible (&md->mutex))
		return -EBUSY;

	count = sprintf(buf, "%d\n", md->search_count);

	up(&md->mutex);

	return count;
}

static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct w1_master *md = dev_to_w1_master(dev);
	ssize_t count;

	if (down_interruptible(&md->mutex))
		return -EBUSY;

	count = sprintf(buf, "0x%p\n", md->bus_master);

	up(&md->mutex);
	return count;
}

static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
{
	ssize_t count;
	count = sprintf(buf, "%d\n", w1_timeout);
	return count;
}

static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct w1_master *md = dev_to_w1_master(dev);
	ssize_t count;

	if (down_interruptible(&md->mutex))
		return -EBUSY;

	count = sprintf(buf, "%d\n", md->max_slave_count);

	up(&md->mutex);
	return count;
}

static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct w1_master *md = dev_to_w1_master(dev);
	ssize_t count;

	if (down_interruptible(&md->mutex))
		return -EBUSY;

	count = sprintf(buf, "%lu\n", md->attempts);

	up(&md->mutex);
	return count;
}

static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct w1_master *md = dev_to_w1_master(dev);
	ssize_t count;

	if (down_interruptible(&md->mutex))
		return -EBUSY;

	count = sprintf(buf, "%d\n", md->slave_count);

	up(&md->mutex);
	return count;
}

static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct w1_master *md = dev_to_w1_master(dev);
	int c = PAGE_SIZE;

	if (down_interruptible(&md->mutex))
		return -EBUSY;

	if (md->slave_count == 0)
		c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
	else {
		struct list_head *ent, *n;
		struct w1_slave *sl;

		list_for_each_safe(ent, n, &md->slist) {
			sl = list_entry(ent, struct w1_slave, w1_slave_entry);

			c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
		}
	}

	up(&md->mutex);

	return PAGE_SIZE - c;
}

#define W1_MASTER_ATTR_RO(_name, _mode)				\
	struct device_attribute w1_master_attribute_##_name =	\
		__ATTR(w1_master_##_name, _mode,		\
		       w1_master_attribute_show_##_name, NULL)

#define W1_MASTER_ATTR_RW(_name, _mode)				\
	struct device_attribute w1_master_attribute_##_name =	\
		__ATTR(w1_master_##_name, _mode,		\
		       w1_master_attribute_show_##_name,	\
		       w1_master_attribute_store_##_name)

static W1_MASTER_ATTR_RO(name, S_IRUGO);
static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);

static struct attribute *w1_master_default_attrs[] = {
	&w1_master_attribute_name.attr,
	&w1_master_attribute_slaves.attr,
	&w1_master_attribute_slave_count.attr,
	&w1_master_attribute_max_slave_count.attr,
	&w1_master_attribute_attempts.attr,
	&w1_master_attribute_timeout.attr,
	&w1_master_attribute_pointer.attr,
	&w1_master_attribute_search.attr,
	NULL
};

static struct attribute_group w1_master_defattr_group = {
	.attrs = w1_master_default_attrs,
};

int w1_create_master_attributes(struct w1_master *master)
{
	return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
}

void w1_destroy_master_attributes(struct w1_master *master)
{
	sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
}

#ifdef CONFIG_HOTPLUG
static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
{
	struct w1_master *md = NULL;
	struct w1_slave *sl = NULL;
	char *event_owner, *name;
	int err, cur_index=0, cur_len=0;

	if (dev->driver == &w1_master_driver) {
		md = container_of(dev, struct w1_master, dev);
		event_owner = "master";
		name = md->name;
	} else if (dev->driver == &w1_slave_driver) {
		sl = container_of(dev, struct w1_slave, dev);
		event_owner = "slave";
		name = sl->name;
	} else {
		dev_dbg(dev, "Unknown hotplug event.\n");
		return -EINVAL;
	}

	dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);

	if (dev->driver != &w1_slave_driver || !sl)
		return 0;

	err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
	if (err)
		return err;

	err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
	if (err)
		return err;

	return 0;
};
#else
static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
{
	return 0;
}
#endif

static int __w1_attach_slave_device(struct w1_slave *sl)
{
	int err;

	sl->dev.parent = &sl->master->dev;
	sl->dev.driver = &w1_slave_driver;
	sl->dev.bus = &w1_bus_type;
	sl->dev.release = &w1_slave_release;

	snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
		 "%02x-%012llx",
		 (unsigned int) sl->reg_num.family,
		 (unsigned long long) sl->reg_num.id);
	snprintf(&sl->name[0], sizeof(sl->name),
		 "%02x-%012llx",
		 (unsigned int) sl->reg_num.family,
		 (unsigned long long) sl->reg_num.id);

	dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__, &sl->dev.bus_id[0]);

	err = device_register(&sl->dev);
	if (err < 0) {
		dev_err(&sl->dev,
			"Device registration [%s] failed. err=%d\n",
			sl->dev.bus_id, err);
		return err;
	}

	/* Create "name" entry */
	err = device_create_file(&sl->dev, &w1_slave_attr_name);
	if (err < 0) {
		dev_err(&sl->dev,
			"sysfs file creation for [%s] failed. err=%d\n",
			sl->dev.bus_id, err);
		goto out_unreg;
	}

	/* Create "id" entry */
	err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
	if (err < 0) {
		dev_err(&sl->dev,
			"sysfs file creation for [%s] failed. err=%d\n",
			sl->dev.bus_id, err);
		goto out_rem1;
	}

	/* if the family driver needs to initialize something... */
	if (sl->family->fops && sl->family->fops->add_slave &&
	    ((err = sl->family->fops->add_slave(sl)) < 0)) {
		dev_err(&sl->dev,
			"sysfs file creation for [%s] failed. err=%d\n",