Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1284 insertions, 0 deletions

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
new file mode 100644
index 000000000..2eee26b7f
--- /dev/null
+++ b/drivers/w1/w1.c
@@ -0,0 +1,1284 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
+ */
+
+#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 <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/hwmon.h>
+#include <linux/of.h>
+
+#include <linux/atomic.h>
+
+#include "w1_internal.h"
+#include "w1_netlink.h"
+
+#define W1_FAMILY_DEFAULT	0
+#define W1_FAMILY_DS28E04       0x1C /* for crc quirk */
+
+
+static int w1_timeout = 10;
+module_param_named(timeout, w1_timeout, int, 0);
+MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");
+
+static int w1_timeout_us = 0;
+module_param_named(timeout_us, w1_timeout_us, int, 0);
+MODULE_PARM_DESC(timeout_us,
+		 "time in microseconds between automatic slave searches");
+
+/* A search stops when w1_max_slave_count devices have been found in that
+ * search.  The next search will start over and detect the same set of devices
+ * on a static 1-wire bus.  Memory is not allocated based on this number, just
+ * on the number of devices known to the kernel.  Having a high number does not
+ * consume additional resources.  As a special case, if there is only one
+ * device on the network and w1_max_slave_count is set to 1, the device id can
+ * be read directly skipping the normal slower search process.
+ */
+int w1_max_slave_count = 64;
+module_param_named(max_slave_count, w1_max_slave_count, int, 0);
+MODULE_PARM_DESC(max_slave_count,
+	"maximum number of slaves detected in a search");
+
+int w1_max_slave_ttl = 10;
+module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
+MODULE_PARM_DESC(slave_ttl,
+	"Number of searches not seeing a slave before it will be removed");
+
+DEFINE_MUTEX(w1_mlock);
+LIST_HEAD(w1_masters);
+
+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);
+	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 [%p]\n", __func__, sl->name, sl);
+
+	w1_family_put(sl->family);
+	sl->master->slave_count--;
+}
+
+static ssize_t name_show(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 DEVICE_ATTR_RO(name);
+
+static ssize_t id_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(dev);
+	ssize_t count = sizeof(sl->reg_num);
+
+	memcpy(buf, (u8 *)&sl->reg_num, count);
+	return count;
+}
+static DEVICE_ATTR_RO(id);
+
+static struct attribute *w1_slave_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_id.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(w1_slave);
+
+/* Default family */
+
+static ssize_t rw_write(struct file *filp, struct kobject *kobj,
+			struct bin_attribute *bin_attr, char *buf, loff_t off,
+			size_t count)
+{
+	struct w1_slave *sl = kobj_to_w1_slave(kobj);
+
+	mutex_lock(&sl->master->mutex);
+	if (w1_reset_select_slave(sl)) {
+		count = 0;
+		goto out_up;
+	}
+
+	w1_write_block(sl->master, buf, count);
+
+out_up:
+	mutex_unlock(&sl->master->mutex);
+	return count;
+}
+
+static ssize_t rw_read(struct file *filp, struct kobject *kobj,
+		       struct bin_attribute *bin_attr, char *buf, loff_t off,
+		       size_t count)
+{
+	struct w1_slave *sl = kobj_to_w1_slave(kobj);
+
+	mutex_lock(&sl->master->mutex);
+	w1_read_block(sl->master, buf, count);
+	mutex_unlock(&sl->master->mutex);
+	return count;
+}
+
+static BIN_ATTR_RW(rw, PAGE_SIZE);
+
+static struct bin_attribute *w1_slave_bin_attrs[] = {
+	&bin_attr_rw,
+	NULL,
+};
+
+static const struct attribute_group w1_slave_default_group = {
+	.bin_attrs = w1_slave_bin_attrs,
+};
+
+static const struct attribute_group *w1_slave_default_groups[] = {
+	&w1_slave_default_group,
+	NULL,
+};
+
+static const struct w1_family_ops w1_default_fops = {
+	.groups		= w1_slave_default_groups,
+};
+
+static struct w1_family w1_default_family = {
+	.fops = &w1_default_fops,
+};
+
+static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
+
+static struct bus_type w1_bus_type = {
+	.name = "w1",
+	.match = w1_master_match,
+	.uevent = w1_uevent,
+};
+
+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,
+	.init_name = "w1 bus master",
+	.driver = &w1_master_driver,
+	.release = &w1_master_release
+};
+
+static struct device_driver w1_slave_driver = {
+	.name = "w1_slave_driver",
+	.bus = &w1_bus_type,
+};
+
+#if 0
+struct device w1_slave_device = {
+	.parent = NULL,
+	.bus = &w1_bus_type,
+	.init_name = "w1 bus slave",
+	.driver = &w1_slave_driver,
+	.release = &w1_slave_release
+};
+#endif  /*  0  */
+
+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;
+
+	mutex_lock(&md->mutex);
+	count = sprintf(buf, "%s\n", md->name);
+	mutex_unlock(&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)
+{
+	long tmp;
+	struct w1_master *md = dev_to_w1_master(dev);
+	int ret;
+
+	ret = kstrtol(buf, 0, &tmp);
+	if (ret)
+		return ret;
+
+	mutex_lock(&md->mutex);
+	md->search_count = tmp;
+	mutex_unlock(&md->mutex);
+	/* Only wake if it is going to be searching. */
+	if (tmp)
+		wake_up_process(md->thread);
+
+	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;
+
+	mutex_lock(&md->mutex);
+	count = sprintf(buf, "%d\n", md->search_count);
+	mutex_unlock(&md->mutex);
+
+	return count;
+}
+
+static ssize_t w1_master_attribute_store_pullup(struct device *dev,
+						struct device_attribute *attr,
+						const char *buf, size_t count)
+{
+	long tmp;
+	struct w1_master *md = dev_to_w1_master(dev);
+	int ret;
+
+	ret = kstrtol(buf, 0, &tmp);
+	if (ret)
+		return ret;
+
+	mutex_lock(&md->mutex);
+	md->enable_pullup = tmp;
+	mutex_unlock(&md->mutex);
+
+	return count;
+}
+
+static ssize_t w1_master_attribute_show_pullup(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf)
+{
+	struct w1_master *md = dev_to_w1_master(dev);
+	ssize_t count;
+
+	mutex_lock(&md->mutex);
+	count = sprintf(buf, "%d\n", md->enable_pullup);
+	mutex_unlock(&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;
+
+	mutex_lock(&md->mutex);
+	count = sprintf(buf, "0x%p\n", md->bus_master);
+	mutex_unlock(&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_timeout_us(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	ssize_t count;
+	count = sprintf(buf, "%d\n", w1_timeout_us);
+	return count;
+}
+
+static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	int tmp;
+	struct w1_master *md = dev_to_w1_master(dev);
+
+	if (kstrtoint(buf, 0, &tmp) || tmp < 1)
+		return -EINVAL;
+
+	mutex_lock(&md->mutex);
+	md->max_slave_count = tmp;
+	/* allow each time the max_slave_count is updated */
+	clear_bit(W1_WARN_MAX_COUNT, &md->flags);
+	mutex_unlock(&md->mutex);
+
+	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;
+
+	mutex_lock(&md->mutex);
+	count = sprintf(buf, "%d\n", md->max_slave_count);
+	mutex_unlock(&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;
+
+	mutex_lock(&md->mutex);
+	count = sprintf(buf, "%lu\n", md->attempts);
+	mutex_unlock(&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;
+
+	mutex_lock(&md->mutex);
+	count = sprintf(buf, "%d\n", md->slave_count);
+	mutex_unlock(&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;
+	struct list_head *ent, *n;
+	struct w1_slave *sl = NULL;
+
+	mutex_lock(&md->list_mutex);
+
+	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);
+	}
+	if (!sl)
+		c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
+
+	mutex_unlock(&md->list_mutex);
+
+	return PAGE_SIZE - c;
+}
+
+static ssize_t w1_master_attribute_show_add(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	int c = PAGE_SIZE;
+	c -= snprintf(buf+PAGE_SIZE - c, c,
+		"write device id xx-xxxxxxxxxxxx to add slave\n");
+	return PAGE_SIZE - c;
+}
+
+static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
+	struct w1_reg_num *rn)
+{
+	unsigned int family;
+	unsigned long long id;
+	int i;
+	u64 rn64_le;
+
+	/* The CRC value isn't read from the user because the sysfs directory
+	 * doesn't include it and most messages from the bus search don't
+	 * print it either.  It would be unreasonable for the user to then
+	 * provide it.
+	 */
+	const char *error_msg = "bad slave string format, expecting "
+		"ff-dddddddddddd\n";
+
+	if (buf[2] != '-') {
+		dev_err(dev, "%s", error_msg);
+		return -EINVAL;
+	}
+	i = sscanf(buf, "%02x-%012llx", &family, &id);
+	if (i != 2) {
+		dev_err(dev, "%s", error_msg);
+		return -EINVAL;
+	}
+	rn->family = family;
+	rn->id = id;
+
+	rn64_le = cpu_to_le64(*(u64 *)rn);
+	rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
+
+#if 0
+	dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
+		  rn->family, (unsigned long long)rn->id, rn->crc);
+#endif
+
+	return 0;
+}
+
+/* Searches the slaves in the w1_master and returns a pointer or NULL.
+ * Note: must not hold list_mutex
+ */
+struct w1_slave *w1_slave_search_device(struct w1_master *dev,
+	struct w1_reg_num *rn)
+{
+	struct w1_slave *sl;
+	mutex_lock(&dev->list_mutex);
+	list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
+		if (sl->reg_num.family == rn->family &&
+				sl->reg_num.id == rn->id &&
+				sl->reg_num.crc == rn->crc) {
+			mutex_unlock(&dev->list_mutex);
+			return sl;
+		}
+	}
+	mutex_unlock(&dev->list_mutex);
+	return NULL;
+}
+
+static ssize_t w1_master_attribute_store_add(struct device *dev,
+						struct device_attribute *attr,
+						const char *buf, size_t count)
+{
+	struct w1_master *md = dev_to_w1_master(dev);
+	struct w1_reg_num rn;
+	struct w1_slave *sl;
+	ssize_t result = count;
+
+	if (w1_atoreg_num(dev, buf, count, &rn))
+		return -EINVAL;
+
+	mutex_lock(&md->mutex);
+	sl = w1_slave_search_device(md, &rn);
+	/* It would be nice to do a targeted search one the one-wire bus
+	 * for the new device to see if it is out there or not.  But the
+	 * current search doesn't support that.
+	 */
+	if (sl) {
+		dev_info(dev, "Device %s already exists\n", sl->name);
+		result = -EINVAL;
+	} else {
+		w1_attach_slave_device(md, &rn);
+	}
+	mutex_unlock(&md->mutex);
+
+	return result;
+}
+
+static ssize_t w1_master_attribute_show_remove(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	int c = PAGE_SIZE;
+	c -= snprintf(buf+PAGE_SIZE - c, c,
+		"write device id xx-xxxxxxxxxxxx to remove slave\n");
+	return PAGE_SIZE - c;
+}
+
+static ssize_t w1_master_attribute_store_remove(struct device *dev,
+						struct device_attribute *attr,
+						const char *buf, size_t count)
+{
+	struct w1_master *md = dev_to_w1_master(dev);
+	struct w1_reg_num rn;
+	struct w1_slave *sl;
+	ssize_t result = count;
+
+	if (w1_atoreg_num(dev, buf, count, &rn))
+		return -EINVAL;
+
+	mutex_lock(&md->mutex);
+	sl = w1_slave_search_device(md, &rn);
+	if (sl) {
+		result = w1_slave_detach(sl);
+		/* refcnt 0 means it was detached in the call */
+		if (result == 0)
+			result = count;
+	} else {
+		dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
+			(unsigned long long)rn.id);
+		result = -EINVAL;
+	}
+	mutex_unlock(&md->mutex);
+
+	return result;
+}
+
+#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_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP);
+static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
+static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
+static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO);
+static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
+static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
+static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
+static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
+static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
+
+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_timeout_us.attr,
+	&w1_master_attribute_pointer.attr,
+	&w1_master_attribute_search.attr,
+	&w1_master_attribute_pullup.attr,
+	&w1_master_attribute_add.attr,
+	&w1_master_attribute_remove.attr,
+	NULL
+};
+
+static const 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);
+}
+
+static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct w1_master *md = NULL;
+	struct w1_slave *sl = NULL;
+	char *event_owner, *name;
+	int err = 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 event.\n");
+		return -EINVAL;
+	}
+
+	dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
+			event_owner, name, dev_name(dev));
+
+	if (dev->driver != &w1_slave_driver || !sl)
+		goto end;
+
+	err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
+	if (err)
+		goto end;
+
+	err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
+			     (unsigned long long)sl->reg_num.id);
+end:
+	return err;
+}
+
+static int w1_family_notify(unsigned long action, struct w1_slave *sl)
+{
+	const struct w1_family_ops *fops;
+	int err;
+
+	fops = sl->family->fops;
+
+	if (!fops)
+		return 0;
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		/* if the family driver needs to initialize something... */
+		if (fops->add_slave) {
+			err = fops->add_slave(sl);
+			if (err < 0) {
+				dev_err(&sl->dev,
+					"add_slave() call failed. err=%d\n",
+					err);
+				return err;
+			}
+		}
+		if (fops->groups) {
+			err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
+			if (err) {
+				dev_err(&sl->dev,
+					"sysfs group creation failed. err=%d\n",
+					err);
+				return err;
+			}
+		}
+		if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info) {
+			struct device *hwmon
+				= hwmon_device_register_with_info(&sl->dev,
+						"w1_slave_temp", sl,
+						fops->chip_info,
+						NULL);
+			if (IS_ERR(hwmon)) {
+				dev_warn(&sl->dev,
+					 "could not create hwmon device\n");
+			} else {
+				sl->hwmon = hwmon;
+			}
+		}
+		break;
+	case BUS_NOTIFY_DEL_DEVICE:
+		if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info &&
+			    sl->hwmon)
+			hwmon_device_unregister(sl->hwmon);
+		if (fops->remove_slave)
+			sl->family->fops->remove_slave(sl);
+		if (fops->groups)
+			sysfs_remove_groups(&sl->dev.kobj, fops->groups);
+		break;
+	}
+	return 0;
+}
+
+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;
+	sl->dev.groups = w1_slave_groups;
+	sl->dev.of_node = of_find_matching_node(sl->master->dev.of_node,
+						sl->family->of_match_table);
+
+	dev_set_name(&sl->dev, "%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__,
+		dev_name(&sl->dev), sl);
+
+	/* suppress for w1_family_notify before sending KOBJ_ADD */
+	dev_set_uevent_suppress(&sl->dev, true);
+
+	err = device_register(&sl->dev);
+	if (err < 0) {
+		dev_err(&sl->dev,
+			"Device registration [%s] failed. err=%d\n",
+			dev_name(&sl->dev), err);
+		put_device(&sl->dev);
+		return err;
+	}
+	w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl);
+
+	dev_set_uevent_suppress(&sl->dev, false);
+	kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
+
+	mutex_lock(&sl->master->list_mutex);
+	list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
+	mutex_unlock(&sl->master->list_mutex);
+
+	return 0;
+}
+
+int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
+{
+	struct w1_slave *sl;
+	struct w1_family *f;
+	int err;
+	struct w1_netlink_msg msg;
+
+	sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
+	if (!sl) {
+		dev_err(&dev->dev,
+			 "%s: failed to allocate new slave device.\n",
+			 __func__);
+		return -ENOMEM;
+	}
+
+
+	sl->owner = THIS_MODULE;
+	sl->master = dev;
+	set_bit(W1_SLAVE_ACTIVE, &sl->flags);
+
+	memset(&msg, 0, sizeof(msg));
+	memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
+	atomic_set(&sl->refcnt, 1);
+	atomic_inc(&sl->master->refcnt);
+	dev->slave_count++;
+	dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n",
+		  rn->family, (unsigned long long)rn->id, rn->crc);
+
+	/* slave modules need to be loaded in a context with unlocked mutex */
+	mutex_unlock(&dev->mutex);
+	request_module("w1-family-0x%02X", rn->family);
+	mutex_lock(&dev->mutex);
+
+	spin_lock(&w1_flock);
+	f = w1_family_registered(rn->family);
+	if (!f) {
+		f= &w1_default_family;
+		dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
+			  rn->family, rn->family,
+			  (unsigned long long)rn->id, rn->crc);
+	}
+	__w1_family_get(f);
+	spin_unlock(&w1_flock);
+
+	sl->family = f;
+
+	err = __w1_attach_slave_device(sl);
+	if (err < 0) {
+		dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
+			 sl->name);
+		dev->slave_count--;
+		w1_family_put(sl->family);
+		atomic_dec(&sl->master->refcnt);
+		kfree(sl);
+		return err;
+	}
+
+	sl->ttl = dev->slave_ttl;
+
+	memcpy(msg.id.id, rn, sizeof(msg.id));
+	msg.type = W1_SLAVE_ADD;
+	w1_netlink_send(dev, &msg);
+
+	return 0;
+}
+
+int w1_unref_slave(struct w1_slave *sl)
+{
+	struct w1_master *dev = sl->master;
+	int refcnt;
+	mutex_lock(&dev->list_mutex);
+	refcnt = atomic_sub_return(1, &sl->refcnt);
+	if (refcnt == 0) {
+		struct w1_netlink_msg msg;
+
+		dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
+			sl->name, sl);
+
+		list_del(&sl->w1_slave_entry);
+
+		memset(&msg, 0, sizeof(msg));
+		memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
+		msg.type = W1_SLAVE_REMOVE;
+		w1_netlink_send(sl->master, &msg);
+
+		w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl);
+		device_unregister(&sl->dev);
+		#ifdef DEBUG
+		memset(sl, 0, sizeof(*sl));
+		#endif
+		kfree(sl);
+	}
+	atomic_dec(&dev->refcnt);
+	mutex_unlock(&dev->list_mutex);
+	return refcnt;
+}
+
+int w1_slave_detach(struct w1_slave *sl)
+{
+	/* Only detach a slave once as it decreases the refcnt each time. */
+	int destroy_now;
+	mutex_lock(&sl->master->list_mutex);
+	destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
+	set_bit(W1_SLAVE_DETACH, &sl->flags);
+	mutex_unlock(&sl->master->list_mutex);
+
+	if (destroy_now)
+		destroy_now = !w1_unref_slave(sl);
+	return destroy_now ? 0 : -EBUSY;
+}
+
+struct w1_master *w1_search_master_id(u32 id)
+{
+	struct w1_master *dev;
+	int found = 0;
+
+	mutex_lock(&w1_mlock);
+	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
+		if (dev->id == id) {
+			found = 1;
+			atomic_inc(&dev->refcnt);
+			break;
+		}
+	}
+	mutex_unlock(&w1_mlock);
+
+	return (found)?dev:NULL;
+}
+
+struct w1_slave *w1_search_slave(struct w1_reg_num *id)
+{
+	struct w1_master *dev;
+	struct w1_slave *sl = NULL;
+	int found = 0;
+
+	mutex_lock(&w1_mlock);
+	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
+		mutex_lock(&dev->list_mutex);
+		list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
+			if (sl->reg_num.family == id->family &&
+					sl->reg_num.id == id->id &&
+					sl->reg_num.crc == id->crc) {
+				found = 1;
+				atomic_inc(&dev->refcnt);
+				atomic_inc(&sl->refcnt);
+				break;
+			}
+		}
+		mutex_unlock(&dev->list_mutex);
+
+		if (found)
+			break;
+	}
+	mutex_unlock(&w1_mlock);
+
+	return (found)?sl:NULL;
+}
+
+void w1_reconnect_slaves(struct w1_family *f, int attach)
+{
+	struct w1_slave *sl, *sln;
+	struct w1_master *dev;
+
+	mutex_lock(&w1_mlock);
+	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
+		dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
+			"for family %02x.\n", dev->name, f->fid);
+		mutex_lock(&dev->mutex);
+		mutex_lock(&dev->list_mutex);
+		list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
+			/* If it is a new family, slaves with the default
+			 * family driver and are that family will be
+			 * connected.  If the family is going away, devices
+			 * matching that family are reconneced.
+			 */
+			if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
+				&& sl->reg_num.family == f->fid) ||
+				(!attach && sl->family->fid == f->fid)) {
+				struct w1_reg_num rn;
+
+				mutex_unlock(&dev->list_mutex);
+				memcpy(&rn, &sl->reg_num, sizeof(rn));
+				/* If it was already in use let the automatic
+				 * scan pick it up again later.
+				 */
+				if (!w1_slave_detach(sl))
+					w1_attach_slave_device(dev, &rn);
+				mutex_lock(&dev->list_mutex);
+			}
+		}
+		dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
+			"has been finished.\n", dev->name);
+		mutex_unlock(&dev->list_mutex);
+		mutex_unlock(&dev->mutex);
+	}
+	mutex_unlock(&w1_mlock);
+}
+
+static int w1_addr_crc_is_valid(struct w1_master *dev, u64 rn)
+{
+	u64 rn_le = cpu_to_le64(rn);
+	struct w1_reg_num *tmp = (struct w1_reg_num *)&rn;
+	u8 crc;
+
+	crc = w1_calc_crc8((u8 *)&rn_le, 7);
+
+	/* quirk:
+	 *   DS28E04 (1w eeprom) has strapping pins to change
+	 *   address, but will not update the crc. So normal rules
+	 *   for consistent w1 addresses are violated. We test
+	 *   with the 7 LSBs of the address forced high.
+	 *
+	 *   (char*)&rn_le = { family, addr_lsb, ..., addr_msb, crc }.
+	 */
+	if (crc != tmp->crc && tmp->family == W1_FAMILY_DS28E04) {
+		u64 corr_le = rn_le;
+
+		((u8 *)&corr_le)[1] |= 0x7f;
+		crc = w1_calc_crc8((u8 *)&corr_le, 7);
+
+		dev_info(&dev->dev, "DS28E04 crc workaround on %02x.%012llx.%02x\n",
+			tmp->family, (unsigned long long)tmp->id, tmp->crc);
+	}
+
+	if (crc != tmp->crc) {
+		dev_dbg(&dev->dev, "w1 addr crc mismatch: %02x.%012llx.%02x != 0x%02x.\n",
+			tmp->family, (unsigned long long)tmp->id, tmp->crc, crc);
+		return 0;
+	}
+	return 1;
+}
+
+void w1_slave_found(struct w1_master *dev, u64 rn)
+{
+	struct w1_slave *sl;
+	struct w1_reg_num *tmp;
+
+	atomic_inc(&dev->refcnt);
+
+	tmp = (struct w1_reg_num *) &rn;
+
+	sl = w1_slave_search_device(dev, tmp);
+	if (sl) {
+		set_bit(W1_SLAVE_ACTIVE, &sl->flags);
+	} else {
+		if (rn && w1_addr_crc_is_valid(dev, rn))
+			w1_attach_slave_device(dev, tmp);
+	}
+
+	atomic_dec(&dev->refcnt);
+}
+
+/**
+ * w1_search() - Performs a ROM Search & registers any devices found.
+ * @dev: The master device to search
+ * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH
+ * to return only devices in the alarmed state
+ * @cb: Function to call when a device is found
+ *
+ * The 1-wire search is a simple binary tree search.
+ * For each bit of the address, we read two bits and write one bit.
+ * The bit written will put to sleep all devies that don't match that bit.
+ * When the two reads differ, the direction choice is obvious.
+ * When both bits are 0, we must choose a path to take.
+ * When we can scan all 64 bits without having to choose a path, we are done.
+ *
+ * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
+ *
+ */
+void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
+{
+	u64 last_rn, rn, tmp64;
+	int i, slave_count = 0;
+	int last_zero, last_device;
+	int search_bit, desc_bit;
+	u8  triplet_ret = 0;
+
+	search_bit = 0;
+	rn = dev->search_id;
+	last_rn = 0;
+	last_device = 0;
+	last_zero = -1;
+
+	desc_bit = 64;
+
+	while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
+		last_rn = rn;
+		rn = 0;
+
+		/*
+		 * Reset bus and all 1-wire device state machines
+		 * so they can respond to our requests.
+		 *
+		 * Return 0 - device(s) present, 1 - no devices present.
+		 */
+		mutex_lock(&dev->bus_mutex);
+		if (w1_reset_bus(dev)) {
+			mutex_unlock(&dev->bus_mutex);
+			dev_dbg(&dev->dev, "No devices present on the wire.\n");
+			break;
+		}
+
+		/* Do fast search on single slave bus */
+		if (dev->max_slave_count == 1) {
+			int rv;
+			w1_write_8(dev, W1_READ_ROM);
+			rv = w1_read_block(dev, (u8 *)&rn, 8);
+			mutex_unlock(&dev->bus_mutex);
+
+			if (rv == 8 && rn)
+				cb(dev, rn);
+
+			break;
+		}
+
+		/* Start the search */
+		w1_write_8(dev, search_type);
+		for (i = 0; i < 64; ++i) {
+			/* Determine the direction/search bit */
+			if (i == desc_bit)
+				search_bit = 1;	  /* took the 0 path last time, so take the 1 path */
+			else if (i > desc_bit)
+				search_bit = 0;	  /* take the 0 path on the next branch */
+			else
+				search_bit = ((last_rn >> i) & 0x1);
+
+			/* Read two bits and write one bit */
+			triplet_ret = w1_triplet(dev, search_bit);
+
+			/* quit if no device responded */
+			if ( (triplet_ret & 0x03) == 0x03 )
+				break;
+
+			/* If both directions were valid, and we took the 0 path... */
+			if (triplet_ret == 0)
+				last_zero = i;
+
+			/* extract the direction taken & update the device number */
+			tmp64 = (triplet_ret >> 2);
+			rn |= (tmp64 << i);
+
+			if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {
+				mutex_unlock(&dev->bus_mutex);
+				dev_dbg(&dev->dev, "Abort w1_search\n");
+				return;
+			}
+		}
+		mutex_unlock(&dev->bus_mutex);
+
+		if ( (triplet_ret & 0x03) != 0x03 ) {
+			if ((desc_bit == last_zero) || (last_zero < 0)) {
+				last_device = 1;
+				dev->search_id = 0;
+			} else {
+				dev->search_id = rn;
+			}
+			desc_bit = last_zero;
+			cb(dev, rn);
+		}
+
+		if (!last_device && slave_count == dev->max_slave_count &&
+			!test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {
+			/* Only max_slave_count will be scanned in a search,
+			 * but it will start where it left off next search
+			 * until all ids are identified and then it will start
+			 * over.  A continued search will report the previous
+			 * last id as the first id (provided it is still on the
+			 * bus).
+			 */
+			dev_info(&dev->dev, "%s: max_slave_count %d reached, "
+				"will continue next search.\n", __func__,
+				dev->max_slave_count);
+			set_bit(W1_WARN_MAX_COUNT, &dev->flags);
+		}
+	}
+}
+
+void w1_search_process_cb(struct w1_master *dev, u8 search_type,
+	w1_slave_found_callback cb)
+{
+	struct w1_slave *sl, *sln;
+
+	mutex_lock(&dev->list_mutex);
+	list_for_each_entry(sl, &dev->slist, w1_slave_entry)
+		clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
+	mutex_unlock(&dev->list_mutex);
+
+	w1_search_devices(dev, search_type, cb);
+
+	mutex_lock(&dev->list_mutex);
+	list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
+		if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
+			mutex_unlock(&dev->list_mutex);
+			w1_slave_detach(sl);
+			mutex_lock(&dev->list_mutex);
+		}
+		else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
+			sl->ttl = dev->slave_ttl;
+	}
+	mutex_unlock(&dev->list_mutex);
+
+	if (dev->search_count > 0)
+		dev->search_count--;
+}
+
+static void w1_search_process(struct w1_master *dev, u8 search_type)
+{
+	w1_search_process_cb(dev, search_type, w1_slave_found);
+}
+
+/**
+ * w1_process_callbacks() - execute each dev->async_list callback entry
+ * @dev: w1_master device
+ *
+ * The w1 master list_mutex must be held.
+ *
+ * Return: 1 if there were commands to executed 0 otherwise
+ */
+int w1_process_callbacks(struct w1_master *dev)
+{
+	int ret = 0;
+	struct w1_async_cmd *async_cmd, *async_n;
+
+	/* The list can be added to in another thread, loop until it is empty */
+	while (!list_empty(&dev->async_list)) {
+		list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
+			async_entry) {
+			/* drop the lock, if it is a search it can take a long
+			 * time */
+			mutex_unlock(&dev->list_mutex);
+			async_cmd->cb(dev, async_cmd);
+			ret = 1;
+			mutex_lock(&dev->list_mutex);
+		}
+	}
+	return ret;
+}
+
+int w1_process(void *data)
+{
+	struct w1_master *dev = (struct w1_master *) data;
+	/* As long as w1_timeout is only set by a module parameter the sleep
+	 * time can be calculated in jiffies once.
+	 */
+	const unsigned long jtime =
+	  usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us);
+	/* remainder if it woke up early */
+	unsigned long jremain = 0;
+
+	atomic_inc(&dev->refcnt);
+
+	for (;;) {
+
+		if (!jremain && dev->search_count) {
+			mutex_lock(&dev->mutex);
+			w1_search_process(dev, W1_SEARCH);
+			mutex_unlock(&dev->mutex);
+		}
+
+		mutex_lock(&dev->list_mutex);
+		/* Note, w1_process_callback drops the lock while processing,
+		 * but locks it again before returning.
+		 */
+		if (!w1_process_callbacks(dev) && jremain) {
+			/* a wake up is either to stop the thread, process
+			 * callbacks, or search, it isn't process callbacks, so
+			 * schedule a search.
+			 */
+			jremain = 1;
+		}
+
+		__set_current_state(TASK_INTERRUPTIBLE);
+
+		/* hold list_mutex until after interruptible to prevent loosing
+		 * the wakeup signal when async_cmd is added.
+		 */
+		mutex_unlock(&dev->list_mutex);
+
+		if (kthread_should_stop()) {
+			__set_current_state(TASK_RUNNING);
+			break;
+		}
+
+		/* Only sleep when the search is active. */
+		if (dev->search_count) {
+			if (!jremain)
+				jremain = jtime;
+			jremain = schedule_timeout(jremain);
+		}
+		else
+			schedule();
+	}
+
+	atomic_dec(&dev->refcnt);
+
+	return 0;
+}
+
+static int __init w1_init(void)
+{
+	int retval;
+
+	pr_info("Driver for 1-wire Dallas network protocol.\n");
+
+	w1_init_netlink();
+
+	retval = bus_register(&w1_bus_type);
+	if (retval) {
+		pr_err("Failed to register bus. err=%d.\n", retval);
+		goto err_out_exit_init;
+	}
+
+	retval = driver_register(&w1_master_driver);
+	if (retval) {
+		pr_err("Failed to register master driver. err=%d.\n",
+			retval);
+		goto err_out_bus_unregister;
+	}
+
+	retval = driver_register(&w1_slave_driver);
+	if (retval) {
+		pr_err("Failed to register slave driver. err=%d.\n",
+			retval);
+		goto err_out_master_unregister;
+	}
+
+	return 0;
+
+#if 0
+/* For undoing the slave register if there was a step after it. */
+err_out_slave_unregister:
+	driver_unregister(&w1_slave_driver);
+#endif
+
+err_out_master_unregister:
+	driver_unregister(&w1_master_driver);
+
+err_out_bus_unregister:
+	bus_unregister(&w1_bus_type);
+
+err_out_exit_init:
+	return retval;
+}
+
+static void __exit w1_fini(void)
+{
+	struct w1_master *dev, *n;
+
+	/* Set netlink removal messages and some cleanup */
+	list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry)
+		__w1_remove_master_device(dev);
+
+	w1_fini_netlink();
+
+	driver_unregister(&w1_slave_driver);
+	driver_unregister(&w1_master_driver);
+	bus_unregister(&w1_bus_type);
+}
+
+module_init(w1_init);
+module_exit(w1_fini);
+
+MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
+MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
+MODULE_LICENSE("GPL");