IIO: Move the core files to drivers/iio

Take the core support + the kfifo buffer implentation out of
staging.  Whilst we are far from done in improving this subsystem
it is now at a stage where the userspae interfaces (provided by
the core) can be considered stable.

Drivers will follow over a longer time scale.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 912 insertions, 0 deletions

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
new file mode 100644
index 000000000000..dd1a6a2e81c0
--- /dev/null
+++ b/drivers/iio/industrialio-core.c
@@ -0,0 +1,912 @@
+/* The industrial I/O core
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * Based on elements of hwmon and input subsystems.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/idr.h>
+#include <linux/kdev_t.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/anon_inodes.h>
+#include <linux/debugfs.h>
+#include <linux/iio/iio.h>
+#include "iio_core.h"
+#include "iio_core_trigger.h"
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+/* IDA to assign each registered device a unique id*/
+static DEFINE_IDA(iio_ida);
+
+static dev_t iio_devt;
+
+#define IIO_DEV_MAX 256
+struct bus_type iio_bus_type = {
+	.name = "iio",
+};
+EXPORT_SYMBOL(iio_bus_type);
+
+static struct dentry *iio_debugfs_dentry;
+
+static const char * const iio_direction[] = {
+	[0] = "in",
+	[1] = "out",
+};
+
+static const char * const iio_chan_type_name_spec[] = {
+	[IIO_VOLTAGE] = "voltage",
+	[IIO_CURRENT] = "current",
+	[IIO_POWER] = "power",
+	[IIO_ACCEL] = "accel",
+	[IIO_ANGL_VEL] = "anglvel",
+	[IIO_MAGN] = "magn",
+	[IIO_LIGHT] = "illuminance",
+	[IIO_INTENSITY] = "intensity",
+	[IIO_PROXIMITY] = "proximity",
+	[IIO_TEMP] = "temp",
+	[IIO_INCLI] = "incli",
+	[IIO_ROT] = "rot",
+	[IIO_ANGL] = "angl",
+	[IIO_TIMESTAMP] = "timestamp",
+	[IIO_CAPACITANCE] = "capacitance",
+};
+
+static const char * const iio_modifier_names[] = {
+	[IIO_MOD_X] = "x",
+	[IIO_MOD_Y] = "y",
+	[IIO_MOD_Z] = "z",
+	[IIO_MOD_LIGHT_BOTH] = "both",
+	[IIO_MOD_LIGHT_IR] = "ir",
+};
+
+/* relies on pairs of these shared then separate */
+static const char * const iio_chan_info_postfix[] = {
+	[IIO_CHAN_INFO_RAW] = "raw",
+	[IIO_CHAN_INFO_PROCESSED] = "input",
+	[IIO_CHAN_INFO_SCALE] = "scale",
+	[IIO_CHAN_INFO_OFFSET] = "offset",
+	[IIO_CHAN_INFO_CALIBSCALE] = "calibscale",
+	[IIO_CHAN_INFO_CALIBBIAS] = "calibbias",
+	[IIO_CHAN_INFO_PEAK] = "peak_raw",
+	[IIO_CHAN_INFO_PEAK_SCALE] = "peak_scale",
+	[IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW] = "quadrature_correction_raw",
+	[IIO_CHAN_INFO_AVERAGE_RAW] = "mean_raw",
+	[IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY]
+	= "filter_low_pass_3db_frequency",
+	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
+};
+
+const struct iio_chan_spec
+*iio_find_channel_from_si(struct iio_dev *indio_dev, int si)
+{
+	int i;
+
+	for (i = 0; i < indio_dev->num_channels; i++)
+		if (indio_dev->channels[i].scan_index == si)
+			return &indio_dev->channels[i];
+	return NULL;
+}
+
+/* This turns up an awful lot */
+ssize_t iio_read_const_attr(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
+}
+EXPORT_SYMBOL(iio_read_const_attr);
+
+static int __init iio_init(void)
+{
+	int ret;
+
+	/* Register sysfs bus */
+	ret  = bus_register(&iio_bus_type);
+	if (ret < 0) {
+		printk(KERN_ERR
+		       "%s could not register bus type\n",
+			__FILE__);
+		goto error_nothing;
+	}
+
+	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
+	if (ret < 0) {
+		printk(KERN_ERR "%s: failed to allocate char dev region\n",
+		       __FILE__);
+		goto error_unregister_bus_type;
+	}
+
+	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
+
+	return 0;
+
+error_unregister_bus_type:
+	bus_unregister(&iio_bus_type);
+error_nothing:
+	return ret;
+}
+
+static void __exit iio_exit(void)
+{
+	if (iio_devt)
+		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
+	bus_unregister(&iio_bus_type);
+	debugfs_remove(iio_debugfs_dentry);
+}
+
+#if defined(CONFIG_DEBUG_FS)
+static int iio_debugfs_open(struct inode *inode, struct file *file)
+{
+	if (inode->i_private)
+		file->private_data = inode->i_private;
+
+	return 0;
+}
+
+static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
+			      size_t count, loff_t *ppos)
+{
+	struct iio_dev *indio_dev = file->private_data;
+	char buf[20];
+	unsigned val = 0;
+	ssize_t len;
+	int ret;
+
+	ret = indio_dev->info->debugfs_reg_access(indio_dev,
+						  indio_dev->cached_reg_addr,
+						  0, &val);
+	if (ret)
+		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
+
+	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
+}
+
+static ssize_t iio_debugfs_write_reg(struct file *file,
+		     const char __user *userbuf, size_t count, loff_t *ppos)
+{
+	struct iio_dev *indio_dev = file->private_data;
+	unsigned reg, val;
+	char buf[80];
+	int ret;
+
+	count = min_t(size_t, count, (sizeof(buf)-1));
+	if (copy_from_user(buf, userbuf, count))
+		return -EFAULT;
+
+	buf[count] = 0;
+
+	ret = sscanf(buf, "%i %i", &reg, &val);
+
+	switch (ret) {
+	case 1:
+		indio_dev->cached_reg_addr = reg;
+		break;
+	case 2:
+		indio_dev->cached_reg_addr = reg;
+		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
+							  val, NULL);
+		if (ret) {
+			dev_err(indio_dev->dev.parent, "%s: write failed\n",
+				__func__);
+			return ret;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return count;
+}
+
+static const struct file_operations iio_debugfs_reg_fops = {
+	.open = iio_debugfs_open,
+	.read = iio_debugfs_read_reg,
+	.write = iio_debugfs_write_reg,
+};
+
+static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
+{
+	debugfs_remove_recursive(indio_dev->debugfs_dentry);
+}
+
+static int iio_device_register_debugfs(struct iio_dev *indio_dev)
+{
+	struct dentry *d;
+
+	if (indio_dev->info->debugfs_reg_access == NULL)
+		return 0;
+
+	if (IS_ERR(iio_debugfs_dentry))
+		return 0;
+
+	indio_dev->debugfs_dentry =
+		debugfs_create_dir(dev_name(&indio_dev->dev),
+				   iio_debugfs_dentry);
+	if (IS_ERR(indio_dev->debugfs_dentry))
+		return PTR_ERR(indio_dev->debugfs_dentry);
+
+	if (indio_dev->debugfs_dentry == NULL) {
+		dev_warn(indio_dev->dev.parent,
+			 "Failed to create debugfs directory\n");
+		return -EFAULT;
+	}
+
+	d = debugfs_create_file("direct_reg_access", 0644,
+				indio_dev->debugfs_dentry,
+				indio_dev, &iio_debugfs_reg_fops);
+	if (!d) {
+		iio_device_unregister_debugfs(indio_dev);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+#else
+static int iio_device_register_debugfs(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
+static ssize_t iio_read_channel_ext_info(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	const struct iio_chan_spec_ext_info *ext_info;
+
+	ext_info = &this_attr->c->ext_info[this_attr->address];
+
+	return ext_info->read(indio_dev, this_attr->c, buf);
+}
+
+static ssize_t iio_write_channel_ext_info(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf,
+					 size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	const struct iio_chan_spec_ext_info *ext_info;
+
+	ext_info = &this_attr->c->ext_info[this_attr->address];
+
+	return ext_info->write(indio_dev, this_attr->c, buf, len);
+}
+
+static ssize_t iio_read_channel_info(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int val, val2;
+	int ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
+					    &val, &val2, this_attr->address);
+
+	if (ret < 0)
+		return ret;
+
+	if (ret == IIO_VAL_INT)
+		return sprintf(buf, "%d\n", val);
+	else if (ret == IIO_VAL_INT_PLUS_MICRO) {
+		if (val2 < 0)
+			return sprintf(buf, "-%d.%06u\n", val, -val2);
+		else
+			return sprintf(buf, "%d.%06u\n", val, val2);
+	} else if (ret == IIO_VAL_INT_PLUS_NANO) {
+		if (val2 < 0)
+			return sprintf(buf, "-%d.%09u\n", val, -val2);
+		else
+			return sprintf(buf, "%d.%09u\n", val, val2);
+	} else
+		return 0;
+}
+
+static ssize_t iio_write_channel_info(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf,
+				      size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int ret, integer = 0, fract = 0, fract_mult = 100000;
+	bool integer_part = true, negative = false;
+
+	/* Assumes decimal - precision based on number of digits */
+	if (!indio_dev->info->write_raw)
+		return -EINVAL;
+
+	if (indio_dev->info->write_raw_get_fmt)
+		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
+			this_attr->c, this_attr->address)) {
+		case IIO_VAL_INT_PLUS_MICRO:
+			fract_mult = 100000;
+			break;
+		case IIO_VAL_INT_PLUS_NANO:
+			fract_mult = 100000000;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+	if (buf[0] == '-') {
+		negative = true;
+		buf++;
+	}
+
+	while (*buf) {
+		if ('0' <= *buf && *buf <= '9') {
+			if (integer_part)
+				integer = integer*10 + *buf - '0';
+			else {
+				fract += fract_mult*(*buf - '0');
+				if (fract_mult == 1)
+					break;
+				fract_mult /= 10;
+			}
+		} else if (*buf == '\n') {
+			if (*(buf + 1) == '\0')
+				break;
+			else
+				return -EINVAL;
+		} else if (*buf == '.') {
+			integer_part = false;
+		} else {
+			return -EINVAL;
+		}
+		buf++;
+	}
+	if (negative) {
+		if (integer)
+			integer = -integer;
+		else
+			fract = -fract;
+	}
+
+	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
+					 integer, fract, this_attr->address);
+	if (ret)
+		return ret;
+
+	return len;
+}
+
+static
+int __iio_device_attr_init(struct device_attribute *dev_attr,
+			   const char *postfix,
+			   struct iio_chan_spec const *chan,
+			   ssize_t (*readfunc)(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf),
+			   ssize_t (*writefunc)(struct device *dev,
+						struct device_attribute *attr,
+						const char *buf,
+						size_t len),
+			   bool generic)
+{
+	int ret;
+	char *name_format, *full_postfix;
+	sysfs_attr_init(&dev_attr->attr);
+
+	/* Build up postfix of <extend_name>_<modifier>_postfix */
+	if (chan->modified && !generic) {
+		if (chan->extend_name)
+			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
+						 iio_modifier_names[chan
+								    ->channel2],
+						 chan->extend_name,
+						 postfix);
+		else
+			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
+						 iio_modifier_names[chan
+								    ->channel2],
+						 postfix);
+	} else {
+		if (chan->extend_name == NULL)
+			full_postfix = kstrdup(postfix, GFP_KERNEL);
+		else
+			full_postfix = kasprintf(GFP_KERNEL,
+						 "%s_%s",
+						 chan->extend_name,
+						 postfix);
+	}
+	if (full_postfix == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	if (chan->differential) { /* Differential can not have modifier */
+		if (generic)
+			name_format
+				= kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
+					    iio_direction[chan->output],
+					    iio_chan_type_name_spec[chan->type],
+					    iio_chan_type_name_spec[chan->type],
+					    full_postfix);
+		else if (chan->indexed)
+			name_format
+				= kasprintf(GFP_KERNEL, "%s_%s%d-%s%d_%s",
+					    iio_direction[chan->output],
+					    iio_chan_type_name_spec[chan->type],
+					    chan->channel,
+					    iio_chan_type_name_spec[chan->type],
+					    chan->channel2,
+					    full_postfix);
+		else {
+			WARN_ON("Differential channels must be indexed\n");
+			ret = -EINVAL;
+			goto error_free_full_postfix;
+		}
+	} else { /* Single ended */
+		if (generic)
+			name_format
+				= kasprintf(GFP_KERNEL, "%s_%s_%s",
+					    iio_direction[chan->output],
+					    iio_chan_type_name_spec[chan->type],
+					    full_postfix);
+		else if (chan->indexed)
+			name_format
+				= kasprintf(GFP_KERNEL, "%s_%s%d_%s",
+					    iio_direction[chan->output],
+					    iio_chan_type_name_spec[chan->type],
+					    chan->channel,
+					    full_postfix);
+		else
+			name_format
+				= kasprintf(GFP_KERNEL, "%s_%s_%s",
+					    iio_direction[chan->output],
+					    iio_chan_type_name_spec[chan->type],
+					    full_postfix);
+	}
+	if (name_format == NULL) {
+		ret = -ENOMEM;
+		goto error_free_full_postfix;
+	}
+	dev_attr->attr.name = kasprintf(GFP_KERNEL,
+					name_format,
+					chan->channel,
+					chan->channel2);
+	if (dev_attr->attr.name == NULL) {
+		ret = -ENOMEM;
+		goto error_free_name_format;
+	}
+
+	if (readfunc) {
+		dev_attr->attr.mode |= S_IRUGO;
+		dev_attr->show = readfunc;
+	}
+
+	if (writefunc) {
+		dev_attr->attr.mode |= S_IWUSR;
+		dev_attr->store = writefunc;
+	}
+	kfree(name_format);
+	kfree(full_postfix);
+
+	return 0;
+
+error_free_name_format:
+	kfree(name_format);
+error_free_full_postfix:
+	kfree(full_postfix);
+error_ret:
+	return ret;
+}
+
+static void __iio_device_attr_deinit(struct device_attribute *dev_attr)
+{
+	kfree(dev_attr->attr.name);
+}
+
+int __iio_add_chan_devattr(const char *postfix,
+			   struct iio_chan_spec const *chan,
+			   ssize_t (*readfunc)(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf),
+			   ssize_t (*writefunc)(struct device *dev,
+						struct device_attribute *attr,
+						const char *buf,
+						size_t len),
+			   u64 mask,
+			   bool generic,
+			   struct device *dev,
+			   struct list_head *attr_list)
+{
+	int ret;
+	struct iio_dev_attr *iio_attr, *t;
+
+	iio_attr = kzalloc(sizeof *iio_attr, GFP_KERNEL);
+	if (iio_attr == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+	ret = __iio_device_attr_init(&iio_attr->dev_attr,
+				     postfix, chan,
+				     readfunc, writefunc, generic);
+	if (ret)
+		goto error_iio_dev_attr_free;
+	iio_attr->c = chan;
+	iio_attr->address = mask;
+	list_for_each_entry(t, attr_list, l)
+		if (strcmp(t->dev_attr.attr.name,
+			   iio_attr->dev_attr.attr.name) == 0) {
+			if (!generic)
+				dev_err(dev, "tried to double register : %s\n",
+					t->dev_attr.attr.name);
+			ret = -EBUSY;
+			goto error_device_attr_deinit;
+		}
+	list_add(&iio_attr->l, attr_list);
+
+	return 0;
+
+error_device_attr_deinit:
+	__iio_device_attr_deinit(&iio_attr->dev_attr);
+error_iio_dev_attr_free:
+	kfree(iio_attr);
+error_ret:
+	return ret;
+}
+
+static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
+					struct iio_chan_spec const *chan)
+{
+	int ret, attrcount = 0;
+	int i;
+	const struct iio_chan_spec_ext_info *ext_info;
+
+	if (chan->channel < 0)
+		return 0;
+	for_each_set_bit(i, &chan->info_mask, sizeof(long)*8) {
+		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i/2],
+					     chan,
+					     &iio_read_channel_info,
+					     &iio_write_channel_info,
+					     i/2,
+					     !(i%2),
+					     &indio_dev->dev,
+					     &indio_dev->channel_attr_list);
+		if (ret == -EBUSY && (i%2 == 0)) {
+			ret = 0;
+			continue;
+		}
+		if (ret < 0)
+			goto error_ret;
+		attrcount++;
+	}
+
+	if (chan->ext_info) {
+		unsigned int i = 0;
+		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
+			ret = __iio_add_chan_devattr(ext_info->name,
+					chan,
+					ext_info->read ?
+					    &iio_read_channel_ext_info : NULL,
+					ext_info->write ?
+					    &iio_write_channel_ext_info : NULL,
+					i,
+					ext_info->shared,
+					&indio_dev->dev,
+					&indio_dev->channel_attr_list);
+			i++;
+			if (ret == -EBUSY && ext_info->shared)
+				continue;
+
+			if (ret)
+				goto error_ret;
+
+			attrcount++;
+		}
+	}
+
+	ret = attrcount;
+error_ret:
+	return ret;
+}
+
+static void iio_device_remove_and_free_read_attr(struct iio_dev *indio_dev,
+						 struct iio_dev_attr *p)
+{
+	kfree(p->dev_attr.attr.name);
+	kfree(p);
+}
+
+static ssize_t iio_show_dev_name(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	return sprintf(buf, "%s\n", indio_dev->name);
+}
+
+static DEVICE_ATTR(name, S_IRUGO, iio_show_dev_name, NULL);
+
+static int iio_device_register_sysfs(struct iio_dev *indio_dev)
+{
+	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
+	struct iio_dev_attr *p, *n;
+	struct attribute **attr;
+
+	/* First count elements in any existing group */
+	if (indio_dev->info->attrs) {
+		attr = indio_dev->info->attrs->attrs;
+		while (*attr++ != NULL)
+			attrcount_orig++;
+	}
+	attrcount = attrcount_orig;
+	/*
+	 * New channel registration method - relies on the fact a group does
+	 * not need to be initialized if it is name is NULL.
+	 */
+	INIT_LIST_HEAD(&indio_dev->channel_attr_list);
+	if (indio_dev->channels)
+		for (i = 0; i < indio_dev->num_channels; i++) {
+			ret = iio_device_add_channel_sysfs(indio_dev,
+							   &indio_dev
+							   ->channels[i]);
+			if (ret < 0)
+				goto error_clear_attrs;
+			attrcount += ret;
+		}
+
+	if (indio_dev->name)
+		attrcount++;
+
+	indio_dev->chan_attr_group.attrs = kcalloc(attrcount + 1,
+						   sizeof(indio_dev->chan_attr_group.attrs[0]),
+						   GFP_KERNEL);
+	if (indio_dev->chan_attr_group.attrs == NULL) {
+		ret = -ENOMEM;
+		goto error_clear_attrs;
+	}
+	/* Copy across original attributes */
+	if (indio_dev->info->attrs)
+		memcpy(indio_dev->chan_attr_group.attrs,
+		       indio_dev->info->attrs->attrs,
+		       sizeof(indio_dev->chan_attr_group.attrs[0])
+		       *attrcount_orig);
+	attrn = attrcount_orig;
+	/* Add all elements from the list. */
+	list_for_each_entry(p, &indio_dev->channel_attr_list, l)
+		indio_dev->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
+	if (indio_dev->name)
+		indio_dev->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
+
+	indio_dev->groups[indio_dev->groupcounter++] =
+		&indio_dev->chan_attr_group;
+
+	return 0;
+
+error_clear_attrs:
+	list_for_each_entry_safe(p, n,
+				 &indio_dev->channel_attr_list, l) {
+		list_del(&p->l);
+		iio_device_remove_and_free_read_attr(indio_dev, p);
+	}
+
+	return ret;
+}
+
+static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
+{
+
+	struct iio_dev_attr *p, *n;
+
+	list_for_each_entry_safe(p, n, &indio_dev->channel_attr_list, l) {
+		list_del(&p->l);
+		iio_device_remove_and_free_read_attr(indio_dev, p);
+	}
+	kfree(indio_dev->chan_attr_group.attrs);
+}
+
+static void iio_dev_release(struct device *device)
+{
+	struct iio_dev *indio_dev = container_of(device, struct iio_dev, dev);
+	cdev_del(&indio_dev->chrdev);
+	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
+		iio_device_unregister_trigger_consumer(indio_dev);
+	iio_device_unregister_eventset(indio_dev);
+	iio_device_unregister_sysfs(indio_dev);
+	iio_device_unregister_debugfs(indio_dev);
+}
+
+static struct device_type iio_dev_type = {
+	.name = "iio_device",
+	.release = iio_dev_release,
+};
+
+struct iio_dev *iio_allocate_device(int sizeof_priv)
+{
+	struct iio_dev *dev;
+	size_t alloc_size;
+
+	alloc_size = sizeof(struct iio_dev);
+	if (sizeof_priv) {
+		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
+		alloc_size += sizeof_priv;
+	}
+	/* ensure 32-byte alignment of whole construct ? */
+	alloc_size += IIO_ALIGN - 1;
+
+	dev = kzalloc(alloc_size, GFP_KERNEL);
+
+	if (dev) {
+		dev->dev.groups = dev->groups;
+		dev->dev.type = &iio_dev_type;
+		dev->dev.bus = &iio_bus_type;
+		device_initialize(&dev->dev);
+		dev_set_drvdata(&dev->dev, (void *)dev);
+		mutex_init(&dev->mlock);
+		mutex_init(&dev->info_exist_lock);
+
+		dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
+		if (dev->id < 0) {
+			/* cannot use a dev_err as the name isn't available */
+			printk(KERN_ERR "Failed to get id\n");
+			kfree(dev);
+			return NULL;
+		}
+		dev_set_name(&dev->dev, "iio:device%d", dev->id);
+	}
+
+	return dev;
+}
+EXPORT_SYMBOL(iio_allocate_device);
+
+void iio_free_device(struct iio_dev *dev)
+{
+	if (dev) {
+		ida_simple_remove(&iio_ida, dev->id);
+		kfree(dev);
+	}
+}
+EXPORT_SYMBOL(iio_free_device);
+
+/**
+ * iio_chrdev_open() - chrdev file open for buffer access and ioctls
+ **/
+static int iio_chrdev_open(struct inode *inode, struct file *filp)
+{
+	struct iio_dev *indio_dev = container_of(inode->i_cdev,
+						struct iio_dev, chrdev);
+
+	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
+		return -EBUSY;
+
+	filp->private_data = indio_dev;
+
+	return 0;
+}
+
+/**
+ * iio_chrdev_release() - chrdev file close buffer access and ioctls
+ **/
+static int iio_chrdev_release(struct inode *inode, struct file *filp)
+{
+	struct iio_dev *indio_dev = container_of(inode->i_cdev,
+						struct iio_dev, chrdev);
+	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
+	return 0;
+}
+
+/* Somewhat of a cross file organization violation - ioctls here are actually
+ * event related */
+static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct iio_dev *indio_dev = filp->private_data;
+	int __user *ip = (int __user *)arg;
+	int fd;
+
+	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
+		fd = iio_event_getfd(indio_dev);
+		if (copy_to_user(ip, &fd, sizeof(fd)))
+			return -EFAULT;
+		return 0;
+	}
+	return -EINVAL;
+}
+
+static const struct file_operations iio_buffer_fileops = {
+	.read = iio_buffer_read_first_n_outer_addr,
+	.release = iio_chrdev_release,
+	.open = iio_chrdev_open,
+	.poll = iio_buffer_poll_addr,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = iio_ioctl,
+	.compat_ioctl = iio_ioctl,
+};
+
+static const struct iio_buffer_setup_ops noop_ring_setup_ops;
+
+int iio_device_register(struct iio_dev *indio_dev)
+{
+	int ret;
+
+	/* configure elements for the chrdev */
+	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
+
+	ret = iio_device_register_debugfs(indio_dev);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"Failed to register debugfs interfaces\n");
+		goto error_ret;
+	}
+	ret = iio_device_register_sysfs(indio_dev);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"Failed to register sysfs interfaces\n");
+		goto error_unreg_debugfs;
+	}
+	ret = iio_device_register_eventset(indio_dev);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"Failed to register event set\n");
+		goto error_free_sysfs;
+	}
+	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
+		iio_device_register_trigger_consumer(indio_dev);
+
+	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
+		indio_dev->setup_ops == NULL)
+		indio_dev->setup_ops = &noop_ring_setup_ops;
+
+	ret = device_add(&indio_dev->dev);
+	if (ret < 0)
+		goto error_unreg_eventset;
+	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
+	indio_dev->chrdev.owner = indio_dev->info->driver_module;
+	ret = cdev_add(&indio_dev->chrdev, indio_dev->dev.devt, 1);
+	if (ret < 0)
+		goto error_del_device;
+	return 0;
+
+error_del_device:
+	device_del(&indio_dev->dev);
+error_unreg_eventset:
+	iio_device_unregister_eventset(indio_dev);
+error_free_sysfs:
+	iio_device_unregister_sysfs(indio_dev);
+error_unreg_debugfs:
+	iio_device_unregister_debugfs(indio_dev);
+error_ret:
+	return ret;
+}
+EXPORT_SYMBOL(iio_device_register);
+
+void iio_device_unregister(struct iio_dev *indio_dev)
+{
+	mutex_lock(&indio_dev->info_exist_lock);
+	indio_dev->info = NULL;
+	mutex_unlock(&indio_dev->info_exist_lock);
+	device_unregister(&indio_dev->dev);
+}
+EXPORT_SYMBOL(iio_device_unregister);
+subsys_initcall(iio_init);
+module_exit(iio_exit);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
+MODULE_DESCRIPTION("Industrial I/O core");
+MODULE_LICENSE("GPL");