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>

10 files changed, 3240 insertions, 0 deletions

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
new file mode 100644
index 00000000000..3ab7d48d0b0
--- /dev/null
+++ b/drivers/iio/Kconfig
@@ -0,0 +1,51 @@
+#
+# Industrial I/O subsytem configuration
+#
+
+menuconfig IIO
+	tristate "Industrial I/O support"
+	depends on GENERIC_HARDIRQS
+	help
+	  The industrial I/O subsystem provides a unified framework for
+	  drivers for many different types of embedded sensors using a
+	  number of different physical interfaces (i2c, spi, etc). See
+	  Documentation/iio for more information.
+
+if IIO
+
+config IIO_BUFFER
+	bool "Enable buffer support within IIO"
+	help
+	  Provide core support for various buffer based data
+	  acquisition methods.
+
+if IIO_BUFFER
+
+config IIO_KFIFO_BUF
+	select IIO_TRIGGER
+	tristate "Industrial I/O buffering based on kfifo"
+	help
+	  A simple fifo based on kfifo.  Use this if you want a fifo
+	  rather than a ring buffer. Note that this currently provides
+	  no buffer events so it is up to userspace to work out how
+	  often to read from the buffer.
+
+endif # IIO_BUFFER
+
+config IIO_TRIGGER
+	boolean "Enable triggered sampling support"
+	help
+	  Provides IIO core support for triggers.  Currently these
+	  are used to initialize capture of samples to push into
+	  ring buffers.  The triggers are effectively a 'capture
+	  data now' interrupt.
+
+config IIO_CONSUMERS_PER_TRIGGER
+       int "Maximum number of consumers per trigger"
+       depends on IIO_TRIGGER
+       default "2"
+       help
+	This value controls the maximum number of consumers that a
+	given trigger may handle. Default is 2.
+
+endif # IIO
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
new file mode 100644
index 00000000000..d5fc57d12ea
--- /dev/null
+++ b/drivers/iio/Makefile
@@ -0,0 +1,10 @@
+#
+# Makefile for the industrial I/O core.
+#
+
+obj-$(CONFIG_IIO) += industrialio.o
+industrialio-y := industrialio-core.o industrialio-event.o inkern.o
+industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
+industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
+
+obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
new file mode 100644
index 00000000000..f652e6ae5a3
--- /dev/null
+++ b/drivers/iio/iio_core.h
@@ -0,0 +1,62 @@
+/* The industrial I/O core function defs.
+ *
+ * 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.
+ *
+ * These definitions are meant for use only within the IIO core, not individual
+ * drivers.
+ */
+
+#ifndef _IIO_CORE_H_
+#define _IIO_CORE_H_
+#include <linux/kernel.h>
+#include <linux/device.h>
+
+struct iio_chan_spec;
+struct iio_dev;
+
+
+int __iio_add_chan_devattr(const char *postfix,
+			   struct iio_chan_spec const *chan,
+			   ssize_t (*func)(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);
+
+/* Event interface flags */
+#define IIO_BUSY_BIT_POS 1
+
+#ifdef CONFIG_IIO_BUFFER
+struct poll_table_struct;
+
+unsigned int iio_buffer_poll(struct file *filp,
+			     struct poll_table_struct *wait);
+ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
+				      size_t n, loff_t *f_ps);
+
+
+#define iio_buffer_poll_addr (&iio_buffer_poll)
+#define iio_buffer_read_first_n_outer_addr (&iio_buffer_read_first_n_outer)
+
+#else
+
+#define iio_buffer_poll_addr NULL
+#define iio_buffer_read_first_n_outer_addr NULL
+
+#endif
+
+int iio_device_register_eventset(struct iio_dev *indio_dev);
+void iio_device_unregister_eventset(struct iio_dev *indio_dev);
+int iio_event_getfd(struct iio_dev *indio_dev);
+
+#endif
diff --git a/drivers/iio/iio_core_trigger.h b/drivers/iio/iio_core_trigger.h
new file mode 100644
index 00000000000..6f7c56fcbe7
--- /dev/null
+++ b/drivers/iio/iio_core_trigger.h
@@ -0,0 +1,46 @@
+
+/* The industrial I/O core, trigger consumer handling functions
+ *
+ * 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.
+ */
+
+#ifdef CONFIG_IIO_TRIGGER
+/**
+ * iio_device_register_trigger_consumer() - set up an iio_dev to use triggers
+ * @indio_dev: iio_dev associated with the device that will consume the trigger
+ **/
+void iio_device_register_trigger_consumer(struct iio_dev *indio_dev);
+
+/**
+ * iio_device_unregister_trigger_consumer() - reverse the registration process
+ * @indio_dev: iio_dev associated with the device that consumed the trigger
+ **/
+void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev);
+
+#else
+
+/**
+ * iio_device_register_trigger_consumer() - set up an iio_dev to use triggers
+ * @indio_dev: iio_dev associated with the device that will consume the trigger
+ **/
+static int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
+{
+	return 0;
+};
+
+/**
+ * iio_device_unregister_trigger_consumer() - reverse the registration process
+ * @indio_dev: iio_dev associated with the device that consumed the trigger
+ **/
+static void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
+{
+};
+
+#endif /* CONFIG_TRIGGER_CONSUMER */
+
+
+
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
new file mode 100644
index 00000000000..b5b2c38045c
--- /dev/null
+++ b/drivers/iio/industrialio-buffer.c
@@ -0,0 +1,755 @@
+/* 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.
+ *
+ * Handling of buffer allocation / resizing.
+ *
+ *
+ * Things to look at here.
+ * - Better memory allocation techniques?
+ * - Alternative access techniques?
+ */
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+
+#include <linux/iio/iio.h>
+#include "iio_core.h"
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+
+static const char * const iio_endian_prefix[] = {
+	[IIO_BE] = "be",
+	[IIO_LE] = "le",
+};
+
+/**
+ * iio_buffer_read_first_n_outer() - chrdev read for buffer access
+ *
+ * This function relies on all buffer implementations having an
+ * iio_buffer as their first element.
+ **/
+ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
+				      size_t n, loff_t *f_ps)
+{
+	struct iio_dev *indio_dev = filp->private_data;
+	struct iio_buffer *rb = indio_dev->buffer;
+
+	if (!rb || !rb->access->read_first_n)
+		return -EINVAL;
+	return rb->access->read_first_n(rb, n, buf);
+}
+
+/**
+ * iio_buffer_poll() - poll the buffer to find out if it has data
+ */
+unsigned int iio_buffer_poll(struct file *filp,
+			     struct poll_table_struct *wait)
+{
+	struct iio_dev *indio_dev = filp->private_data;
+	struct iio_buffer *rb = indio_dev->buffer;
+
+	poll_wait(filp, &rb->pollq, wait);
+	if (rb->stufftoread)
+		return POLLIN | POLLRDNORM;
+	/* need a way of knowing if there may be enough data... */
+	return 0;
+}
+
+void iio_buffer_init(struct iio_buffer *buffer)
+{
+	INIT_LIST_HEAD(&buffer->demux_list);
+	init_waitqueue_head(&buffer->pollq);
+}
+EXPORT_SYMBOL(iio_buffer_init);
+
+static ssize_t iio_show_scan_index(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
+}
+
+static ssize_t iio_show_fixed_type(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	u8 type = this_attr->c->scan_type.endianness;
+
+	if (type == IIO_CPU) {
+#ifdef __LITTLE_ENDIAN
+		type = IIO_LE;
+#else
+		type = IIO_BE;
+#endif
+	}
+	return sprintf(buf, "%s:%c%d/%d>>%u\n",
+		       iio_endian_prefix[type],
+		       this_attr->c->scan_type.sign,
+		       this_attr->c->scan_type.realbits,
+		       this_attr->c->scan_type.storagebits,
+		       this_attr->c->scan_type.shift);
+}
+
+static ssize_t iio_scan_el_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	int ret;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+
+	ret = test_bit(to_iio_dev_attr(attr)->address,
+		       indio_dev->buffer->scan_mask);
+
+	return sprintf(buf, "%d\n", ret);
+}
+
+static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
+{
+	clear_bit(bit, buffer->scan_mask);
+	return 0;
+}
+
+static ssize_t iio_scan_el_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf,
+				 size_t len)
+{
+	int ret;
+	bool state;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_buffer *buffer = indio_dev->buffer;
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	ret = strtobool(buf, &state);
+	if (ret < 0)
+		return ret;
+	mutex_lock(&indio_dev->mlock);
+	if (iio_buffer_enabled(indio_dev)) {
+		ret = -EBUSY;
+		goto error_ret;
+	}
+	ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
+	if (ret < 0)
+		goto error_ret;
+	if (!state && ret) {
+		ret = iio_scan_mask_clear(buffer, this_attr->address);
+		if (ret)
+			goto error_ret;
+	} else if (state && !ret) {
+		ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
+		if (ret)
+			goto error_ret;
+	}
+
+error_ret:
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret < 0 ? ret : len;
+
+}
+
+static ssize_t iio_scan_el_ts_show(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
+}
+
+static ssize_t iio_scan_el_ts_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf,
+				    size_t len)
+{
+	int ret;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	bool state;
+
+	ret = strtobool(buf, &state);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&indio_dev->mlock);
+	if (iio_buffer_enabled(indio_dev)) {
+		ret = -EBUSY;
+		goto error_ret;
+	}
+	indio_dev->buffer->scan_timestamp = state;
+	indio_dev->scan_timestamp = state;
+error_ret:
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret ? ret : len;
+}
+
+static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan)
+{
+	int ret, attrcount = 0;
+	struct iio_buffer *buffer = indio_dev->buffer;
+
+	ret = __iio_add_chan_devattr("index",
+				     chan,
+				     &iio_show_scan_index,
+				     NULL,
+				     0,
+				     0,
+				     &indio_dev->dev,
+				     &buffer->scan_el_dev_attr_list);
+	if (ret)
+		goto error_ret;
+	attrcount++;
+	ret = __iio_add_chan_devattr("type",
+				     chan,
+				     &iio_show_fixed_type,
+				     NULL,
+				     0,
+				     0,
+				     &indio_dev->dev,
+				     &buffer->scan_el_dev_attr_list);
+	if (ret)
+		goto error_ret;
+	attrcount++;
+	if (chan->type != IIO_TIMESTAMP)
+		ret = __iio_add_chan_devattr("en",
+					     chan,
+					     &iio_scan_el_show,
+					     &iio_scan_el_store,
+					     chan->scan_index,
+					     0,
+					     &indio_dev->dev,
+					     &buffer->scan_el_dev_attr_list);
+	else
+		ret = __iio_add_chan_devattr("en",
+					     chan,
+					     &iio_scan_el_ts_show,
+					     &iio_scan_el_ts_store,
+					     chan->scan_index,
+					     0,
+					     &indio_dev->dev,
+					     &buffer->scan_el_dev_attr_list);
+	attrcount++;
+	ret = attrcount;
+error_ret:
+	return ret;
+}
+
+static void iio_buffer_remove_and_free_scan_dev_attr(struct iio_dev *indio_dev,
+						     struct iio_dev_attr *p)
+{
+	kfree(p->dev_attr.attr.name);
+	kfree(p);
+}
+
+static void __iio_buffer_attr_cleanup(struct iio_dev *indio_dev)
+{
+	struct iio_dev_attr *p, *n;
+	struct iio_buffer *buffer = indio_dev->buffer;
+
+	list_for_each_entry_safe(p, n,
+				 &buffer->scan_el_dev_attr_list, l)
+		iio_buffer_remove_and_free_scan_dev_attr(indio_dev, p);
+}
+
+static const char * const iio_scan_elements_group_name = "scan_elements";
+
+int iio_buffer_register(struct iio_dev *indio_dev,
+			const struct iio_chan_spec *channels,
+			int num_channels)
+{
+	struct iio_dev_attr *p;
+	struct attribute **attr;
+	struct iio_buffer *buffer = indio_dev->buffer;
+	int ret, i, attrn, attrcount, attrcount_orig = 0;
+
+	if (buffer->attrs)
+		indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
+
+	if (buffer->scan_el_attrs != NULL) {
+		attr = buffer->scan_el_attrs->attrs;
+		while (*attr++ != NULL)
+			attrcount_orig++;
+	}
+	attrcount = attrcount_orig;
+	INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
+	if (channels) {
+		/* new magic */
+		for (i = 0; i < num_channels; i++) {
+			/* Establish necessary mask length */
+			if (channels[i].scan_index >
+			    (int)indio_dev->masklength - 1)
+				indio_dev->masklength
+					= indio_dev->channels[i].scan_index + 1;
+
+			ret = iio_buffer_add_channel_sysfs(indio_dev,
+							 &channels[i]);
+			if (ret < 0)
+				goto error_cleanup_dynamic;
+			attrcount += ret;
+			if (channels[i].type == IIO_TIMESTAMP)
+				indio_dev->scan_index_timestamp =
+					channels[i].scan_index;
+		}
+		if (indio_dev->masklength && buffer->scan_mask == NULL) {
+			buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
+						    sizeof(*buffer->scan_mask),
+						    GFP_KERNEL);
+			if (buffer->scan_mask == NULL) {
+				ret = -ENOMEM;
+				goto error_cleanup_dynamic;
+			}
+		}
+	}
+
+	buffer->scan_el_group.name = iio_scan_elements_group_name;
+
+	buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
+					      sizeof(buffer->scan_el_group.attrs[0]),
+					      GFP_KERNEL);
+	if (buffer->scan_el_group.attrs == NULL) {
+		ret = -ENOMEM;
+		goto error_free_scan_mask;
+	}
+	if (buffer->scan_el_attrs)
+		memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
+		       sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
+	attrn = attrcount_orig;
+
+	list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
+		buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
+	indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
+
+	return 0;
+
+error_free_scan_mask:
+	kfree(buffer->scan_mask);
+error_cleanup_dynamic:
+	__iio_buffer_attr_cleanup(indio_dev);
+
+	return ret;
+}
+EXPORT_SYMBOL(iio_buffer_register);
+
+void iio_buffer_unregister(struct iio_dev *indio_dev)
+{
+	kfree(indio_dev->buffer->scan_mask);
+	kfree(indio_dev->buffer->scan_el_group.attrs);
+	__iio_buffer_attr_cleanup(indio_dev);
+}
+EXPORT_SYMBOL(iio_buffer_unregister);
+
+ssize_t iio_buffer_read_length(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_buffer *buffer = indio_dev->buffer;
+
+	if (buffer->access->get_length)
+		return sprintf(buf, "%d\n",
+			       buffer->access->get_length(buffer));
+
+	return 0;
+}
+EXPORT_SYMBOL(iio_buffer_read_length);
+
+ssize_t iio_buffer_write_length(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf,
+				size_t len)
+{
+	int ret;
+	ulong val;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_buffer *buffer = indio_dev->buffer;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (buffer->access->get_length)
+		if (val == buffer->access->get_length(buffer))
+			return len;
+
+	mutex_lock(&indio_dev->mlock);
+	if (iio_buffer_enabled(indio_dev)) {
+		ret = -EBUSY;
+	} else {
+		if (buffer->access->set_length)
+			buffer->access->set_length(buffer, val);
+		ret = 0;
+	}
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret ? ret : len;
+}
+EXPORT_SYMBOL(iio_buffer_write_length);
+
+ssize_t iio_buffer_store_enable(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf,
+				size_t len)
+{
+	int ret;
+	bool requested_state, current_state;
+	int previous_mode;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_buffer *buffer = indio_dev->buffer;
+
+	mutex_lock(&indio_dev->mlock);
+	previous_mode = indio_dev->currentmode;
+	requested_state = !(buf[0] == '0');
+	current_state = iio_buffer_enabled(indio_dev);
+	if (current_state == requested_state) {
+		printk(KERN_INFO "iio-buffer, current state requested again\n");
+		goto done;
+	}
+	if (requested_state) {
+		if (indio_dev->setup_ops->preenable) {
+			ret = indio_dev->setup_ops->preenable(indio_dev);
+			if (ret) {
+				printk(KERN_ERR
+				       "Buffer not started:"
+				       "buffer preenable failed\n");
+				goto error_ret;
+			}
+		}
+		if (buffer->access->request_update) {
+			ret = buffer->access->request_update(buffer);
+			if (ret) {
+				printk(KERN_INFO
+				       "Buffer not started:"
+				       "buffer parameter update failed\n");
+				goto error_ret;
+			}
+		}
+		/* Definitely possible for devices to support both of these.*/
+		if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
+			if (!indio_dev->trig) {
+				printk(KERN_INFO
+				       "Buffer not started: no trigger\n");
+				ret = -EINVAL;
+				goto error_ret;
+			}
+			indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
+		} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE)
+			indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
+		else { /* should never be reached */
+			ret = -EINVAL;
+			goto error_ret;
+		}
+
+		if (indio_dev->setup_ops->postenable) {
+			ret = indio_dev->setup_ops->postenable(indio_dev);
+			if (ret) {
+				printk(KERN_INFO
+				       "Buffer not started:"
+				       "postenable failed\n");
+				indio_dev->currentmode = previous_mode;
+				if (indio_dev->setup_ops->postdisable)
+					indio_dev->setup_ops->
+						postdisable(indio_dev);
+				goto error_ret;
+			}
+		}
+	} else {
+		if (indio_dev->setup_ops->predisable) {
+			ret = indio_dev->setup_ops->predisable(indio_dev);
+			if (ret)
+				goto error_ret;
+		}
+		indio_dev->currentmode = INDIO_DIRECT_MODE;
+		if (indio_dev->setup_ops->postdisable) {
+			ret = indio_dev->setup_ops->postdisable(indio_dev);
+			if (ret)
+				goto error_ret;
+		}
+	}
+done:
+	mutex_unlock(&indio_dev->mlock);
+	return len;
+
+error_ret:
+	mutex_unlock(&indio_dev->mlock);
+	return ret;
+}
+EXPORT_SYMBOL(iio_buffer_store_enable);
+
+ssize_t iio_buffer_show_enable(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	return sprintf(buf, "%d\n", iio_buffer_enabled(indio_dev));
+}
+EXPORT_SYMBOL(iio_buffer_show_enable);
+
+/* note NULL used as error indicator as it doesn't make sense. */
+static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
+					  unsigned int masklength,
+					  const unsigned long *mask)
+{
+	if (bitmap_empty(mask, masklength))
+		return NULL;
+	while (*av_masks) {
+		if (bitmap_subset(mask, av_masks, masklength))
+			return av_masks;
+		av_masks += BITS_TO_LONGS(masklength);
+	}
+	return NULL;
+}
+
+static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
+				  bool timestamp)
+{
+	const struct iio_chan_spec *ch;
+	unsigned bytes = 0;
+	int length, i;
+
+	/* How much space will the demuxed element take? */
+	for_each_set_bit(i, mask,
+			 indio_dev->masklength) {
+		ch = iio_find_channel_from_si(indio_dev, i);
+		length = ch->scan_type.storagebits / 8;
+		bytes = ALIGN(bytes, length);
+		bytes += length;
+	}
+	if (timestamp) {
+		ch = iio_find_channel_from_si(indio_dev,
+					      indio_dev->scan_index_timestamp);
+		length = ch->scan_type.storagebits / 8;
+		bytes = ALIGN(bytes, length);
+		bytes += length;
+	}
+	return bytes;
+}
+
+int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
+{
+	struct iio_buffer *buffer = indio_dev->buffer;
+	dev_dbg(&indio_dev->dev, "%s\n", __func__);
+
+	/* How much space will the demuxed element take? */
+	indio_dev->scan_bytes =
+		iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
+				       buffer->scan_timestamp);
+	buffer->access->set_bytes_per_datum(buffer, indio_dev->scan_bytes);
+
+	/* What scan mask do we actually have ?*/
+	if (indio_dev->available_scan_masks)
+		indio_dev->active_scan_mask =
+			iio_scan_mask_match(indio_dev->available_scan_masks,
+					    indio_dev->masklength,
+					    buffer->scan_mask);
+	else
+		indio_dev->active_scan_mask = buffer->scan_mask;
+	iio_update_demux(indio_dev);
+
+	if (indio_dev->info->update_scan_mode)
+		return indio_dev->info
+			->update_scan_mode(indio_dev,
+					   indio_dev->active_scan_mask);
+	return 0;
+}
+EXPORT_SYMBOL(iio_sw_buffer_preenable);
+
+/**
+ * iio_scan_mask_set() - set particular bit in the scan mask
+ * @buffer: the buffer whose scan mask we are interested in
+ * @bit: the bit to be set.
+ **/
+int iio_scan_mask_set(struct iio_dev *indio_dev,
+		      struct iio_buffer *buffer, int bit)
+{
+	const unsigned long *mask;
+	unsigned long *trialmask;
+
+	trialmask = kmalloc(sizeof(*trialmask)*
+			    BITS_TO_LONGS(indio_dev->masklength),
+			    GFP_KERNEL);
+
+	if (trialmask == NULL)
+		return -ENOMEM;
+	if (!indio_dev->masklength) {
+		WARN_ON("trying to set scanmask prior to registering buffer\n");
+		kfree(trialmask);
+		return -EINVAL;
+	}
+	bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
+	set_bit(bit, trialmask);
+
+	if (indio_dev->available_scan_masks) {
+		mask = iio_scan_mask_match(indio_dev->available_scan_masks,
+					   indio_dev->masklength,
+					   trialmask);
+		if (!mask) {
+			kfree(trialmask);
+			return -EINVAL;
+		}
+	}
+	bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
+
+	kfree(trialmask);
+
+	return 0;
+};
+EXPORT_SYMBOL_GPL(iio_scan_mask_set);
+
+int iio_scan_mask_query(struct iio_dev *indio_dev,
+			struct iio_buffer *buffer, int bit)
+{
+	if (bit > indio_dev->masklength)
+		return -EINVAL;
+
+	if (!buffer->scan_mask)
+		return 0;
+
+	return test_bit(bit, buffer->scan_mask);
+};
+EXPORT_SYMBOL_GPL(iio_scan_mask_query);
+
+/**
+ * struct iio_demux_table() - table describing demux memcpy ops
+ * @from:	index to copy from
+ * @to:	index to copy to
+ * @length:	how many bytes to copy
+ * @l:		list head used for management
+ */
+struct iio_demux_table {
+	unsigned from;
+	unsigned to;
+	unsigned length;
+	struct list_head l;
+};
+
+static unsigned char *iio_demux(struct iio_buffer *buffer,
+				 unsigned char *datain)
+{
+	struct iio_demux_table *t;
+
+	if (list_empty(&buffer->demux_list))
+		return datain;
+	list_for_each_entry(t, &buffer->demux_list, l)
+		memcpy(buffer->demux_bounce + t->to,
+		       datain + t->from, t->length);
+
+	return buffer->demux_bounce;
+}
+
+int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data,
+		       s64 timestamp)
+{
+	unsigned char *dataout = iio_demux(buffer, data);
+
+	return buffer->access->store_to(buffer, dataout, timestamp);
+}
+EXPORT_SYMBOL_GPL(iio_push_to_buffer);
+
+static void iio_buffer_demux_free(struct iio_buffer *buffer)
+{
+	struct iio_demux_table *p, *q;
+	list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
+		list_del(&p->l);
+		kfree(p);
+	}
+}
+
+int iio_update_demux(struct iio_dev *indio_dev)
+{
+	const struct iio_chan_spec *ch;
+	struct iio_buffer *buffer = indio_dev->buffer;
+	int ret, in_ind = -1, out_ind, length;
+	unsigned in_loc = 0, out_loc = 0;
+	struct iio_demux_table *p;
+
+	/* Clear out any old demux */
+	iio_buffer_demux_free(buffer);
+	kfree(buffer->demux_bounce);
+	buffer->demux_bounce = NULL;
+
+	/* First work out which scan mode we will actually have */
+	if (bitmap_equal(indio_dev->active_scan_mask,
+			 buffer->scan_mask,
+			 indio_dev->masklength))
+		return 0;
+
+	/* Now we have the two masks, work from least sig and build up sizes */
+	for_each_set_bit(out_ind,
+			 indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		in_ind = find_next_bit(indio_dev->active_scan_mask,
+				       indio_dev->masklength,
+				       in_ind + 1);
+		while (in_ind != out_ind) {
+			in_ind = find_next_bit(indio_dev->active_scan_mask,
+					       indio_dev->masklength,
+					       in_ind + 1);
+			ch = iio_find_channel_from_si(indio_dev, in_ind);
+			length = ch->scan_type.storagebits/8;
+			/* Make sure we are aligned */
+			in_loc += length;
+			if (in_loc % length)
+				in_loc += length - in_loc % length;
+		}
+		p = kmalloc(sizeof(*p), GFP_KERNEL);
+		if (p == NULL) {
+			ret = -ENOMEM;
+			goto error_clear_mux_table;
+		}
+		ch = iio_find_channel_from_si(indio_dev, in_ind);
+		length = ch->scan_type.storagebits/8;
+		if (out_loc % length)
+			out_loc += length - out_loc % length;
+		if (in_loc % length)
+			in_loc += length - in_loc % length;
+		p->from = in_loc;
+		p->to = out_loc;
+		p->length = length;
+		list_add_tail(&p->l, &buffer->demux_list);
+		out_loc += length;
+		in_loc += length;
+	}
+	/* Relies on scan_timestamp being last */
+	if (buffer->scan_timestamp) {
+		p = kmalloc(sizeof(*p), GFP_KERNEL);
+		if (p == NULL) {
+			ret = -ENOMEM;
+			goto error_clear_mux_table;
+		}
+		ch = iio_find_channel_from_si(indio_dev,
+			indio_dev->scan_index_timestamp);
+		length = ch->scan_type.storagebits/8;
+		if (out_loc % length)
+			out_loc += length - out_loc % length;
+		if (in_loc % length)
+			in_loc += length - in_loc % length;
+		p->from = in_loc;
+		p->to = out_loc;
+		p->length = length;
+		list_add_tail(&p->l, &buffer->demux_list);
+		out_loc += length;
+		in_loc += length;
+	}
+	buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
+	if (buffer->demux_bounce == NULL) {
+		ret = -ENOMEM;
+		goto error_clear_mux_table;
+	}
+	return 0;
+
+error_clear_mux_table:
+	iio_buffer_demux_free(buffer);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_update_demux);
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
new file mode 100644
index 00000000000..dd1a6a2e81c
--- /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");
diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
new file mode 100644
index 00000000000..5fcf50b1ae5
--- /dev/null
+++ b/drivers/iio/industrialio-event.c
@@ -0,0 +1,453 @@
+/* Industrial I/O event handling
+ *
+ * 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/anon_inodes.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include <linux/iio/iio.h>
+#include "iio_core.h"
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+/**
+ * struct iio_event_interface - chrdev interface for an event line
+ * @wait:		wait queue to allow blocking reads of events
+ * @det_events:		list of detected events
+ * @dev_attr_list:	list of event interface sysfs attribute
+ * @flags:		file operations related flags including busy flag.
+ * @group:		event interface sysfs attribute group
+ */
+struct iio_event_interface {
+	wait_queue_head_t	wait;
+	DECLARE_KFIFO(det_events, struct iio_event_data, 16);
+
+	struct list_head	dev_attr_list;
+	unsigned long		flags;
+	struct attribute_group	group;
+};
+
+int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
+{
+	struct iio_event_interface *ev_int = indio_dev->event_interface;
+	struct iio_event_data ev;
+	int copied;
+
+	/* Does anyone care? */
+	spin_lock(&ev_int->wait.lock);
+	if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
+
+		ev.id = ev_code;
+		ev.timestamp = timestamp;
+
+		copied = kfifo_put(&ev_int->det_events, &ev);
+		if (copied != 0)
+			wake_up_locked_poll(&ev_int->wait, POLLIN);
+	}
+	spin_unlock(&ev_int->wait.lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(iio_push_event);
+
+/**
+ * iio_event_poll() - poll the event queue to find out if it has data
+ */
+static unsigned int iio_event_poll(struct file *filep,
+			     struct poll_table_struct *wait)
+{
+	struct iio_event_interface *ev_int = filep->private_data;
+	unsigned int events = 0;
+
+	poll_wait(filep, &ev_int->wait, wait);
+
+	spin_lock(&ev_int->wait.lock);
+	if (!kfifo_is_empty(&ev_int->det_events))
+		events = POLLIN | POLLRDNORM;
+	spin_unlock(&ev_int->wait.lock);
+
+	return events;
+}
+
+static ssize_t iio_event_chrdev_read(struct file *filep,
+				     char __user *buf,
+				     size_t count,
+				     loff_t *f_ps)
+{
+	struct iio_event_interface *ev_int = filep->private_data;
+	unsigned int copied;
+	int ret;
+
+	if (count < sizeof(struct iio_event_data))
+		return -EINVAL;
+
+	spin_lock(&ev_int->wait.lock);
+	if (kfifo_is_empty(&ev_int->det_events)) {
+		if (filep->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
+			goto error_unlock;
+		}
+		/* Blocking on device; waiting for something to be there */
+		ret = wait_event_interruptible_locked(ev_int->wait,
+					!kfifo_is_empty(&ev_int->det_events));
+		if (ret)
+			goto error_unlock;
+		/* Single access device so no one else can get the data */
+	}
+
+	ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
+
+error_unlock:
+	spin_unlock(&ev_int->wait.lock);
+
+	return ret ? ret : copied;
+}
+
+static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
+{
+	struct iio_event_interface *ev_int = filep->private_data;
+
+	spin_lock(&ev_int->wait.lock);
+	__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
+	/*
+	 * In order to maintain a clean state for reopening,
+	 * clear out any awaiting events. The mask will prevent
+	 * any new __iio_push_event calls running.
+	 */
+	kfifo_reset_out(&ev_int->det_events);
+	spin_unlock(&ev_int->wait.lock);
+
+	return 0;
+}
+
+static const struct file_operations iio_event_chrdev_fileops = {
+	.read =  iio_event_chrdev_read,
+	.poll =  iio_event_poll,
+	.release = iio_event_chrdev_release,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+};
+
+int iio_event_getfd(struct iio_dev *indio_dev)
+{
+	struct iio_event_interface *ev_int = indio_dev->event_interface;
+	int fd;
+
+	if (ev_int == NULL)
+		return -ENODEV;
+
+	spin_lock(&ev_int->wait.lock);
+	if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
+		spin_unlock(&ev_int->wait.lock);
+		return -EBUSY;
+	}
+	spin_unlock(&ev_int->wait.lock);
+	fd = anon_inode_getfd("iio:event",
+				&iio_event_chrdev_fileops, ev_int, O_RDONLY);
+	if (fd < 0) {
+		spin_lock(&ev_int->wait.lock);
+		__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
+		spin_unlock(&ev_int->wait.lock);
+	}
+	return fd;
+}
+
+static const char * const iio_ev_type_text[] = {
+	[IIO_EV_TYPE_THRESH] = "thresh",
+	[IIO_EV_TYPE_MAG] = "mag",
+	[IIO_EV_TYPE_ROC] = "roc",
+	[IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
+	[IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
+};
+
+static const char * const iio_ev_dir_text[] = {
+	[IIO_EV_DIR_EITHER] = "either",
+	[IIO_EV_DIR_RISING] = "rising",
+	[IIO_EV_DIR_FALLING] = "falling"
+};
+
+static ssize_t iio_ev_state_store(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;
+	bool val;
+
+	ret = strtobool(buf, &val);
+	if (ret < 0)
+		return ret;
+
+	ret = indio_dev->info->write_event_config(indio_dev,
+						  this_attr->address,
+						  val);
+	return (ret < 0) ? ret : len;
+}
+
+static ssize_t iio_ev_state_show(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 = indio_dev->info->read_event_config(indio_dev,
+						     this_attr->address);
+
+	if (val < 0)
+		return val;
+	else
+		return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t iio_ev_value_show(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, ret;
+
+	ret = indio_dev->info->read_event_value(indio_dev,
+						this_attr->address, &val);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t iio_ev_value_store(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);
+	unsigned long val;
+	int ret;
+
+	if (!indio_dev->info->write_event_value)
+		return -EINVAL;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	ret = indio_dev->info->write_event_value(indio_dev, this_attr->address,
+						 val);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
+				      struct iio_chan_spec const *chan)
+{
+	int ret = 0, i, attrcount = 0;
+	u64 mask = 0;
+	char *postfix;
+	if (!chan->event_mask)
+		return 0;
+
+	for_each_set_bit(i, &chan->event_mask, sizeof(chan->event_mask)*8) {
+		postfix = kasprintf(GFP_KERNEL, "%s_%s_en",
+				    iio_ev_type_text[i/IIO_EV_DIR_MAX],
+				    iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
+		if (postfix == NULL) {
+			ret = -ENOMEM;
+			goto error_ret;
+		}
+		if (chan->modified)
+			mask = IIO_MOD_EVENT_CODE(chan->type, 0, chan->channel,
+						  i/IIO_EV_DIR_MAX,
+						  i%IIO_EV_DIR_MAX);
+		else if (chan->differential)
+			mask = IIO_EVENT_CODE(chan->type,
+					      0, 0,
+					      i%IIO_EV_DIR_MAX,
+					      i/IIO_EV_DIR_MAX,
+					      0,
+					      chan->channel,
+					      chan->channel2);
+		else
+			mask = IIO_UNMOD_EVENT_CODE(chan->type,
+						    chan->channel,
+						    i/IIO_EV_DIR_MAX,
+						    i%IIO_EV_DIR_MAX);
+
+		ret = __iio_add_chan_devattr(postfix,
+					     chan,
+					     &iio_ev_state_show,
+					     iio_ev_state_store,
+					     mask,
+					     0,
+					     &indio_dev->dev,
+					     &indio_dev->event_interface->
+					     dev_attr_list);
+		kfree(postfix);
+		if (ret)
+			goto error_ret;
+		attrcount++;
+		postfix = kasprintf(GFP_KERNEL, "%s_%s_value",
+				    iio_ev_type_text[i/IIO_EV_DIR_MAX],
+				    iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
+		if (postfix == NULL) {
+			ret = -ENOMEM;
+			goto error_ret;
+		}
+		ret = __iio_add_chan_devattr(postfix, chan,
+					     iio_ev_value_show,
+					     iio_ev_value_store,
+					     mask,
+					     0,
+					     &indio_dev->dev,
+					     &indio_dev->event_interface->
+					     dev_attr_list);
+		kfree(postfix);
+		if (ret)
+			goto error_ret;
+		attrcount++;
+	}
+	ret = attrcount;
+error_ret:
+	return ret;
+}
+
+static inline void __iio_remove_event_config_attrs(struct iio_dev *indio_dev)
+{
+	struct iio_dev_attr *p, *n;
+	list_for_each_entry_safe(p, n,
+				 &indio_dev->event_interface->
+				 dev_attr_list, l) {
+		kfree(p->dev_attr.attr.name);
+		kfree(p);
+	}
+}
+
+static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
+{
+	int j, ret, attrcount = 0;
+
+	INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
+	/* Dynically created from the channels array */
+	for (j = 0; j < indio_dev->num_channels; j++) {
+		ret = iio_device_add_event_sysfs(indio_dev,
+						 &indio_dev->channels[j]);
+		if (ret < 0)
+			goto error_clear_attrs;
+		attrcount += ret;
+	}
+	return attrcount;
+
+error_clear_attrs:
+	__iio_remove_event_config_attrs(indio_dev);
+
+	return ret;
+}
+
+static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
+{
+	int j;
+
+	for (j = 0; j < indio_dev->num_channels; j++)
+		if (indio_dev->channels[j].event_mask != 0)
+			return true;
+	return false;
+}
+
+static void iio_setup_ev_int(struct iio_event_interface *ev_int)
+{
+	INIT_KFIFO(ev_int->det_events);
+	init_waitqueue_head(&ev_int->wait);
+}
+
+static const char *iio_event_group_name = "events";
+int iio_device_register_eventset(struct iio_dev *indio_dev)
+{
+	struct iio_dev_attr *p;
+	int ret = 0, attrcount_orig = 0, attrcount, attrn;
+	struct attribute **attr;
+
+	if (!(indio_dev->info->event_attrs ||
+	      iio_check_for_dynamic_events(indio_dev)))
+		return 0;
+
+	indio_dev->event_interface =
+		kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
+	if (indio_dev->event_interface == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	iio_setup_ev_int(indio_dev->event_interface);
+	if (indio_dev->info->event_attrs != NULL) {
+		attr = indio_dev->info->event_attrs->attrs;
+		while (*attr++ != NULL)
+			attrcount_orig++;
+	}
+	attrcount = attrcount_orig;
+	if (indio_dev->channels) {
+		ret = __iio_add_event_config_attrs(indio_dev);
+		if (ret < 0)
+			goto error_free_setup_event_lines;
+		attrcount += ret;
+	}
+
+	indio_dev->event_interface->group.name = iio_event_group_name;
+	indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
+							  sizeof(indio_dev->event_interface->group.attrs[0]),
+							  GFP_KERNEL);
+	if (indio_dev->event_interface->group.attrs == NULL) {
+		ret = -ENOMEM;
+		goto error_free_setup_event_lines;
+	}
+	if (indio_dev->info->event_attrs)
+		memcpy(indio_dev->event_interface->group.attrs,
+		       indio_dev->info->event_attrs->attrs,
+		       sizeof(indio_dev->event_interface->group.attrs[0])
+		       *attrcount_orig);
+	attrn = attrcount_orig;
+	/* Add all elements from the list. */
+	list_for_each_entry(p,
+			    &indio_dev->event_interface->dev_attr_list,
+			    l)
+		indio_dev->event_interface->group.attrs[attrn++] =
+			&p->dev_attr.attr;
+	indio_dev->groups[indio_dev->groupcounter++] =
+		&indio_dev->event_interface->group;
+
+	return 0;
+
+error_free_setup_event_lines:
+	__iio_remove_event_config_attrs(indio_dev);
+	kfree(indio_dev->event_interface);
+error_ret:
+
+	return ret;
+}
+
+void iio_device_unregister_eventset(struct iio_dev *indio_dev)
+{
+	if (indio_dev->event_interface == NULL)
+		return;
+	__iio_remove_event_config_attrs(indio_dev);
+	kfree(indio_dev->event_interface->group.attrs);
+	kfree(indio_dev->event_interface);
+}
diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
new file mode 100644
index 00000000000..03fee2e097c
--- /dev/null
+++ b/drivers/iio/industrialio-trigger.c
@@ -0,0 +1,509 @@
+/* The industrial I/O core, trigger handling functions
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/idr.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+#include "iio_core.h"
+#include "iio_core_trigger.h"
+#include <linux/iio/trigger_consumer.h>
+
+/* RFC - Question of approach
+ * Make the common case (single sensor single trigger)
+ * simple by starting trigger capture from when first sensors
+ * is added.
+ *
+ * Complex simultaneous start requires use of 'hold' functionality
+ * of the trigger. (not implemented)
+ *
+ * Any other suggestions?
+ */
+
+static DEFINE_IDA(iio_trigger_ida);
+
+/* Single list of all available triggers */
+static LIST_HEAD(iio_trigger_list);
+static DEFINE_MUTEX(iio_trigger_list_lock);
+
+/**
+ * iio_trigger_read_name() - retrieve useful identifying name
+ **/
+static ssize_t iio_trigger_read_name(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct iio_trigger *trig = dev_get_drvdata(dev);
+	return sprintf(buf, "%s\n", trig->name);
+}
+
+static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
+
+/**
+ * iio_trigger_register_sysfs() - create a device for this trigger
+ * @trig_info:	the trigger
+ *
+ * Also adds any control attribute registered by the trigger driver
+ **/
+static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
+{
+	return sysfs_add_file_to_group(&trig_info->dev.kobj,
+				       &dev_attr_name.attr,
+				       NULL);
+}
+
+static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
+{
+	sysfs_remove_file_from_group(&trig_info->dev.kobj,
+					   &dev_attr_name.attr,
+					   NULL);
+}
+
+int iio_trigger_register(struct iio_trigger *trig_info)
+{
+	int ret;
+
+	trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
+	if (trig_info->id < 0) {
+		ret = trig_info->id;
+		goto error_ret;
+	}
+	/* Set the name used for the sysfs directory etc */
+	dev_set_name(&trig_info->dev, "trigger%ld",
+		     (unsigned long) trig_info->id);
+
+	ret = device_add(&trig_info->dev);
+	if (ret)
+		goto error_unregister_id;
+
+	ret = iio_trigger_register_sysfs(trig_info);
+	if (ret)
+		goto error_device_del;
+
+	/* Add to list of available triggers held by the IIO core */
+	mutex_lock(&iio_trigger_list_lock);
+	list_add_tail(&trig_info->list, &iio_trigger_list);
+	mutex_unlock(&iio_trigger_list_lock);
+
+	return 0;
+
+error_device_del:
+	device_del(&trig_info->dev);
+error_unregister_id:
+	ida_simple_remove(&iio_trigger_ida, trig_info->id);
+error_ret:
+	return ret;
+}
+EXPORT_SYMBOL(iio_trigger_register);
+
+void iio_trigger_unregister(struct iio_trigger *trig_info)
+{
+	mutex_lock(&iio_trigger_list_lock);
+	list_del(&trig_info->list);
+	mutex_unlock(&iio_trigger_list_lock);
+
+	iio_trigger_unregister_sysfs(trig_info);
+	ida_simple_remove(&iio_trigger_ida, trig_info->id);
+	/* Possible issue in here */
+	device_unregister(&trig_info->dev);
+}
+EXPORT_SYMBOL(iio_trigger_unregister);
+
+static struct iio_trigger *iio_trigger_find_by_name(const char *name,
+						    size_t len)
+{
+	struct iio_trigger *trig = NULL, *iter;
+
+	mutex_lock(&iio_trigger_list_lock);
+	list_for_each_entry(iter, &iio_trigger_list, list)
+		if (sysfs_streq(iter->name, name)) {
+			trig = iter;
+			break;
+		}
+	mutex_unlock(&iio_trigger_list_lock);
+
+	return trig;
+}
+
+void iio_trigger_poll(struct iio_trigger *trig, s64 time)
+{
+	int i;
+	if (!trig->use_count)
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
+			if (trig->subirqs[i].enabled) {
+				trig->use_count++;
+				generic_handle_irq(trig->subirq_base + i);
+			}
+}
+EXPORT_SYMBOL(iio_trigger_poll);
+
+irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
+{
+	iio_trigger_poll(private, iio_get_time_ns());
+	return IRQ_HANDLED;
+}
+EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
+
+void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
+{
+	int i;
+	if (!trig->use_count)
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
+			if (trig->subirqs[i].enabled) {
+				trig->use_count++;
+				handle_nested_irq(trig->subirq_base + i);
+			}
+}
+EXPORT_SYMBOL(iio_trigger_poll_chained);
+
+void iio_trigger_notify_done(struct iio_trigger *trig)
+{
+	trig->use_count--;
+	if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
+		if (trig->ops->try_reenable(trig))
+			/* Missed and interrupt so launch new poll now */
+			iio_trigger_poll(trig, 0);
+}
+EXPORT_SYMBOL(iio_trigger_notify_done);
+
+/* Trigger Consumer related functions */
+static int iio_trigger_get_irq(struct iio_trigger *trig)
+{
+	int ret;
+	mutex_lock(&trig->pool_lock);
+	ret = bitmap_find_free_region(trig->pool,
+				      CONFIG_IIO_CONSUMERS_PER_TRIGGER,
+				      ilog2(1));
+	mutex_unlock(&trig->pool_lock);
+	if (ret >= 0)
+		ret += trig->subirq_base;
+
+	return ret;
+}
+
+static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
+{
+	mutex_lock(&trig->pool_lock);
+	clear_bit(irq - trig->subirq_base, trig->pool);
+	mutex_unlock(&trig->pool_lock);
+}
+
+/* Complexity in here.  With certain triggers (datardy) an acknowledgement
+ * may be needed if the pollfuncs do not include the data read for the
+ * triggering device.
+ * This is not currently handled.  Alternative of not enabling trigger unless
+ * the relevant function is in there may be the best option.
+ */
+/* Worth protecting against double additions?*/
+static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
+					struct iio_poll_func *pf)
+{
+	int ret = 0;
+	bool notinuse
+		= bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+
+	/* Prevent the module being removed whilst attached to a trigger */
+	__module_get(pf->indio_dev->info->driver_module);
+	pf->irq = iio_trigger_get_irq(trig);
+	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
+				   pf->type, pf->name,
+				   pf);
+	if (ret < 0) {
+		module_put(pf->indio_dev->info->driver_module);
+		return ret;
+	}
+
+	if (trig->ops && trig->ops->set_trigger_state && notinuse) {
+		ret = trig->ops->set_trigger_state(trig, true);
+		if (ret < 0)
+			module_put(pf->indio_dev->info->driver_module);
+	}
+
+	return ret;
+}
+
+static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
+					 struct iio_poll_func *pf)
+{
+	int ret = 0;
+	bool no_other_users
+		= (bitmap_weight(trig->pool,
+				 CONFIG_IIO_CONSUMERS_PER_TRIGGER)
+		   == 1);
+	if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
+		ret = trig->ops->set_trigger_state(trig, false);
+		if (ret)
+			goto error_ret;
+	}
+	iio_trigger_put_irq(trig, pf->irq);
+	free_irq(pf->irq, pf);
+	module_put(pf->indio_dev->info->driver_module);
+
+error_ret:
+	return ret;
+}
+
+irqreturn_t iio_pollfunc_store_time(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	pf->timestamp = iio_get_time_ns();
+	return IRQ_WAKE_THREAD;
+}
+EXPORT_SYMBOL(iio_pollfunc_store_time);
+
+struct iio_poll_func
+*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
+		    irqreturn_t (*thread)(int irq, void *p),
+		    int type,
+		    struct iio_dev *indio_dev,
+		    const char *fmt,
+		    ...)
+{
+	va_list vargs;
+	struct iio_poll_func *pf;
+
+	pf = kmalloc(sizeof *pf, GFP_KERNEL);
+	if (pf == NULL)
+		return NULL;
+	va_start(vargs, fmt);
+	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
+	va_end(vargs);
+	if (pf->name == NULL) {
+		kfree(pf);
+		return NULL;
+	}
+	pf->h = h;
+	pf->thread = thread;
+	pf->type = type;
+	pf->indio_dev = indio_dev;
+
+	return pf;
+}
+EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
+
+void iio_dealloc_pollfunc(struct iio_poll_func *pf)
+{
+	kfree(pf->name);
+	kfree(pf);
+}
+EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
+
+/**
+ * iio_trigger_read_current() - trigger consumer sysfs query which trigger
+ *
+ * For trigger consumers the current_trigger interface allows the trigger
+ * used by the device to be queried.
+ **/
+static ssize_t iio_trigger_read_current(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+
+	if (indio_dev->trig)
+		return sprintf(buf, "%s\n", indio_dev->trig->name);
+	return 0;
+}
+
+/**
+ * iio_trigger_write_current() trigger consumer sysfs set current trigger
+ *
+ * For trigger consumers the current_trigger interface allows the trigger
+ * used for this device to be specified at run time based on the triggers
+ * name.
+ **/
+static ssize_t iio_trigger_write_current(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf,
+					 size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_trigger *oldtrig = indio_dev->trig;
+	struct iio_trigger *trig;
+	int ret;
+
+	mutex_lock(&indio_dev->mlock);
+	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+		mutex_unlock(&indio_dev->mlock);
+		return -EBUSY;
+	}
+	mutex_unlock(&indio_dev->mlock);
+
+	trig = iio_trigger_find_by_name(buf, len);
+	if (oldtrig == trig)
+		return len;
+
+	if (trig && indio_dev->info->validate_trigger) {
+		ret = indio_dev->info->validate_trigger(indio_dev, trig);
+		if (ret)
+			return ret;
+	}
+
+	if (trig && trig->ops && trig->ops->validate_device) {
+		ret = trig->ops->validate_device(trig, indio_dev);
+		if (ret)
+			return ret;
+	}
+
+	indio_dev->trig = trig;
+
+	if (oldtrig && indio_dev->trig != oldtrig)
+		iio_put_trigger(oldtrig);
+	if (indio_dev->trig)
+		iio_get_trigger(indio_dev->trig);
+
+	return len;
+}
+
+static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
+		   iio_trigger_read_current,
+		   iio_trigger_write_current);
+
+static struct attribute *iio_trigger_consumer_attrs[] = {
+	&dev_attr_current_trigger.attr,
+	NULL,
+};
+
+static const struct attribute_group iio_trigger_consumer_attr_group = {
+	.name = "trigger",
+	.attrs = iio_trigger_consumer_attrs,
+};
+
+static void iio_trig_release(struct device *device)
+{
+	struct iio_trigger *trig = to_iio_trigger(device);
+	int i;
+
+	if (trig->subirq_base) {
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+			irq_modify_status(trig->subirq_base + i,
+					  IRQ_NOAUTOEN,
+					  IRQ_NOREQUEST | IRQ_NOPROBE);
+			irq_set_chip(trig->subirq_base + i,
+				     NULL);
+			irq_set_handler(trig->subirq_base + i,
+					NULL);
+		}
+
+		irq_free_descs(trig->subirq_base,
+			       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+	}
+	kfree(trig->name);
+	kfree(trig);
+}
+
+static struct device_type iio_trig_type = {
+	.release = iio_trig_release,
+};
+
+static void iio_trig_subirqmask(struct irq_data *d)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct iio_trigger *trig
+		= container_of(chip,
+			       struct iio_trigger, subirq_chip);
+	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
+}
+
+static void iio_trig_subirqunmask(struct irq_data *d)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct iio_trigger *trig
+		= container_of(chip,
+			       struct iio_trigger, subirq_chip);
+	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
+}
+
+struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
+{
+	va_list vargs;
+	struct iio_trigger *trig;
+	trig = kzalloc(sizeof *trig, GFP_KERNEL);
+	if (trig) {
+		int i;
+		trig->dev.type = &iio_trig_type;
+		trig->dev.bus = &iio_bus_type;
+		device_initialize(&trig->dev);
+		dev_set_drvdata(&trig->dev, (void *)trig);
+
+		mutex_init(&trig->pool_lock);
+		trig->subirq_base
+			= irq_alloc_descs(-1, 0,
+					  CONFIG_IIO_CONSUMERS_PER_TRIGGER,
+					  0);
+		if (trig->subirq_base < 0) {
+			kfree(trig);
+			return NULL;
+		}
+		va_start(vargs, fmt);
+		trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
+		va_end(vargs);
+		if (trig->name == NULL) {
+			irq_free_descs(trig->subirq_base,
+				       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+			kfree(trig);
+			return NULL;
+		}
+		trig->subirq_chip.name = trig->name;
+		trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
+		trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+			irq_set_chip(trig->subirq_base + i,
+				     &trig->subirq_chip);
+			irq_set_handler(trig->subirq_base + i,
+					&handle_simple_irq);
+			irq_modify_status(trig->subirq_base + i,
+					  IRQ_NOREQUEST | IRQ_NOAUTOEN,
+					  IRQ_NOPROBE);
+		}
+		get_device(&trig->dev);
+	}
+	return trig;
+}
+EXPORT_SYMBOL(iio_allocate_trigger);
+
+void iio_free_trigger(struct iio_trigger *trig)
+{
+	if (trig)
+		put_device(&trig->dev);
+}
+EXPORT_SYMBOL(iio_free_trigger);
+
+void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
+{
+	indio_dev->groups[indio_dev->groupcounter++] =
+		&iio_trigger_consumer_attr_group;
+}
+
+void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
+{
+	/* Clean up and associated but not attached triggers references */
+	if (indio_dev->trig)
+		iio_put_trigger(indio_dev->trig);
+}
+
+int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
+{
+	return iio_trigger_attach_poll_func(indio_dev->trig,
+					    indio_dev->pollfunc);
+}
+EXPORT_SYMBOL(iio_triggered_buffer_postenable);
+
+int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
+{
+	return iio_trigger_dettach_poll_func(indio_dev->trig,
+					     indio_dev->pollfunc);
+}
+EXPORT_SYMBOL(iio_triggered_buffer_predisable);
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
new file mode 100644
index 00000000000..22ddf62b107
--- /dev/null
+++ b/drivers/iio/inkern.c
@@ -0,0 +1,292 @@
+/* The industrial I/O core in kernel channel mapping
+ *
+ * Copyright (c) 2011 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.
+ */
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+
+#include <linux/iio/iio.h>
+#include "iio_core.h"
+#include <linux/iio/machine.h>
+#include <linux/iio/driver.h>
+#include <linux/iio/consumer.h>
+
+struct iio_map_internal {
+	struct iio_dev *indio_dev;
+	struct iio_map *map;
+	struct list_head l;
+};
+
+static LIST_HEAD(iio_map_list);
+static DEFINE_MUTEX(iio_map_list_lock);
+
+int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
+{
+	int i = 0, ret = 0;
+	struct iio_map_internal *mapi;
+
+	if (maps == NULL)
+		return 0;
+
+	mutex_lock(&iio_map_list_lock);
+	while (maps[i].consumer_dev_name != NULL) {
+		mapi = kzalloc(sizeof(*mapi), GFP_KERNEL);
+		if (mapi == NULL) {
+			ret = -ENOMEM;
+			goto error_ret;
+		}
+		mapi->map = &maps[i];
+		mapi->indio_dev = indio_dev;
+		list_add(&mapi->l, &iio_map_list);
+		i++;
+	}
+error_ret:
+	mutex_unlock(&iio_map_list_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_map_array_register);
+
+
+/* Assumes the exact same array (e.g. memory locations)
+ * used at unregistration as used at registration rather than
+ * more complex checking of contents.
+ */
+int iio_map_array_unregister(struct iio_dev *indio_dev,
+			     struct iio_map *maps)
+{
+	int i = 0, ret = 0;
+	bool found_it;
+	struct iio_map_internal *mapi;
+
+	if (maps == NULL)
+		return 0;
+
+	mutex_lock(&iio_map_list_lock);
+	while (maps[i].consumer_dev_name != NULL) {
+		found_it = false;
+		list_for_each_entry(mapi, &iio_map_list, l)
+			if (&maps[i] == mapi->map) {
+				list_del(&mapi->l);
+				kfree(mapi);
+				found_it = true;
+				break;
+			}
+		if (found_it == false) {
+			ret = -ENODEV;
+			goto error_ret;
+		}
+	}
+error_ret:
+	mutex_unlock(&iio_map_list_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_map_array_unregister);
+
+static const struct iio_chan_spec
+*iio_chan_spec_from_name(const struct iio_dev *indio_dev,
+			 const char *name)
+{
+	int i;
+	const struct iio_chan_spec *chan = NULL;
+
+	for (i = 0; i < indio_dev->num_channels; i++)
+		if (indio_dev->channels[i].datasheet_name &&
+		    strcmp(name, indio_dev->channels[i].datasheet_name) == 0) {
+			chan = &indio_dev->channels[i];
+			break;
+		}
+	return chan;
+}
+
+
+struct iio_channel *iio_st_channel_get(const char *name,
+				       const char *channel_name)
+{
+	struct iio_map_internal *c_i = NULL, *c = NULL;
+	struct iio_channel *channel;
+
+	if (name == NULL && channel_name == NULL)
+		return ERR_PTR(-ENODEV);
+
+	/* first find matching entry the channel map */
+	mutex_lock(&iio_map_list_lock);
+	list_for_each_entry(c_i, &iio_map_list, l) {
+		if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
+		    (channel_name &&
+		     strcmp(channel_name, c_i->map->consumer_channel) != 0))
+			continue;
+		c = c_i;
+		get_device(&c->indio_dev->dev);
+		break;
+	}
+	mutex_unlock(&iio_map_list_lock);
+	if (c == NULL)
+		return ERR_PTR(-ENODEV);
+
+	channel = kmalloc(sizeof(*channel), GFP_KERNEL);
+	if (channel == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	channel->indio_dev = c->indio_dev;
+
+	if (c->map->adc_channel_label)
+		channel->channel =
+			iio_chan_spec_from_name(channel->indio_dev,
+						c->map->adc_channel_label);
+
+	return channel;
+}
+EXPORT_SYMBOL_GPL(iio_st_channel_get);
+
+void iio_st_channel_release(struct iio_channel *channel)
+{
+	put_device(&channel->indio_dev->dev);
+	kfree(channel);
+}
+EXPORT_SYMBOL_GPL(iio_st_channel_release);
+
+struct iio_channel *iio_st_channel_get_all(const char *name)
+{
+	struct iio_channel *chans;
+	struct iio_map_internal *c = NULL;
+	int nummaps = 0;
+	int mapind = 0;
+	int i, ret;
+
+	if (name == NULL)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&iio_map_list_lock);
+	/* first count the matching maps */
+	list_for_each_entry(c, &iio_map_list, l)
+		if (name && strcmp(name, c->map->consumer_dev_name) != 0)
+			continue;
+		else
+			nummaps++;
+
+	if (nummaps == 0) {
+		ret = -ENODEV;
+		goto error_ret;
+	}
+
+	/* NULL terminated array to save passing size */
+	chans = kzalloc(sizeof(*chans)*(nummaps + 1), GFP_KERNEL);
+	if (chans == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	/* for each map fill in the chans element */
+	list_for_each_entry(c, &iio_map_list, l) {
+		if (name && strcmp(name, c->map->consumer_dev_name) != 0)
+			continue;
+		chans[mapind].indio_dev = c->indio_dev;
+		chans[mapind].channel =
+			iio_chan_spec_from_name(chans[mapind].indio_dev,
+						c->map->adc_channel_label);
+		if (chans[mapind].channel == NULL) {
+			ret = -EINVAL;
+			put_device(&chans[mapind].indio_dev->dev);
+			goto error_free_chans;
+		}
+		get_device(&chans[mapind].indio_dev->dev);
+		mapind++;
+	}
+	mutex_unlock(&iio_map_list_lock);
+	if (mapind == 0) {
+		ret = -ENODEV;
+		goto error_free_chans;
+	}
+	return chans;
+
+error_free_chans:
+	for (i = 0; i < nummaps; i++)
+		if (chans[i].indio_dev)
+			put_device(&chans[i].indio_dev->dev);
+	kfree(chans);
+error_ret:
+	mutex_unlock(&iio_map_list_lock);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(iio_st_channel_get_all);
+
+void iio_st_channel_release_all(struct iio_channel *channels)
+{
+	struct iio_channel *chan = &channels[0];
+
+	while (chan->indio_dev) {
+		put_device(&chan->indio_dev->dev);
+		chan++;
+	}
+	kfree(channels);
+}
+EXPORT_SYMBOL_GPL(iio_st_channel_release_all);
+
+int iio_st_read_channel_raw(struct iio_channel *chan, int *val)
+{
+	int val2, ret;
+
+	mutex_lock(&chan->indio_dev->info_exist_lock);
+	if (chan->indio_dev->info == NULL) {
+		ret = -ENODEV;
+		goto err_unlock;
+	}
+
+	ret = chan->indio_dev->info->read_raw(chan->indio_dev, chan->channel,
+					      val, &val2, 0);
+err_unlock:
+	mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_st_read_channel_raw);
+
+int iio_st_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
+{
+	int ret;
+
+	mutex_lock(&chan->indio_dev->info_exist_lock);
+	if (chan->indio_dev->info == NULL) {
+		ret = -ENODEV;
+		goto err_unlock;
+	}
+
+	ret = chan->indio_dev->info->read_raw(chan->indio_dev,
+					      chan->channel,
+					      val, val2,
+					      IIO_CHAN_INFO_SCALE);
+err_unlock:
+	mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_st_read_channel_scale);
+
+int iio_st_get_channel_type(struct iio_channel *chan,
+			    enum iio_chan_type *type)
+{
+	int ret = 0;
+	/* Need to verify underlying driver has not gone away */
+
+	mutex_lock(&chan->indio_dev->info_exist_lock);
+	if (chan->indio_dev->info == NULL) {
+		ret = -ENODEV;
+		goto err_unlock;
+	}
+
+	*type = chan->channel->type;
+err_unlock:
+	mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_st_get_channel_type);
diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
new file mode 100644
index 00000000000..6bf9d05f484
--- /dev/null
+++ b/drivers/iio/kfifo_buf.c
@@ -0,0 +1,150 @@
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/workqueue.h>
+#include <linux/kfifo.h>
+#include <linux/mutex.h>
+#include <linux/iio/kfifo_buf.h>
+
+struct iio_kfifo {
+	struct iio_buffer buffer;
+	struct kfifo kf;
+	int update_needed;
+};
+
+#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
+
+static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
+				int bytes_per_datum, int length)
+{
+	if ((length == 0) || (bytes_per_datum == 0))
+		return -EINVAL;
+
+	__iio_update_buffer(&buf->buffer, bytes_per_datum, length);
+	return kfifo_alloc(&buf->kf, bytes_per_datum*length, GFP_KERNEL);
+}
+
+static int iio_request_update_kfifo(struct iio_buffer *r)
+{
+	int ret = 0;
+	struct iio_kfifo *buf = iio_to_kfifo(r);
+
+	if (!buf->update_needed)
+		goto error_ret;
+	kfifo_free(&buf->kf);
+	ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
+				   buf->buffer.length);
+error_ret:
+	return ret;
+}
+
+static int iio_get_length_kfifo(struct iio_buffer *r)
+{
+	return r->length;
+}
+
+static IIO_BUFFER_ENABLE_ATTR;
+static IIO_BUFFER_LENGTH_ATTR;
+
+static struct attribute *iio_kfifo_attributes[] = {
+	&dev_attr_length.attr,
+	&dev_attr_enable.attr,
+	NULL,
+};
+
+static struct attribute_group iio_kfifo_attribute_group = {
+	.attrs = iio_kfifo_attributes,
+	.name = "buffer",
+};
+
+static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r)
+{
+	return r->bytes_per_datum;
+}
+
+static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
+{
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+	kf->update_needed = true;
+	return 0;
+}
+
+static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
+{
+	if (r->bytes_per_datum != bpd) {
+		r->bytes_per_datum = bpd;
+		iio_mark_update_needed_kfifo(r);
+	}
+	return 0;
+}
+
+static int iio_set_length_kfifo(struct iio_buffer *r, int length)
+{
+	if (r->length != length) {
+		r->length = length;
+		iio_mark_update_needed_kfifo(r);
+	}
+	return 0;
+}
+
+static int iio_store_to_kfifo(struct iio_buffer *r,
+			      u8 *data,
+			      s64 timestamp)
+{
+	int ret;
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+	ret = kfifo_in(&kf->kf, data, r->bytes_per_datum);
+	if (ret != r->bytes_per_datum)
+		return -EBUSY;
+	return 0;
+}
+
+static int iio_read_first_n_kfifo(struct iio_buffer *r,
+			   size_t n, char __user *buf)
+{
+	int ret, copied;
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+
+	if (n < r->bytes_per_datum)
+		return -EINVAL;
+
+	n = rounddown(n, r->bytes_per_datum);
+	ret = kfifo_to_user(&kf->kf, buf, n, &copied);
+
+	return copied;
+}
+
+static const struct iio_buffer_access_funcs kfifo_access_funcs = {
+	.store_to = &iio_store_to_kfifo,
+	.read_first_n = &iio_read_first_n_kfifo,
+	.request_update = &iio_request_update_kfifo,
+	.get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
+	.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
+	.get_length = &iio_get_length_kfifo,
+	.set_length = &iio_set_length_kfifo,
+};
+
+struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
+{
+	struct iio_kfifo *kf;
+
+	kf = kzalloc(sizeof *kf, GFP_KERNEL);
+	if (!kf)
+		return NULL;
+	kf->update_needed = true;
+	iio_buffer_init(&kf->buffer);
+	kf->buffer.attrs = &iio_kfifo_attribute_group;
+	kf->buffer.access = &kfifo_access_funcs;
+
+	return &kf->buffer;
+}
+EXPORT_SYMBOL(iio_kfifo_allocate);
+
+void iio_kfifo_free(struct iio_buffer *r)
+{
+	kfree(iio_to_kfifo(r));
+}
+EXPORT_SYMBOL(iio_kfifo_free);
+
+MODULE_LICENSE("GPL");