Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 2143 insertions, 0 deletions

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
new file mode 100644
index 000000000..c9614982c
--- /dev/null
+++ b/drivers/iio/industrialio-core.c
@@ -0,0 +1,2143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* The industrial I/O core
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ *
+ * Based on elements of hwmon and input subsystems.
+ */
+
+#define pr_fmt(fmt) "iio-core: " fmt
+
+#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/property.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/mutex.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/iio-opaque.h>
+#include "iio_core.h"
+#include "iio_core_trigger.h"
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/buffer_impl.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",
+	[IIO_ALTVOLTAGE] = "altvoltage",
+	[IIO_CCT] = "cct",
+	[IIO_PRESSURE] = "pressure",
+	[IIO_HUMIDITYRELATIVE] = "humidityrelative",
+	[IIO_ACTIVITY] = "activity",
+	[IIO_STEPS] = "steps",
+	[IIO_ENERGY] = "energy",
+	[IIO_DISTANCE] = "distance",
+	[IIO_VELOCITY] = "velocity",
+	[IIO_CONCENTRATION] = "concentration",
+	[IIO_RESISTANCE] = "resistance",
+	[IIO_PH] = "ph",
+	[IIO_UVINDEX] = "uvindex",
+	[IIO_ELECTRICALCONDUCTIVITY] = "electricalconductivity",
+	[IIO_COUNT] = "count",
+	[IIO_INDEX] = "index",
+	[IIO_GRAVITY]  = "gravity",
+	[IIO_POSITIONRELATIVE]  = "positionrelative",
+	[IIO_PHASE] = "phase",
+	[IIO_MASSCONCENTRATION] = "massconcentration",
+};
+
+static const char * const iio_modifier_names[] = {
+	[IIO_MOD_X] = "x",
+	[IIO_MOD_Y] = "y",
+	[IIO_MOD_Z] = "z",
+	[IIO_MOD_X_AND_Y] = "x&y",
+	[IIO_MOD_X_AND_Z] = "x&z",
+	[IIO_MOD_Y_AND_Z] = "y&z",
+	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
+	[IIO_MOD_X_OR_Y] = "x|y",
+	[IIO_MOD_X_OR_Z] = "x|z",
+	[IIO_MOD_Y_OR_Z] = "y|z",
+	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
+	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
+	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
+	[IIO_MOD_LIGHT_BOTH] = "both",
+	[IIO_MOD_LIGHT_IR] = "ir",
+	[IIO_MOD_LIGHT_CLEAR] = "clear",
+	[IIO_MOD_LIGHT_RED] = "red",
+	[IIO_MOD_LIGHT_GREEN] = "green",
+	[IIO_MOD_LIGHT_BLUE] = "blue",
+	[IIO_MOD_LIGHT_UV] = "uv",
+	[IIO_MOD_LIGHT_DUV] = "duv",
+	[IIO_MOD_QUATERNION] = "quaternion",
+	[IIO_MOD_TEMP_AMBIENT] = "ambient",
+	[IIO_MOD_TEMP_OBJECT] = "object",
+	[IIO_MOD_NORTH_MAGN] = "from_north_magnetic",
+	[IIO_MOD_NORTH_TRUE] = "from_north_true",
+	[IIO_MOD_NORTH_MAGN_TILT_COMP] = "from_north_magnetic_tilt_comp",
+	[IIO_MOD_NORTH_TRUE_TILT_COMP] = "from_north_true_tilt_comp",
+	[IIO_MOD_RUNNING] = "running",
+	[IIO_MOD_JOGGING] = "jogging",
+	[IIO_MOD_WALKING] = "walking",
+	[IIO_MOD_STILL] = "still",
+	[IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
+	[IIO_MOD_I] = "i",
+	[IIO_MOD_Q] = "q",
+	[IIO_MOD_CO2] = "co2",
+	[IIO_MOD_VOC] = "voc",
+	[IIO_MOD_PM1] = "pm1",
+	[IIO_MOD_PM2P5] = "pm2p5",
+	[IIO_MOD_PM4] = "pm4",
+	[IIO_MOD_PM10] = "pm10",
+	[IIO_MOD_ETHANOL] = "ethanol",
+	[IIO_MOD_H2] = "h2",
+	[IIO_MOD_O2] = "o2",
+	[IIO_MOD_LINEAR_X] = "linear_x",
+	[IIO_MOD_LINEAR_Y] = "linear_y",
+	[IIO_MOD_LINEAR_Z] = "linear_z",
+	[IIO_MOD_PITCH] = "pitch",
+	[IIO_MOD_YAW] = "yaw",
+	[IIO_MOD_ROLL] = "roll",
+};
+
+/* 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_HIGH_PASS_FILTER_3DB_FREQUENCY]
+	= "filter_high_pass_3db_frequency",
+	[IIO_CHAN_INFO_SAMP_FREQ] = "sampling_frequency",
+	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
+	[IIO_CHAN_INFO_PHASE] = "phase",
+	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
+	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
+	[IIO_CHAN_INFO_HYSTERESIS_RELATIVE] = "hysteresis_relative",
+	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
+	[IIO_CHAN_INFO_ENABLE] = "en",
+	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
+	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
+	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
+	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
+	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
+	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
+	[IIO_CHAN_INFO_THERMOCOUPLE_TYPE] = "thermocouple_type",
+	[IIO_CHAN_INFO_CALIBAMBIENT] = "calibambient",
+	[IIO_CHAN_INFO_ZEROPOINT] = "zeropoint",
+};
+/**
+ * iio_device_id() - query the unique ID for the device
+ * @indio_dev:		Device structure whose ID is being queried
+ *
+ * The IIO device ID is a unique index used for example for the naming
+ * of the character device /dev/iio\:device[ID]
+ */
+int iio_device_id(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	return iio_dev_opaque->id;
+}
+EXPORT_SYMBOL_GPL(iio_device_id);
+
+/**
+ * iio_buffer_enabled() - helper function to test if the buffer is enabled
+ * @indio_dev:		IIO device structure for device
+ */
+bool iio_buffer_enabled(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	return iio_dev_opaque->currentmode
+		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE |
+		   INDIO_BUFFER_SOFTWARE);
+}
+EXPORT_SYMBOL_GPL(iio_buffer_enabled);
+
+/**
+ * iio_sysfs_match_string_with_gaps - matches given string in an array with gaps
+ * @array: array of strings
+ * @n: number of strings in the array
+ * @str: string to match with
+ *
+ * Returns index of @str in the @array or -EINVAL, similar to match_string().
+ * Uses sysfs_streq instead of strcmp for matching.
+ *
+ * This routine will look for a string in an array of strings.
+ * The search will continue until the element is found or the n-th element
+ * is reached, regardless of any NULL elements in the array.
+ */
+static int iio_sysfs_match_string_with_gaps(const char * const *array, size_t n,
+					    const char *str)
+{
+	const char *item;
+	int index;
+
+	for (index = 0; index < n; index++) {
+		item = array[index];
+		if (!item)
+			continue;
+		if (sysfs_streq(item, str))
+			return index;
+	}
+
+	return -EINVAL;
+}
+
+#if defined(CONFIG_DEBUG_FS)
+/*
+ * There's also a CONFIG_DEBUG_FS guard in include/linux/iio/iio.h for
+ * iio_get_debugfs_dentry() to make it inline if CONFIG_DEBUG_FS is undefined
+ */
+struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	return iio_dev_opaque->debugfs_dentry;
+}
+EXPORT_SYMBOL_GPL(iio_get_debugfs_dentry);
+#endif
+
+/**
+ * iio_find_channel_from_si() - get channel from its scan index
+ * @indio_dev:		device
+ * @si:			scan index to match
+ */
+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 sysfs_emit(buf, "%s\n", to_iio_const_attr(attr)->string);
+}
+EXPORT_SYMBOL(iio_read_const_attr);
+
+/**
+ * iio_device_set_clock() - Set current timestamping clock for the device
+ * @indio_dev: IIO device structure containing the device
+ * @clock_id: timestamping clock posix identifier to set.
+ */
+int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
+{
+	int ret;
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	const struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
+
+	ret = mutex_lock_interruptible(&indio_dev->mlock);
+	if (ret)
+		return ret;
+	if ((ev_int && iio_event_enabled(ev_int)) ||
+	    iio_buffer_enabled(indio_dev)) {
+		mutex_unlock(&indio_dev->mlock);
+		return -EBUSY;
+	}
+	iio_dev_opaque->clock_id = clock_id;
+	mutex_unlock(&indio_dev->mlock);
+
+	return 0;
+}
+EXPORT_SYMBOL(iio_device_set_clock);
+
+/**
+ * iio_device_get_clock() - Retrieve current timestamping clock for the device
+ * @indio_dev: IIO device structure containing the device
+ */
+clockid_t iio_device_get_clock(const struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	return iio_dev_opaque->clock_id;
+}
+EXPORT_SYMBOL(iio_device_get_clock);
+
+/**
+ * iio_get_time_ns() - utility function to get a time stamp for events etc
+ * @indio_dev: device
+ */
+s64 iio_get_time_ns(const struct iio_dev *indio_dev)
+{
+	struct timespec64 tp;
+
+	switch (iio_device_get_clock(indio_dev)) {
+	case CLOCK_REALTIME:
+		return ktime_get_real_ns();
+	case CLOCK_MONOTONIC:
+		return ktime_get_ns();
+	case CLOCK_MONOTONIC_RAW:
+		return ktime_get_raw_ns();
+	case CLOCK_REALTIME_COARSE:
+		return ktime_to_ns(ktime_get_coarse_real());
+	case CLOCK_MONOTONIC_COARSE:
+		ktime_get_coarse_ts64(&tp);
+		return timespec64_to_ns(&tp);
+	case CLOCK_BOOTTIME:
+		return ktime_get_boottime_ns();
+	case CLOCK_TAI:
+		return ktime_get_clocktai_ns();
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL(iio_get_time_ns);
+
+static int __init iio_init(void)
+{
+	int ret;
+
+	/* Register sysfs bus */
+	ret  = bus_register(&iio_bus_type);
+	if (ret < 0) {
+		pr_err("could not register bus type\n");
+		goto error_nothing;
+	}
+
+	ret = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
+	if (ret < 0) {
+		pr_err("failed to allocate char dev region\n");
+		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 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;
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	unsigned int val = 0;
+	int ret;
+
+	if (*ppos > 0)
+		return simple_read_from_buffer(userbuf, count, ppos,
+					       iio_dev_opaque->read_buf,
+					       iio_dev_opaque->read_buf_len);
+
+	ret = indio_dev->info->debugfs_reg_access(indio_dev,
+						  iio_dev_opaque->cached_reg_addr,
+						  0, &val);
+	if (ret) {
+		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
+		return ret;
+	}
+
+	iio_dev_opaque->read_buf_len = snprintf(iio_dev_opaque->read_buf,
+					      sizeof(iio_dev_opaque->read_buf),
+					      "0x%X\n", val);
+
+	return simple_read_from_buffer(userbuf, count, ppos,
+				       iio_dev_opaque->read_buf,
+				       iio_dev_opaque->read_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;
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	unsigned int 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:
+		iio_dev_opaque->cached_reg_addr = reg;
+		break;
+	case 2:
+		iio_dev_opaque->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 = simple_open,
+	.read = iio_debugfs_read_reg,
+	.write = iio_debugfs_write_reg,
+};
+
+static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	debugfs_remove_recursive(iio_dev_opaque->debugfs_dentry);
+}
+
+static void iio_device_register_debugfs(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque;
+
+	if (indio_dev->info->debugfs_reg_access == NULL)
+		return;
+
+	if (!iio_debugfs_dentry)
+		return;
+
+	iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	iio_dev_opaque->debugfs_dentry =
+		debugfs_create_dir(dev_name(&indio_dev->dev),
+				   iio_debugfs_dentry);
+
+	debugfs_create_file("direct_reg_access", 0644,
+			    iio_dev_opaque->debugfs_dentry, indio_dev,
+			    &iio_debugfs_reg_fops);
+}
+#else
+static void iio_device_register_debugfs(struct iio_dev *indio_dev)
+{
+}
+
+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_to_iio_dev(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, ext_info->private, 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_to_iio_dev(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, ext_info->private,
+			       this_attr->c, buf, len);
+}
+
+ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
+	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
+{
+	const struct iio_enum *e = (const struct iio_enum *)priv;
+	unsigned int i;
+	size_t len = 0;
+
+	if (!e->num_items)
+		return 0;
+
+	for (i = 0; i < e->num_items; ++i) {
+		if (!e->items[i])
+			continue;
+		len += sysfs_emit_at(buf, len, "%s ", e->items[i]);
+	}
+
+	/* replace last space with a newline */
+	buf[len - 1] = '\n';
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(iio_enum_available_read);
+
+ssize_t iio_enum_read(struct iio_dev *indio_dev,
+	uintptr_t priv, const struct iio_chan_spec *chan, char *buf)
+{
+	const struct iio_enum *e = (const struct iio_enum *)priv;
+	int i;
+
+	if (!e->get)
+		return -EINVAL;
+
+	i = e->get(indio_dev, chan);
+	if (i < 0)
+		return i;
+	else if (i >= e->num_items || !e->items[i])
+		return -EINVAL;
+
+	return sysfs_emit(buf, "%s\n", e->items[i]);
+}
+EXPORT_SYMBOL_GPL(iio_enum_read);
+
+ssize_t iio_enum_write(struct iio_dev *indio_dev,
+	uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
+	size_t len)
+{
+	const struct iio_enum *e = (const struct iio_enum *)priv;
+	int ret;
+
+	if (!e->set)
+		return -EINVAL;
+
+	ret = iio_sysfs_match_string_with_gaps(e->items, e->num_items, buf);
+	if (ret < 0)
+		return ret;
+
+	ret = e->set(indio_dev, chan, ret);
+	return ret ? ret : len;
+}
+EXPORT_SYMBOL_GPL(iio_enum_write);
+
+static const struct iio_mount_matrix iio_mount_idmatrix = {
+	.rotation = {
+		"1", "0", "0",
+		"0", "1", "0",
+		"0", "0", "1"
+	}
+};
+
+static int iio_setup_mount_idmatrix(const struct device *dev,
+				    struct iio_mount_matrix *matrix)
+{
+	*matrix = iio_mount_idmatrix;
+	dev_info(dev, "mounting matrix not found: using identity...\n");
+	return 0;
+}
+
+ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
+			      const struct iio_chan_spec *chan, char *buf)
+{
+	const struct iio_mount_matrix *mtx = ((iio_get_mount_matrix_t *)
+					      priv)(indio_dev, chan);
+
+	if (IS_ERR(mtx))
+		return PTR_ERR(mtx);
+
+	if (!mtx)
+		mtx = &iio_mount_idmatrix;
+
+	return sysfs_emit(buf, "%s, %s, %s; %s, %s, %s; %s, %s, %s\n",
+			  mtx->rotation[0], mtx->rotation[1], mtx->rotation[2],
+			  mtx->rotation[3], mtx->rotation[4], mtx->rotation[5],
+			  mtx->rotation[6], mtx->rotation[7], mtx->rotation[8]);
+}
+EXPORT_SYMBOL_GPL(iio_show_mount_matrix);
+
+/**
+ * iio_read_mount_matrix() - retrieve iio device mounting matrix from
+ *                           device "mount-matrix" property
+ * @dev:	device the mounting matrix property is assigned to
+ * @matrix:	where to store retrieved matrix
+ *
+ * If device is assigned no mounting matrix property, a default 3x3 identity
+ * matrix will be filled in.
+ *
+ * Return: 0 if success, or a negative error code on failure.
+ */
+int iio_read_mount_matrix(struct device *dev, struct iio_mount_matrix *matrix)
+{
+	size_t len = ARRAY_SIZE(iio_mount_idmatrix.rotation);
+	int err;
+
+	err = device_property_read_string_array(dev, "mount-matrix", matrix->rotation, len);
+	if (err == len)
+		return 0;
+
+	if (err >= 0)
+		/* Invalid number of matrix entries. */
+		return -EINVAL;
+
+	if (err != -EINVAL)
+		/* Invalid matrix declaration format. */
+		return err;
+
+	/* Matrix was not declared at all: fallback to identity. */
+	return iio_setup_mount_idmatrix(dev, matrix);
+}
+EXPORT_SYMBOL(iio_read_mount_matrix);
+
+static ssize_t __iio_format_value(char *buf, size_t offset, unsigned int type,
+				  int size, const int *vals)
+{
+	int tmp0, tmp1;
+	s64 tmp2;
+	bool scale_db = false;
+
+	switch (type) {
+	case IIO_VAL_INT:
+		return sysfs_emit_at(buf, offset, "%d", vals[0]);
+	case IIO_VAL_INT_PLUS_MICRO_DB:
+		scale_db = true;
+		fallthrough;
+	case IIO_VAL_INT_PLUS_MICRO:
+		if (vals[1] < 0)
+			return sysfs_emit_at(buf, offset, "-%d.%06u%s",
+					     abs(vals[0]), -vals[1],
+					     scale_db ? " dB" : "");
+		else
+			return sysfs_emit_at(buf, offset, "%d.%06u%s", vals[0],
+					     vals[1], scale_db ? " dB" : "");
+	case IIO_VAL_INT_PLUS_NANO:
+		if (vals[1] < 0)
+			return sysfs_emit_at(buf, offset, "-%d.%09u",
+					     abs(vals[0]), -vals[1]);
+		else
+			return sysfs_emit_at(buf, offset, "%d.%09u", vals[0],
+					     vals[1]);
+	case IIO_VAL_FRACTIONAL:
+		tmp2 = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
+		tmp1 = vals[1];
+		tmp0 = (int)div_s64_rem(tmp2, 1000000000, &tmp1);
+		if ((tmp2 < 0) && (tmp0 == 0))
+			return sysfs_emit_at(buf, offset, "-0.%09u", abs(tmp1));
+		else
+			return sysfs_emit_at(buf, offset, "%d.%09u", tmp0,
+					     abs(tmp1));
+	case IIO_VAL_FRACTIONAL_LOG2:
+		tmp2 = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
+		tmp0 = (int)div_s64_rem(tmp2, 1000000000LL, &tmp1);
+		if (tmp0 == 0 && tmp2 < 0)
+			return sysfs_emit_at(buf, offset, "-0.%09u", abs(tmp1));
+		else
+			return sysfs_emit_at(buf, offset, "%d.%09u", tmp0,
+					     abs(tmp1));
+	case IIO_VAL_INT_MULTIPLE:
+	{
+		int i;
+		int l = 0;
+
+		for (i = 0; i < size; ++i)
+			l += sysfs_emit_at(buf, offset + l, "%d ", vals[i]);
+		return l;
+	}
+	case IIO_VAL_CHAR:
+		return sysfs_emit_at(buf, offset, "%c", (char)vals[0]);
+	case IIO_VAL_INT_64:
+		tmp2 = (s64)((((u64)vals[1]) << 32) | (u32)vals[0]);
+		return sysfs_emit_at(buf, offset, "%lld", tmp2);
+	default:
+		return 0;
+	}
+}
+
+/**
+ * iio_format_value() - Formats a IIO value into its string representation
+ * @buf:	The buffer to which the formatted value gets written
+ *		which is assumed to be big enough (i.e. PAGE_SIZE).
+ * @type:	One of the IIO_VAL_* constants. This decides how the val
+ *		and val2 parameters are formatted.
+ * @size:	Number of IIO value entries contained in vals
+ * @vals:	Pointer to the values, exact meaning depends on the
+ *		type parameter.
+ *
+ * Return: 0 by default, a negative number on failure or the
+ *	   total number of characters written for a type that belongs
+ *	   to the IIO_VAL_* constant.
+ */
+ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
+{
+	ssize_t len;
+
+	len = __iio_format_value(buf, 0, type, size, vals);
+	if (len >= PAGE_SIZE - 1)
+		return -EFBIG;
+
+	return len + sysfs_emit_at(buf, len, "\n");
+}
+EXPORT_SYMBOL_GPL(iio_format_value);
+
+static ssize_t iio_read_channel_label(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	if (indio_dev->info->read_label)
+		return indio_dev->info->read_label(indio_dev, this_attr->c, buf);
+
+	if (this_attr->c->extend_name)
+		return sysfs_emit(buf, "%s\n", this_attr->c->extend_name);
+
+	return -EINVAL;
+}
+
+static ssize_t iio_read_channel_info(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int vals[INDIO_MAX_RAW_ELEMENTS];
+	int ret;
+	int val_len = 2;
+
+	if (indio_dev->info->read_raw_multi)
+		ret = indio_dev->info->read_raw_multi(indio_dev, this_attr->c,
+							INDIO_MAX_RAW_ELEMENTS,
+							vals, &val_len,
+							this_attr->address);
+	else
+		ret = indio_dev->info->read_raw(indio_dev, this_attr->c,
+				    &vals[0], &vals[1], this_attr->address);
+
+	if (ret < 0)
+		return ret;
+
+	return iio_format_value(buf, ret, val_len, vals);
+}
+
+static ssize_t iio_format_list(char *buf, const int *vals, int type, int length,
+			       const char *prefix, const char *suffix)
+{
+	ssize_t len;
+	int stride;
+	int i;
+
+	switch (type) {
+	case IIO_VAL_INT:
+		stride = 1;
+		break;
+	default:
+		stride = 2;
+		break;
+	}
+
+	len = sysfs_emit(buf, prefix);
+
+	for (i = 0; i <= length - stride; i += stride) {
+		if (i != 0) {
+			len += sysfs_emit_at(buf, len, " ");
+			if (len >= PAGE_SIZE)
+				return -EFBIG;
+		}
+
+		len += __iio_format_value(buf, len, type, stride, &vals[i]);
+		if (len >= PAGE_SIZE)
+			return -EFBIG;
+	}
+
+	len += sysfs_emit_at(buf, len, "%s\n", suffix);
+
+	return len;
+}
+
+static ssize_t iio_format_avail_list(char *buf, const int *vals,
+				     int type, int length)
+{
+
+	return iio_format_list(buf, vals, type, length, "", "");
+}
+
+static ssize_t iio_format_avail_range(char *buf, const int *vals, int type)
+{
+	int length;
+
+	/*
+	 * length refers to the array size , not the number of elements.
+	 * The purpose is to print the range [min , step ,max] so length should
+	 * be 3 in case of int, and 6 for other types.
+	 */
+	switch (type) {
+	case IIO_VAL_INT:
+		length = 3;
+		break;
+	default:
+		length = 6;
+		break;
+	}
+
+	return iio_format_list(buf, vals, type, length, "[", "]");
+}
+
+static ssize_t iio_read_channel_info_avail(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	const int *vals;
+	int ret;
+	int length;
+	int type;
+
+	ret = indio_dev->info->read_avail(indio_dev, this_attr->c,
+					  &vals, &type, &length,
+					  this_attr->address);
+
+	if (ret < 0)
+		return ret;
+	switch (ret) {
+	case IIO_AVAIL_LIST:
+		return iio_format_avail_list(buf, vals, type, length);
+	case IIO_AVAIL_RANGE:
+		return iio_format_avail_range(buf, vals, type);
+	default:
+		return -EINVAL;
+	}
+}
+
+/**
+ * __iio_str_to_fixpoint() - Parse a fixed-point number from a string
+ * @str: The string to parse
+ * @fract_mult: Multiplier for the first decimal place, should be a power of 10
+ * @integer: The integer part of the number
+ * @fract: The fractional part of the number
+ * @scale_db: True if this should parse as dB
+ *
+ * Returns 0 on success, or a negative error code if the string could not be
+ * parsed.
+ */
+static int __iio_str_to_fixpoint(const char *str, int fract_mult,
+				 int *integer, int *fract, bool scale_db)
+{
+	int i = 0, f = 0;
+	bool integer_part = true, negative = false;
+
+	if (fract_mult == 0) {
+		*fract = 0;
+
+		return kstrtoint(str, 0, integer);
+	}
+
+	if (str[0] == '-') {
+		negative = true;
+		str++;
+	} else if (str[0] == '+') {
+		str++;
+	}
+
+	while (*str) {
+		if ('0' <= *str && *str <= '9') {
+			if (integer_part) {
+				i = i * 10 + *str - '0';
+			} else {
+				f += fract_mult * (*str - '0');
+				fract_mult /= 10;
+			}
+		} else if (*str == '\n') {
+			if (*(str + 1) == '\0')
+				break;
+			return -EINVAL;
+		} else if (!strncmp(str, " dB", sizeof(" dB") - 1) && scale_db) {
+			/* Ignore the dB suffix */
+			str += sizeof(" dB") - 1;
+			continue;
+		} else if (!strncmp(str, "dB", sizeof("dB") - 1) && scale_db) {
+			/* Ignore the dB suffix */
+			str += sizeof("dB") - 1;
+			continue;
+		} else if (*str == '.' && integer_part) {
+			integer_part = false;
+		} else {
+			return -EINVAL;
+		}
+		str++;
+	}
+
+	if (negative) {
+		if (i)
+			i = -i;
+		else
+			f = -f;
+	}
+
+	*integer = i;
+	*fract = f;
+
+	return 0;
+}
+
+/**
+ * iio_str_to_fixpoint() - Parse a fixed-point number from a string
+ * @str: The string to parse
+ * @fract_mult: Multiplier for the first decimal place, should be a power of 10
+ * @integer: The integer part of the number
+ * @fract: The fractional part of the number
+ *
+ * Returns 0 on success, or a negative error code if the string could not be
+ * parsed.
+ */
+int iio_str_to_fixpoint(const char *str, int fract_mult,
+			int *integer, int *fract)
+{
+	return __iio_str_to_fixpoint(str, fract_mult, integer, fract, false);
+}
+EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
+
+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_to_iio_dev(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int ret, fract_mult = 100000;
+	int integer, fract = 0;
+	bool is_char = false;
+	bool scale_db = 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:
+			fract_mult = 0;
+			break;
+		case IIO_VAL_INT_PLUS_MICRO_DB:
+			scale_db = true;
+			fallthrough;
+		case IIO_VAL_INT_PLUS_MICRO:
+			fract_mult = 100000;
+			break;
+		case IIO_VAL_INT_PLUS_NANO:
+			fract_mult = 100000000;
+			break;
+		case IIO_VAL_CHAR:
+			is_char = true;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+	if (is_char) {
+		char ch;
+
+		if (sscanf(buf, "%c", &ch) != 1)
+			return -EINVAL;
+		integer = ch;
+	} else {
+		ret = __iio_str_to_fixpoint(buf, fract_mult, &integer, &fract,
+					    scale_db);
+		if (ret)
+			return ret;
+	}
+
+	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),
+			   enum iio_shared_by shared_by)
+{
+	int ret = 0;
+	char *name = NULL;
+	char *full_postfix;
+
+	sysfs_attr_init(&dev_attr->attr);
+
+	/* Build up postfix of <extend_name>_<modifier>_postfix */
+	if (chan->modified && (shared_by == IIO_SEPARATE)) {
+		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 || shared_by != IIO_SEPARATE)
+			full_postfix = kstrdup(postfix, GFP_KERNEL);
+		else
+			full_postfix = kasprintf(GFP_KERNEL,
+						 "%s_%s",
+						 chan->extend_name,
+						 postfix);
+	}
+	if (full_postfix == NULL)
+		return -ENOMEM;
+
+	if (chan->differential) { /* Differential can not have modifier */
+		switch (shared_by) {
+		case IIO_SHARED_BY_ALL:
+			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
+			break;
+		case IIO_SHARED_BY_DIR:
+			name = kasprintf(GFP_KERNEL, "%s_%s",
+						iio_direction[chan->output],
+						full_postfix);
+			break;
+		case IIO_SHARED_BY_TYPE:
+			name = 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);
+			break;
+		case IIO_SEPARATE:
+			if (!chan->indexed) {
+				WARN(1, "Differential channels must be indexed\n");
+				ret = -EINVAL;
+				goto error_free_full_postfix;
+			}
+			name = 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);
+			break;
+		}
+	} else { /* Single ended */
+		switch (shared_by) {
+		case IIO_SHARED_BY_ALL:
+			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
+			break;
+		case IIO_SHARED_BY_DIR:
+			name = kasprintf(GFP_KERNEL, "%s_%s",
+						iio_direction[chan->output],
+						full_postfix);
+			break;
+		case IIO_SHARED_BY_TYPE:
+			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
+					    iio_direction[chan->output],
+					    iio_chan_type_name_spec[chan->type],
+					    full_postfix);
+			break;
+
+		case IIO_SEPARATE:
+			if (chan->indexed)
+				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
+						    iio_direction[chan->output],
+						    iio_chan_type_name_spec[chan->type],
+						    chan->channel,
+						    full_postfix);
+			else
+				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
+						    iio_direction[chan->output],
+						    iio_chan_type_name_spec[chan->type],
+						    full_postfix);
+			break;
+		}
+	}
+	if (name == NULL) {
+		ret = -ENOMEM;
+		goto error_free_full_postfix;
+	}
+	dev_attr->attr.name = name;
+
+	if (readfunc) {
+		dev_attr->attr.mode |= 0444;
+		dev_attr->show = readfunc;
+	}
+
+	if (writefunc) {
+		dev_attr->attr.mode |= 0200;
+		dev_attr->store = writefunc;
+	}
+
+error_free_full_postfix:
+	kfree(full_postfix);
+
+	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,
+			   enum iio_shared_by shared_by,
+			   struct device *dev,
+			   struct iio_buffer *buffer,
+			   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)
+		return -ENOMEM;
+	ret = __iio_device_attr_init(&iio_attr->dev_attr,
+				     postfix, chan,
+				     readfunc, writefunc, shared_by);
+	if (ret)
+		goto error_iio_dev_attr_free;
+	iio_attr->c = chan;
+	iio_attr->address = mask;
+	iio_attr->buffer = buffer;
+	list_for_each_entry(t, attr_list, l)
+		if (strcmp(t->dev_attr.attr.name,
+			   iio_attr->dev_attr.attr.name) == 0) {
+			if (shared_by == IIO_SEPARATE)
+				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);
+	return ret;
+}
+
+static int iio_device_add_channel_label(struct iio_dev *indio_dev,
+					 struct iio_chan_spec const *chan)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	int ret;
+
+	if (!indio_dev->info->read_label && !chan->extend_name)
+		return 0;
+
+	ret = __iio_add_chan_devattr("label",
+				     chan,
+				     &iio_read_channel_label,
+				     NULL,
+				     0,
+				     IIO_SEPARATE,
+				     &indio_dev->dev,
+				     NULL,
+				     &iio_dev_opaque->channel_attr_list);
+	if (ret < 0)
+		return ret;
+
+	return 1;
+}
+
+static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
+					 struct iio_chan_spec const *chan,
+					 enum iio_shared_by shared_by,
+					 const long *infomask)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	int i, ret, attrcount = 0;
+
+	for_each_set_bit(i, infomask, sizeof(*infomask)*8) {
+		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
+			return -EINVAL;
+		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
+					     chan,
+					     &iio_read_channel_info,
+					     &iio_write_channel_info,
+					     i,
+					     shared_by,
+					     &indio_dev->dev,
+					     NULL,
+					     &iio_dev_opaque->channel_attr_list);
+		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
+			continue;
+		else if (ret < 0)
+			return ret;
+		attrcount++;
+	}
+
+	return attrcount;
+}
+
+static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
+					       struct iio_chan_spec const *chan,
+					       enum iio_shared_by shared_by,
+					       const long *infomask)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	int i, ret, attrcount = 0;
+	char *avail_postfix;
+
+	for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
+		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
+			return -EINVAL;
+		avail_postfix = kasprintf(GFP_KERNEL,
+					  "%s_available",
+					  iio_chan_info_postfix[i]);
+		if (!avail_postfix)
+			return -ENOMEM;
+
+		ret = __iio_add_chan_devattr(avail_postfix,
+					     chan,
+					     &iio_read_channel_info_avail,
+					     NULL,
+					     i,
+					     shared_by,
+					     &indio_dev->dev,
+					     NULL,
+					     &iio_dev_opaque->channel_attr_list);
+		kfree(avail_postfix);
+		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
+			continue;
+		else if (ret < 0)
+			return ret;
+		attrcount++;
+	}
+
+	return attrcount;
+}
+
+static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
+					struct iio_chan_spec const *chan)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	int ret, attrcount = 0;
+	const struct iio_chan_spec_ext_info *ext_info;
+
+	if (chan->channel < 0)
+		return 0;
+	ret = iio_device_add_info_mask_type(indio_dev, chan,
+					    IIO_SEPARATE,
+					    &chan->info_mask_separate);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
+						  IIO_SEPARATE,
+						  &chan->info_mask_separate_available);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	ret = iio_device_add_info_mask_type(indio_dev, chan,
+					    IIO_SHARED_BY_TYPE,
+					    &chan->info_mask_shared_by_type);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
+						  IIO_SHARED_BY_TYPE,
+						  &chan->info_mask_shared_by_type_available);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	ret = iio_device_add_info_mask_type(indio_dev, chan,
+					    IIO_SHARED_BY_DIR,
+					    &chan->info_mask_shared_by_dir);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
+						  IIO_SHARED_BY_DIR,
+						  &chan->info_mask_shared_by_dir_available);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	ret = iio_device_add_info_mask_type(indio_dev, chan,
+					    IIO_SHARED_BY_ALL,
+					    &chan->info_mask_shared_by_all);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	ret = iio_device_add_info_mask_type_avail(indio_dev, chan,
+						  IIO_SHARED_BY_ALL,
+						  &chan->info_mask_shared_by_all_available);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	ret = iio_device_add_channel_label(indio_dev, chan);
+	if (ret < 0)
+		return ret;
+	attrcount += ret;
+
+	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,
+					NULL,
+					&iio_dev_opaque->channel_attr_list);
+			i++;
+			if (ret == -EBUSY && ext_info->shared)
+				continue;
+
+			if (ret)
+				return ret;
+
+			attrcount++;
+		}
+	}
+
+	return attrcount;
+}
+
+/**
+ * iio_free_chan_devattr_list() - Free a list of IIO device attributes
+ * @attr_list: List of IIO device attributes
+ *
+ * This function frees the memory allocated for each of the IIO device
+ * attributes in the list.
+ */
+void iio_free_chan_devattr_list(struct list_head *attr_list)
+{
+	struct iio_dev_attr *p, *n;
+
+	list_for_each_entry_safe(p, n, attr_list, l) {
+		kfree_const(p->dev_attr.attr.name);
+		list_del(&p->l);
+		kfree(p);
+	}
+}
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+
+	return sysfs_emit(buf, "%s\n", indio_dev->name);
+}
+
+static DEVICE_ATTR_RO(name);
+
+static ssize_t label_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+
+	return sysfs_emit(buf, "%s\n", indio_dev->label);
+}
+
+static DEVICE_ATTR_RO(label);
+
+static ssize_t current_timestamp_clock_show(struct device *dev,
+					    struct device_attribute *attr,
+					    char *buf)
+{
+	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	const clockid_t clk = iio_device_get_clock(indio_dev);
+	const char *name;
+	ssize_t sz;
+
+	switch (clk) {
+	case CLOCK_REALTIME:
+		name = "realtime\n";
+		sz = sizeof("realtime\n");
+		break;
+	case CLOCK_MONOTONIC:
+		name = "monotonic\n";
+		sz = sizeof("monotonic\n");
+		break;
+	case CLOCK_MONOTONIC_RAW:
+		name = "monotonic_raw\n";
+		sz = sizeof("monotonic_raw\n");
+		break;
+	case CLOCK_REALTIME_COARSE:
+		name = "realtime_coarse\n";
+		sz = sizeof("realtime_coarse\n");
+		break;
+	case CLOCK_MONOTONIC_COARSE:
+		name = "monotonic_coarse\n";
+		sz = sizeof("monotonic_coarse\n");
+		break;
+	case CLOCK_BOOTTIME:
+		name = "boottime\n";
+		sz = sizeof("boottime\n");
+		break;
+	case CLOCK_TAI:
+		name = "tai\n";
+		sz = sizeof("tai\n");
+		break;
+	default:
+		BUG();
+	}
+
+	memcpy(buf, name, sz);
+	return sz;
+}
+
+static ssize_t current_timestamp_clock_store(struct device *dev,
+					     struct device_attribute *attr,
+					     const char *buf, size_t len)
+{
+	clockid_t clk;
+	int ret;
+
+	if (sysfs_streq(buf, "realtime"))
+		clk = CLOCK_REALTIME;
+	else if (sysfs_streq(buf, "monotonic"))
+		clk = CLOCK_MONOTONIC;
+	else if (sysfs_streq(buf, "monotonic_raw"))
+		clk = CLOCK_MONOTONIC_RAW;
+	else if (sysfs_streq(buf, "realtime_coarse"))
+		clk = CLOCK_REALTIME_COARSE;
+	else if (sysfs_streq(buf, "monotonic_coarse"))
+		clk = CLOCK_MONOTONIC_COARSE;
+	else if (sysfs_streq(buf, "boottime"))
+		clk = CLOCK_BOOTTIME;
+	else if (sysfs_streq(buf, "tai"))
+		clk = CLOCK_TAI;
+	else
+		return -EINVAL;
+
+	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
+	if (ret)
+		return ret;
+
+	return len;
+}
+
+int iio_device_register_sysfs_group(struct iio_dev *indio_dev,
+				    const struct attribute_group *group)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	const struct attribute_group **new, **old = iio_dev_opaque->groups;
+	unsigned int cnt = iio_dev_opaque->groupcounter;
+
+	new = krealloc(old, sizeof(*new) * (cnt + 2), GFP_KERNEL);
+	if (!new)
+		return -ENOMEM;
+
+	new[iio_dev_opaque->groupcounter++] = group;
+	new[iio_dev_opaque->groupcounter] = NULL;
+
+	iio_dev_opaque->groups = new;
+
+	return 0;
+}
+
+static DEVICE_ATTR_RW(current_timestamp_clock);
+
+static int iio_device_register_sysfs(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
+	struct iio_dev_attr *p;
+	struct attribute **attr, *clk = NULL;
+
+	/* 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 its name is NULL.
+	 */
+	if (indio_dev->channels)
+		for (i = 0; i < indio_dev->num_channels; i++) {
+			const struct iio_chan_spec *chan =
+				&indio_dev->channels[i];
+
+			if (chan->type == IIO_TIMESTAMP)
+				clk = &dev_attr_current_timestamp_clock.attr;
+
+			ret = iio_device_add_channel_sysfs(indio_dev, chan);
+			if (ret < 0)
+				goto error_clear_attrs;
+			attrcount += ret;
+		}
+
+	if (iio_dev_opaque->event_interface)
+		clk = &dev_attr_current_timestamp_clock.attr;
+
+	if (indio_dev->name)
+		attrcount++;
+	if (indio_dev->label)
+		attrcount++;
+	if (clk)
+		attrcount++;
+
+	iio_dev_opaque->chan_attr_group.attrs =
+		kcalloc(attrcount + 1,
+			sizeof(iio_dev_opaque->chan_attr_group.attrs[0]),
+			GFP_KERNEL);
+	if (iio_dev_opaque->chan_attr_group.attrs == NULL) {
+		ret = -ENOMEM;
+		goto error_clear_attrs;
+	}
+	/* Copy across original attributes, and point to original binary attributes */
+	if (indio_dev->info->attrs) {
+		memcpy(iio_dev_opaque->chan_attr_group.attrs,
+		       indio_dev->info->attrs->attrs,
+		       sizeof(iio_dev_opaque->chan_attr_group.attrs[0])
+		       *attrcount_orig);
+		iio_dev_opaque->chan_attr_group.is_visible =
+			indio_dev->info->attrs->is_visible;
+		iio_dev_opaque->chan_attr_group.bin_attrs =
+			indio_dev->info->attrs->bin_attrs;
+	}
+	attrn = attrcount_orig;
+	/* Add all elements from the list. */
+	list_for_each_entry(p, &iio_dev_opaque->channel_attr_list, l)
+		iio_dev_opaque->chan_attr_group.attrs[attrn++] = &p->dev_attr.attr;
+	if (indio_dev->name)
+		iio_dev_opaque->chan_attr_group.attrs[attrn++] = &dev_attr_name.attr;
+	if (indio_dev->label)
+		iio_dev_opaque->chan_attr_group.attrs[attrn++] = &dev_attr_label.attr;
+	if (clk)
+		iio_dev_opaque->chan_attr_group.attrs[attrn++] = clk;
+
+	ret = iio_device_register_sysfs_group(indio_dev,
+					      &iio_dev_opaque->chan_attr_group);
+	if (ret)
+		goto error_clear_attrs;
+
+	return 0;
+
+error_clear_attrs:
+	iio_free_chan_devattr_list(&iio_dev_opaque->channel_attr_list);
+
+	return ret;
+}
+
+static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	iio_free_chan_devattr_list(&iio_dev_opaque->channel_attr_list);
+	kfree(iio_dev_opaque->chan_attr_group.attrs);
+	iio_dev_opaque->chan_attr_group.attrs = NULL;
+	kfree(iio_dev_opaque->groups);
+	iio_dev_opaque->groups = NULL;
+}
+
+static void iio_dev_release(struct device *device)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(device);
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	if (indio_dev->modes & INDIO_ALL_TRIGGERED_MODES)
+		iio_device_unregister_trigger_consumer(indio_dev);
+	iio_device_unregister_eventset(indio_dev);
+	iio_device_unregister_sysfs(indio_dev);
+
+	iio_device_detach_buffers(indio_dev);
+
+	lockdep_unregister_key(&iio_dev_opaque->mlock_key);
+
+	ida_free(&iio_ida, iio_dev_opaque->id);
+	kfree(iio_dev_opaque);
+}
+
+const struct device_type iio_device_type = {
+	.name = "iio_device",
+	.release = iio_dev_release,
+};
+
+/**
+ * iio_device_alloc() - allocate an iio_dev from a driver
+ * @parent:		Parent device.
+ * @sizeof_priv:	Space to allocate for private structure.
+ **/
+struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv)
+{
+	struct iio_dev_opaque *iio_dev_opaque;
+	struct iio_dev *indio_dev;
+	size_t alloc_size;
+
+	alloc_size = sizeof(struct iio_dev_opaque);
+	if (sizeof_priv) {
+		alloc_size = ALIGN(alloc_size, IIO_DMA_MINALIGN);
+		alloc_size += sizeof_priv;
+	}
+
+	iio_dev_opaque = kzalloc(alloc_size, GFP_KERNEL);
+	if (!iio_dev_opaque)
+		return NULL;
+
+	indio_dev = &iio_dev_opaque->indio_dev;
+	indio_dev->priv = (char *)iio_dev_opaque +
+		ALIGN(sizeof(struct iio_dev_opaque), IIO_DMA_MINALIGN);
+
+	indio_dev->dev.parent = parent;
+	indio_dev->dev.type = &iio_device_type;
+	indio_dev->dev.bus = &iio_bus_type;
+	device_initialize(&indio_dev->dev);
+	mutex_init(&indio_dev->mlock);
+	mutex_init(&iio_dev_opaque->info_exist_lock);
+	INIT_LIST_HEAD(&iio_dev_opaque->channel_attr_list);
+
+	iio_dev_opaque->id = ida_alloc(&iio_ida, GFP_KERNEL);
+	if (iio_dev_opaque->id < 0) {
+		/* cannot use a dev_err as the name isn't available */
+		pr_err("failed to get device id\n");
+		kfree(iio_dev_opaque);
+		return NULL;
+	}
+
+	if (dev_set_name(&indio_dev->dev, "iio:device%d", iio_dev_opaque->id)) {
+		ida_free(&iio_ida, iio_dev_opaque->id);
+		kfree(iio_dev_opaque);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&iio_dev_opaque->buffer_list);
+	INIT_LIST_HEAD(&iio_dev_opaque->ioctl_handlers);
+
+	lockdep_register_key(&iio_dev_opaque->mlock_key);
+	lockdep_set_class(&indio_dev->mlock, &iio_dev_opaque->mlock_key);
+
+	return indio_dev;
+}
+EXPORT_SYMBOL(iio_device_alloc);
+
+/**
+ * iio_device_free() - free an iio_dev from a driver
+ * @dev:		the iio_dev associated with the device
+ **/
+void iio_device_free(struct iio_dev *dev)
+{
+	if (dev)
+		put_device(&dev->dev);
+}
+EXPORT_SYMBOL(iio_device_free);
+
+static void devm_iio_device_release(void *iio_dev)
+{
+	iio_device_free(iio_dev);
+}
+
+/**
+ * devm_iio_device_alloc - Resource-managed iio_device_alloc()
+ * @parent:		Device to allocate iio_dev for, and parent for this IIO device
+ * @sizeof_priv:	Space to allocate for private structure.
+ *
+ * Managed iio_device_alloc. iio_dev allocated with this function is
+ * automatically freed on driver detach.
+ *
+ * RETURNS:
+ * Pointer to allocated iio_dev on success, NULL on failure.
+ */
+struct iio_dev *devm_iio_device_alloc(struct device *parent, int sizeof_priv)
+{
+	struct iio_dev *iio_dev;
+	int ret;
+
+	iio_dev = iio_device_alloc(parent, sizeof_priv);
+	if (!iio_dev)
+		return NULL;
+
+	ret = devm_add_action_or_reset(parent, devm_iio_device_release,
+				       iio_dev);
+	if (ret)
+		return NULL;
+
+	return iio_dev;
+}
+EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
+
+/**
+ * iio_chrdev_open() - chrdev file open for buffer access and ioctls
+ * @inode:	Inode structure for identifying the device in the file system
+ * @filp:	File structure for iio device used to keep and later access
+ *		private data
+ *
+ * Return: 0 on success or -EBUSY if the device is already opened
+ **/
+static int iio_chrdev_open(struct inode *inode, struct file *filp)
+{
+	struct iio_dev_opaque *iio_dev_opaque =
+		container_of(inode->i_cdev, struct iio_dev_opaque, chrdev);
+	struct iio_dev *indio_dev = &iio_dev_opaque->indio_dev;
+	struct iio_dev_buffer_pair *ib;
+
+	if (test_and_set_bit(IIO_BUSY_BIT_POS, &iio_dev_opaque->flags))
+		return -EBUSY;
+
+	iio_device_get(indio_dev);
+
+	ib = kmalloc(sizeof(*ib), GFP_KERNEL);
+	if (!ib) {
+		iio_device_put(indio_dev);
+		clear_bit(IIO_BUSY_BIT_POS, &iio_dev_opaque->flags);
+		return -ENOMEM;
+	}
+
+	ib->indio_dev = indio_dev;
+	ib->buffer = indio_dev->buffer;
+
+	filp->private_data = ib;
+
+	return 0;
+}
+
+/**
+ * iio_chrdev_release() - chrdev file close buffer access and ioctls
+ * @inode:	Inode structure pointer for the char device
+ * @filp:	File structure pointer for the char device
+ *
+ * Return: 0 for successful release
+ */
+static int iio_chrdev_release(struct inode *inode, struct file *filp)
+{
+	struct iio_dev_buffer_pair *ib = filp->private_data;
+	struct iio_dev_opaque *iio_dev_opaque =
+		container_of(inode->i_cdev, struct iio_dev_opaque, chrdev);
+	struct iio_dev *indio_dev = &iio_dev_opaque->indio_dev;
+
+	kfree(ib);
+	clear_bit(IIO_BUSY_BIT_POS, &iio_dev_opaque->flags);
+	iio_device_put(indio_dev);
+
+	return 0;
+}
+
+void iio_device_ioctl_handler_register(struct iio_dev *indio_dev,
+				       struct iio_ioctl_handler *h)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	list_add_tail(&h->entry, &iio_dev_opaque->ioctl_handlers);
+}
+
+void iio_device_ioctl_handler_unregister(struct iio_ioctl_handler *h)
+{
+	list_del(&h->entry);
+}
+
+static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct iio_dev_buffer_pair *ib = filp->private_data;
+	struct iio_dev *indio_dev = ib->indio_dev;
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	struct iio_ioctl_handler *h;
+	int ret = -ENODEV;
+
+	mutex_lock(&iio_dev_opaque->info_exist_lock);
+
+	/**
+	 * The NULL check here is required to prevent crashing when a device
+	 * is being removed while userspace would still have open file handles
+	 * to try to access this device.
+	 */
+	if (!indio_dev->info)
+		goto out_unlock;
+
+	list_for_each_entry(h, &iio_dev_opaque->ioctl_handlers, entry) {
+		ret = h->ioctl(indio_dev, filp, cmd, arg);
+		if (ret != IIO_IOCTL_UNHANDLED)
+			break;
+	}
+
+	if (ret == IIO_IOCTL_UNHANDLED)
+		ret = -ENODEV;
+
+out_unlock:
+	mutex_unlock(&iio_dev_opaque->info_exist_lock);
+
+	return ret;
+}
+
+static const struct file_operations iio_buffer_fileops = {
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.read = iio_buffer_read_outer_addr,
+	.write = iio_buffer_write_outer_addr,
+	.poll = iio_buffer_poll_addr,
+	.unlocked_ioctl = iio_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+	.open = iio_chrdev_open,
+	.release = iio_chrdev_release,
+};
+
+static const struct file_operations iio_event_fileops = {
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = iio_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+	.open = iio_chrdev_open,
+	.release = iio_chrdev_release,
+};
+
+static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
+{
+	int i, j;
+	const struct iio_chan_spec *channels = indio_dev->channels;
+
+	if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
+		return 0;
+
+	for (i = 0; i < indio_dev->num_channels - 1; i++) {
+		if (channels[i].scan_index < 0)
+			continue;
+		for (j = i + 1; j < indio_dev->num_channels; j++)
+			if (channels[i].scan_index == channels[j].scan_index) {
+				dev_err(&indio_dev->dev,
+					"Duplicate scan index %d\n",
+					channels[i].scan_index);
+				return -EINVAL;
+			}
+	}
+
+	return 0;
+}
+
+static int iio_check_extended_name(const struct iio_dev *indio_dev)
+{
+	unsigned int i;
+
+	if (!indio_dev->info->read_label)
+		return 0;
+
+	for (i = 0; i < indio_dev->num_channels; i++) {
+		if (indio_dev->channels[i].extend_name) {
+			dev_err(&indio_dev->dev,
+				"Cannot use labels and extend_name at the same time\n");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static const struct iio_buffer_setup_ops noop_ring_setup_ops;
+
+int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	struct fwnode_handle *fwnode = NULL;
+	int ret;
+
+	if (!indio_dev->info)
+		return -EINVAL;
+
+	iio_dev_opaque->driver_module = this_mod;
+
+	/* If the calling driver did not initialize firmware node, do it here */
+	if (dev_fwnode(&indio_dev->dev))
+		fwnode = dev_fwnode(&indio_dev->dev);
+	/* The default dummy IIO device has no parent */
+	else if (indio_dev->dev.parent)
+		fwnode = dev_fwnode(indio_dev->dev.parent);
+	device_set_node(&indio_dev->dev, fwnode);
+
+	fwnode_property_read_string(fwnode, "label", &indio_dev->label);
+
+	ret = iio_check_unique_scan_index(indio_dev);
+	if (ret < 0)
+		return ret;
+
+	ret = iio_check_extended_name(indio_dev);
+	if (ret < 0)
+		return ret;
+
+	iio_device_register_debugfs(indio_dev);
+
+	ret = iio_buffers_alloc_sysfs_and_mask(indio_dev);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"Failed to create buffer sysfs interfaces\n");
+		goto error_unreg_debugfs;
+	}
+
+	ret = iio_device_register_sysfs(indio_dev);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"Failed to register sysfs interfaces\n");
+		goto error_buffer_free_sysfs;
+	}
+	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_ALL_TRIGGERED_MODES)
+		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;
+
+	if (iio_dev_opaque->attached_buffers_cnt)
+		cdev_init(&iio_dev_opaque->chrdev, &iio_buffer_fileops);
+	else if (iio_dev_opaque->event_interface)
+		cdev_init(&iio_dev_opaque->chrdev, &iio_event_fileops);
+
+	if (iio_dev_opaque->attached_buffers_cnt || iio_dev_opaque->event_interface) {
+		indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), iio_dev_opaque->id);
+		iio_dev_opaque->chrdev.owner = this_mod;
+	}
+
+	/* assign device groups now; they should be all registered now */
+	indio_dev->dev.groups = iio_dev_opaque->groups;
+
+	ret = cdev_device_add(&iio_dev_opaque->chrdev, &indio_dev->dev);
+	if (ret < 0)
+		goto error_unreg_eventset;
+
+	return 0;
+
+error_unreg_eventset:
+	iio_device_unregister_eventset(indio_dev);
+error_free_sysfs:
+	iio_device_unregister_sysfs(indio_dev);
+error_buffer_free_sysfs:
+	iio_buffers_free_sysfs_and_mask(indio_dev);
+error_unreg_debugfs:
+	iio_device_unregister_debugfs(indio_dev);
+	return ret;
+}
+EXPORT_SYMBOL(__iio_device_register);
+
+/**
+ * iio_device_unregister() - unregister a device from the IIO subsystem
+ * @indio_dev:		Device structure representing the device.
+ **/
+void iio_device_unregister(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	cdev_device_del(&iio_dev_opaque->chrdev, &indio_dev->dev);
+
+	mutex_lock(&iio_dev_opaque->info_exist_lock);
+
+	iio_device_unregister_debugfs(indio_dev);
+
+	iio_disable_all_buffers(indio_dev);
+
+	indio_dev->info = NULL;
+
+	iio_device_wakeup_eventset(indio_dev);
+	iio_buffer_wakeup_poll(indio_dev);
+
+	mutex_unlock(&iio_dev_opaque->info_exist_lock);
+
+	iio_buffers_free_sysfs_and_mask(indio_dev);
+}
+EXPORT_SYMBOL(iio_device_unregister);
+
+static void devm_iio_device_unreg(void *indio_dev)
+{
+	iio_device_unregister(indio_dev);
+}
+
+int __devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev,
+			       struct module *this_mod)
+{
+	int ret;
+
+	ret = __iio_device_register(indio_dev, this_mod);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, devm_iio_device_unreg, indio_dev);
+}
+EXPORT_SYMBOL_GPL(__devm_iio_device_register);
+
+/**
+ * iio_device_claim_direct_mode - Keep device in direct mode
+ * @indio_dev:	the iio_dev associated with the device
+ *
+ * If the device is in direct mode it is guaranteed to stay
+ * that way until iio_device_release_direct_mode() is called.
+ *
+ * Use with iio_device_release_direct_mode()
+ *
+ * Returns: 0 on success, -EBUSY on failure
+ */
+int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
+{
+	mutex_lock(&indio_dev->mlock);
+
+	if (iio_buffer_enabled(indio_dev)) {
+		mutex_unlock(&indio_dev->mlock);
+		return -EBUSY;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iio_device_claim_direct_mode);
+
+/**
+ * iio_device_release_direct_mode - releases claim on direct mode
+ * @indio_dev:	the iio_dev associated with the device
+ *
+ * Release the claim. Device is no longer guaranteed to stay
+ * in direct mode.
+ *
+ * Use with iio_device_claim_direct_mode()
+ */
+void iio_device_release_direct_mode(struct iio_dev *indio_dev)
+{
+	mutex_unlock(&indio_dev->mlock);
+}
+EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
+
+/**
+ * iio_device_claim_buffer_mode - Keep device in buffer mode
+ * @indio_dev:	the iio_dev associated with the device
+ *
+ * If the device is in buffer mode it is guaranteed to stay
+ * that way until iio_device_release_buffer_mode() is called.
+ *
+ * Use with iio_device_release_buffer_mode().
+ *
+ * Returns: 0 on success, -EBUSY on failure.
+ */
+int iio_device_claim_buffer_mode(struct iio_dev *indio_dev)
+{
+	mutex_lock(&indio_dev->mlock);
+
+	if (iio_buffer_enabled(indio_dev))
+		return 0;
+
+	mutex_unlock(&indio_dev->mlock);
+	return -EBUSY;
+}
+EXPORT_SYMBOL_GPL(iio_device_claim_buffer_mode);
+
+/**
+ * iio_device_release_buffer_mode - releases claim on buffer mode
+ * @indio_dev:	the iio_dev associated with the device
+ *
+ * Release the claim. Device is no longer guaranteed to stay
+ * in buffer mode.
+ *
+ * Use with iio_device_claim_buffer_mode().
+ */
+void iio_device_release_buffer_mode(struct iio_dev *indio_dev)
+{
+	mutex_unlock(&indio_dev->mlock);
+}
+EXPORT_SYMBOL_GPL(iio_device_release_buffer_mode);
+
+/**
+ * iio_device_get_current_mode() - helper function providing read-only access to
+ *				   the opaque @currentmode variable
+ * @indio_dev:			   IIO device structure for device
+ */
+int iio_device_get_current_mode(struct iio_dev *indio_dev)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	return iio_dev_opaque->currentmode;
+}
+EXPORT_SYMBOL_GPL(iio_device_get_current_mode);
+
+subsys_initcall(iio_init);
+module_exit(iio_exit);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("Industrial I/O core");
+MODULE_LICENSE("GPL");