Initial import

1 files changed, 1338 insertions, 0 deletions

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
new file mode 100644
index 000000000..4df97f650
--- /dev/null
+++ b/drivers/iio/industrialio-core.c
@@ -0,0 +1,1338 @@
+/* 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.
+ */
+
+#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/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>
+#include <linux/iio/buffer.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",
+};
+
+static const char * const iio_modifier_names[] = {
+	[IIO_MOD_X] = "x",
+	[IIO_MOD_Y] = "y",
+	[IIO_MOD_Z] = "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_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)",
+};
+
+/* 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",
+	[IIO_CHAN_INFO_FREQUENCY] = "frequency",
+	[IIO_CHAN_INFO_PHASE] = "phase",
+	[IIO_CHAN_INFO_HARDWAREGAIN] = "hardwaregain",
+	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
+	[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_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 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) {
+		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;
+	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 = simple_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 (!iio_debugfs_dentry)
+		return 0;
+
+	indio_dev->debugfs_dentry =
+		debugfs_create_dir(dev_name(&indio_dev->dev),
+				   iio_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_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)
+		len += scnprintf(buf + len, PAGE_SIZE - 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)
+		return -EINVAL;
+
+	return snprintf(buf, PAGE_SIZE, "%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;
+	unsigned int i;
+	int ret;
+
+	if (!e->set)
+		return -EINVAL;
+
+	for (i = 0; i < e->num_items; i++) {
+		if (sysfs_streq(buf, e->items[i]))
+			break;
+	}
+
+	if (i == e->num_items)
+		return -EINVAL;
+
+	ret = e->set(indio_dev, chan, i);
+	return ret ? ret : len;
+}
+EXPORT_SYMBOL_GPL(iio_enum_write);
+
+/**
+ * iio_format_value() - Formats a IIO value into its string representation
+ * @buf: The buffer to which the formated value gets written
+ * @type: One of the IIO_VAL_... constants. This decides how the val and val2
+ *        parameters are formatted.
+ * @vals: pointer to the values, exact meaning depends on the type parameter.
+ */
+ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
+{
+	unsigned long long tmp;
+	bool scale_db = false;
+
+	switch (type) {
+	case IIO_VAL_INT:
+		return sprintf(buf, "%d\n", vals[0]);
+	case IIO_VAL_INT_PLUS_MICRO_DB:
+		scale_db = true;
+	case IIO_VAL_INT_PLUS_MICRO:
+		if (vals[1] < 0)
+			return sprintf(buf, "-%ld.%06u%s\n", abs(vals[0]),
+					-vals[1],
+				scale_db ? " dB" : "");
+		else
+			return sprintf(buf, "%d.%06u%s\n", vals[0], vals[1],
+				scale_db ? " dB" : "");
+	case IIO_VAL_INT_PLUS_NANO:
+		if (vals[1] < 0)
+			return sprintf(buf, "-%ld.%09u\n", abs(vals[0]),
+					-vals[1]);
+		else
+			return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
+	case IIO_VAL_FRACTIONAL:
+		tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
+		vals[1] = do_div(tmp, 1000000000LL);
+		vals[0] = tmp;
+		return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
+	case IIO_VAL_FRACTIONAL_LOG2:
+		tmp = (s64)vals[0] * 1000000000LL >> vals[1];
+		vals[1] = do_div(tmp, 1000000000LL);
+		vals[0] = tmp;
+		return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
+	case IIO_VAL_INT_MULTIPLE:
+	{
+		int i;
+		int len = 0;
+
+		for (i = 0; i < size; ++i)
+			len += snprintf(&buf[len], PAGE_SIZE - len, "%d ",
+								vals[i]);
+		len += snprintf(&buf[len], PAGE_SIZE - len, "\n");
+		return len;
+	}
+	default:
+		return 0;
+	}
+}
+
+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);
+}
+
+/**
+ * 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)
+{
+	int i = 0, f = 0;
+	bool integer_part = true, negative = false;
+
+	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;
+			else
+				return -EINVAL;
+		} 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;
+}
+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;
+
+	/* 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;
+		}
+
+	ret = iio_str_to_fixpoint(buf, fract_mult, &integer, &fract);
+	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_ON("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 |= S_IRUGO;
+		dev_attr->show = readfunc;
+	}
+
+	if (writefunc) {
+		dev_attr->attr.mode |= S_IWUSR;
+		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 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;
+	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_info_mask_type(struct iio_dev *indio_dev,
+					 struct iio_chan_spec const *chan,
+					 enum iio_shared_by shared_by,
+					 const long *infomask)
+{
+	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,
+					     &indio_dev->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_channel_sysfs(struct iio_dev *indio_dev,
+					struct iio_chan_spec const *chan)
+{
+	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(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(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(indio_dev, chan,
+					    IIO_SHARED_BY_ALL,
+					    &chan->info_mask_shared_by_all);
+	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,
+					&indio_dev->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(p->dev_attr.attr.name);
+		list_del(&p->l);
+		kfree(p);
+	}
+}
+
+static ssize_t iio_show_dev_name(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	return snprintf(buf, PAGE_SIZE, "%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;
+	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 its name is NULL.
+	 */
+	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:
+	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
+
+	return ret;
+}
+
+static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
+{
+
+	iio_free_chan_devattr_list(&indio_dev->channel_attr_list);
+	kfree(indio_dev->chan_attr_group.attrs);
+	indio_dev->chan_attr_group.attrs = NULL;
+}
+
+static void iio_dev_release(struct device *device)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(device);
+	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_buffer_put(indio_dev->buffer);
+
+	ida_simple_remove(&iio_ida, indio_dev->id);
+	kfree(indio_dev);
+}
+
+struct device_type iio_device_type = {
+	.name = "iio_device",
+	.release = iio_dev_release,
+};
+
+/**
+ * iio_device_alloc() - allocate an iio_dev from a driver
+ * @sizeof_priv:	Space to allocate for private structure.
+ **/
+struct iio_dev *iio_device_alloc(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_device_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);
+		INIT_LIST_HEAD(&dev->channel_attr_list);
+
+		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 */
+			pr_err("failed to get device id\n");
+			kfree(dev);
+			return NULL;
+		}
+		dev_set_name(&dev->dev, "iio:device%d", dev->id);
+		INIT_LIST_HEAD(&dev->buffer_list);
+	}
+
+	return 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(struct device *dev, void *res)
+{
+	iio_device_free(*(struct iio_dev **)res);
+}
+
+static int devm_iio_device_match(struct device *dev, void *res, void *data)
+{
+	struct iio_dev **r = res;
+	if (!r || !*r) {
+		WARN_ON(!r || !*r);
+		return 0;
+	}
+	return *r == data;
+}
+
+/**
+ * devm_iio_device_alloc - Resource-managed iio_device_alloc()
+ * @dev:		Device to allocate iio_dev for
+ * @sizeof_priv:	Space to allocate for private structure.
+ *
+ * Managed iio_device_alloc. iio_dev allocated with this function is
+ * automatically freed on driver detach.
+ *
+ * If an iio_dev allocated with this function needs to be freed separately,
+ * devm_iio_device_free() must be used.
+ *
+ * RETURNS:
+ * Pointer to allocated iio_dev on success, NULL on failure.
+ */
+struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
+{
+	struct iio_dev **ptr, *iio_dev;
+
+	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
+			   GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	iio_dev = iio_device_alloc(sizeof_priv);
+	if (iio_dev) {
+		*ptr = iio_dev;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return iio_dev;
+}
+EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
+
+/**
+ * devm_iio_device_free - Resource-managed iio_device_free()
+ * @dev:		Device this iio_dev belongs to
+ * @iio_dev:		the iio_dev associated with the device
+ *
+ * Free iio_dev allocated with devm_iio_device_alloc().
+ */
+void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev)
+{
+	int rc;
+
+	rc = devres_release(dev, devm_iio_device_release,
+			    devm_iio_device_match, iio_dev);
+	WARN_ON(rc);
+}
+EXPORT_SYMBOL_GPL(devm_iio_device_free);
+
+/**
+ * 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;
+
+	iio_device_get(indio_dev);
+
+	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);
+	iio_device_put(indio_dev);
+
+	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 (!indio_dev->info)
+		return -ENODEV;
+
+	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 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 const struct iio_buffer_setup_ops noop_ring_setup_ops;
+
+/**
+ * iio_device_register() - register a device with the IIO subsystem
+ * @indio_dev:		Device structure filled by the device driver
+ **/
+int iio_device_register(struct iio_dev *indio_dev)
+{
+	int ret;
+
+	/* If the calling driver did not initialize of_node, do it here */
+	if (!indio_dev->dev.of_node && indio_dev->dev.parent)
+		indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
+
+	ret = iio_check_unique_scan_index(indio_dev);
+	if (ret < 0)
+		return 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");
+		return ret;
+	}
+
+	ret = iio_buffer_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_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;
+
+	cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
+	indio_dev->chrdev.owner = indio_dev->info->driver_module;
+	indio_dev->chrdev.kobj.parent = &indio_dev->dev.kobj;
+	ret = cdev_add(&indio_dev->chrdev, indio_dev->dev.devt, 1);
+	if (ret < 0)
+		goto error_unreg_eventset;
+
+	ret = device_add(&indio_dev->dev);
+	if (ret < 0)
+		goto error_cdev_del;
+
+	return 0;
+error_cdev_del:
+	cdev_del(&indio_dev->chrdev);
+error_unreg_eventset:
+	iio_device_unregister_eventset(indio_dev);
+error_free_sysfs:
+	iio_device_unregister_sysfs(indio_dev);
+error_buffer_free_sysfs:
+	iio_buffer_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)
+{
+	mutex_lock(&indio_dev->info_exist_lock);
+
+	device_del(&indio_dev->dev);
+
+	if (indio_dev->chrdev.dev)
+		cdev_del(&indio_dev->chrdev);
+	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(&indio_dev->info_exist_lock);
+
+	iio_buffer_free_sysfs_and_mask(indio_dev);
+}
+EXPORT_SYMBOL(iio_device_unregister);
+
+static void devm_iio_device_unreg(struct device *dev, void *res)
+{
+	iio_device_unregister(*(struct iio_dev **)res);
+}
+
+/**
+ * devm_iio_device_register - Resource-managed iio_device_register()
+ * @dev:	Device to allocate iio_dev for
+ * @indio_dev:	Device structure filled by the device driver
+ *
+ * Managed iio_device_register.  The IIO device registered with this
+ * function is automatically unregistered on driver detach. This function
+ * calls iio_device_register() internally. Refer to that function for more
+ * information.
+ *
+ * If an iio_dev registered with this function needs to be unregistered
+ * separately, devm_iio_device_unregister() must be used.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int devm_iio_device_register(struct device *dev, struct iio_dev *indio_dev)
+{
+	struct iio_dev **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_iio_device_unreg, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	*ptr = indio_dev;
+	ret = iio_device_register(indio_dev);
+	if (!ret)
+		devres_add(dev, ptr);
+	else
+		devres_free(ptr);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_iio_device_register);
+
+/**
+ * devm_iio_device_unregister - Resource-managed iio_device_unregister()
+ * @dev:	Device this iio_dev belongs to
+ * @indio_dev:	the iio_dev associated with the device
+ *
+ * Unregister iio_dev registered with devm_iio_device_register().
+ */
+void devm_iio_device_unregister(struct device *dev, struct iio_dev *indio_dev)
+{
+	int rc;
+
+	rc = devres_release(dev, devm_iio_device_unreg,
+			    devm_iio_device_match, indio_dev);
+	WARN_ON(rc);
+}
+EXPORT_SYMBOL_GPL(devm_iio_device_unregister);
+
+subsys_initcall(iio_init);
+module_exit(iio_exit);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("Industrial I/O core");
+MODULE_LICENSE("GPL");