1 files changed, 783 insertions, 0 deletions

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
new file mode 100644
index 0000000000..18f83158f6
--- /dev/null
+++ b/drivers/iio/industrialio-trigger.c
@@ -0,0 +1,783 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* The industrial I/O core, trigger handling functions
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ */
+
+#include <linux/kernel.h>
+#include <linux/idr.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/iio-opaque.h>
+#include <linux/iio/trigger.h>
+#include "iio_core.h"
+#include "iio_core_trigger.h"
+#include <linux/iio/trigger_consumer.h>
+
+/* RFC - Question of approach
+ * Make the common case (single sensor single trigger)
+ * simple by starting trigger capture from when first sensors
+ * is added.
+ *
+ * Complex simultaneous start requires use of 'hold' functionality
+ * of the trigger. (not implemented)
+ *
+ * Any other suggestions?
+ */
+
+static DEFINE_IDA(iio_trigger_ida);
+
+/* Single list of all available triggers */
+static LIST_HEAD(iio_trigger_list);
+static DEFINE_MUTEX(iio_trigger_list_lock);
+
+/**
+ * name_show() - retrieve useful identifying name
+ * @dev:	device associated with the iio_trigger
+ * @attr:	pointer to the device_attribute structure that is
+ *		being processed
+ * @buf:	buffer to print the name into
+ *
+ * Return: a negative number on failure or the number of written
+ *	   characters on success.
+ */
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+
+	return sysfs_emit(buf, "%s\n", trig->name);
+}
+
+static DEVICE_ATTR_RO(name);
+
+static struct attribute *iio_trig_dev_attrs[] = {
+	&dev_attr_name.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(iio_trig_dev);
+
+static struct iio_trigger *__iio_trigger_find_by_name(const char *name);
+
+int iio_trigger_register(struct iio_trigger *trig_info)
+{
+	int ret;
+
+	trig_info->id = ida_alloc(&iio_trigger_ida, GFP_KERNEL);
+	if (trig_info->id < 0)
+		return trig_info->id;
+
+	/* Set the name used for the sysfs directory etc */
+	dev_set_name(&trig_info->dev, "trigger%d", trig_info->id);
+
+	ret = device_add(&trig_info->dev);
+	if (ret)
+		goto error_unregister_id;
+
+	/* Add to list of available triggers held by the IIO core */
+	mutex_lock(&iio_trigger_list_lock);
+	if (__iio_trigger_find_by_name(trig_info->name)) {
+		pr_err("Duplicate trigger name '%s'\n", trig_info->name);
+		ret = -EEXIST;
+		goto error_device_del;
+	}
+	list_add_tail(&trig_info->list, &iio_trigger_list);
+	mutex_unlock(&iio_trigger_list_lock);
+
+	return 0;
+
+error_device_del:
+	mutex_unlock(&iio_trigger_list_lock);
+	device_del(&trig_info->dev);
+error_unregister_id:
+	ida_free(&iio_trigger_ida, trig_info->id);
+	return ret;
+}
+EXPORT_SYMBOL(iio_trigger_register);
+
+void iio_trigger_unregister(struct iio_trigger *trig_info)
+{
+	mutex_lock(&iio_trigger_list_lock);
+	list_del(&trig_info->list);
+	mutex_unlock(&iio_trigger_list_lock);
+
+	ida_free(&iio_trigger_ida, trig_info->id);
+	/* Possible issue in here */
+	device_del(&trig_info->dev);
+}
+EXPORT_SYMBOL(iio_trigger_unregister);
+
+int iio_trigger_set_immutable(struct iio_dev *indio_dev, struct iio_trigger *trig)
+{
+	struct iio_dev_opaque *iio_dev_opaque;
+
+	if (!indio_dev || !trig)
+		return -EINVAL;
+
+	iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	mutex_lock(&iio_dev_opaque->mlock);
+	WARN_ON(iio_dev_opaque->trig_readonly);
+
+	indio_dev->trig = iio_trigger_get(trig);
+	iio_dev_opaque->trig_readonly = true;
+	mutex_unlock(&iio_dev_opaque->mlock);
+
+	return 0;
+}
+EXPORT_SYMBOL(iio_trigger_set_immutable);
+
+/* Search for trigger by name, assuming iio_trigger_list_lock held */
+static struct iio_trigger *__iio_trigger_find_by_name(const char *name)
+{
+	struct iio_trigger *iter;
+
+	list_for_each_entry(iter, &iio_trigger_list, list)
+		if (!strcmp(iter->name, name))
+			return iter;
+
+	return NULL;
+}
+
+static struct iio_trigger *iio_trigger_acquire_by_name(const char *name)
+{
+	struct iio_trigger *trig = NULL, *iter;
+
+	mutex_lock(&iio_trigger_list_lock);
+	list_for_each_entry(iter, &iio_trigger_list, list)
+		if (sysfs_streq(iter->name, name)) {
+			trig = iter;
+			iio_trigger_get(trig);
+			break;
+		}
+	mutex_unlock(&iio_trigger_list_lock);
+
+	return trig;
+}
+
+static void iio_reenable_work_fn(struct work_struct *work)
+{
+	struct iio_trigger *trig = container_of(work, struct iio_trigger,
+						reenable_work);
+
+	/*
+	 * This 'might' occur after the trigger state is set to disabled -
+	 * in that case the driver should skip reenabling.
+	 */
+	trig->ops->reenable(trig);
+}
+
+/*
+ * In general, reenable callbacks may need to sleep and this path is
+ * not performance sensitive, so just queue up a work item
+ * to reneable the trigger for us.
+ *
+ * Races that can cause this.
+ * 1) A handler occurs entirely in interrupt context so the counter
+ *    the final decrement is still in this interrupt.
+ * 2) The trigger has been removed, but one last interrupt gets through.
+ *
+ * For (1) we must call reenable, but not in atomic context.
+ * For (2) it should be safe to call reenanble, if drivers never blindly
+ * reenable after state is off.
+ */
+static void iio_trigger_notify_done_atomic(struct iio_trigger *trig)
+{
+	if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
+	    trig->ops->reenable)
+		schedule_work(&trig->reenable_work);
+}
+
+/**
+ * iio_trigger_poll() - Call the IRQ trigger handler of the consumers
+ * @trig: trigger which occurred
+ *
+ * This function should only be called from a hard IRQ context.
+ */
+void iio_trigger_poll(struct iio_trigger *trig)
+{
+	int i;
+
+	if (!atomic_read(&trig->use_count)) {
+		atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+			if (trig->subirqs[i].enabled)
+				generic_handle_irq(trig->subirq_base + i);
+			else
+				iio_trigger_notify_done_atomic(trig);
+		}
+	}
+}
+EXPORT_SYMBOL(iio_trigger_poll);
+
+irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
+{
+	iio_trigger_poll(private);
+	return IRQ_HANDLED;
+}
+EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
+
+/**
+ * iio_trigger_poll_nested() - Call the threaded trigger handler of the
+ * consumers
+ * @trig: trigger which occurred
+ *
+ * This function should only be called from a kernel thread context.
+ */
+void iio_trigger_poll_nested(struct iio_trigger *trig)
+{
+	int i;
+
+	if (!atomic_read(&trig->use_count)) {
+		atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+			if (trig->subirqs[i].enabled)
+				handle_nested_irq(trig->subirq_base + i);
+			else
+				iio_trigger_notify_done(trig);
+		}
+	}
+}
+EXPORT_SYMBOL(iio_trigger_poll_nested);
+
+void iio_trigger_notify_done(struct iio_trigger *trig)
+{
+	if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
+	    trig->ops->reenable)
+		trig->ops->reenable(trig);
+}
+EXPORT_SYMBOL(iio_trigger_notify_done);
+
+/* Trigger Consumer related functions */
+static int iio_trigger_get_irq(struct iio_trigger *trig)
+{
+	int ret;
+
+	mutex_lock(&trig->pool_lock);
+	ret = bitmap_find_free_region(trig->pool,
+				      CONFIG_IIO_CONSUMERS_PER_TRIGGER,
+				      ilog2(1));
+	mutex_unlock(&trig->pool_lock);
+	if (ret >= 0)
+		ret += trig->subirq_base;
+
+	return ret;
+}
+
+static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
+{
+	mutex_lock(&trig->pool_lock);
+	clear_bit(irq - trig->subirq_base, trig->pool);
+	mutex_unlock(&trig->pool_lock);
+}
+
+/* Complexity in here.  With certain triggers (datardy) an acknowledgement
+ * may be needed if the pollfuncs do not include the data read for the
+ * triggering device.
+ * This is not currently handled.  Alternative of not enabling trigger unless
+ * the relevant function is in there may be the best option.
+ */
+/* Worth protecting against double additions? */
+int iio_trigger_attach_poll_func(struct iio_trigger *trig,
+				 struct iio_poll_func *pf)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
+	bool notinuse =
+		bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+	int ret = 0;
+
+	/* Prevent the module from being removed whilst attached to a trigger */
+	__module_get(iio_dev_opaque->driver_module);
+
+	/* Get irq number */
+	pf->irq = iio_trigger_get_irq(trig);
+	if (pf->irq < 0) {
+		pr_err("Could not find an available irq for trigger %s, CONFIG_IIO_CONSUMERS_PER_TRIGGER=%d limit might be exceeded\n",
+			trig->name, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+		goto out_put_module;
+	}
+
+	/* Request irq */
+	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
+				   pf->type, pf->name,
+				   pf);
+	if (ret < 0)
+		goto out_put_irq;
+
+	/* Enable trigger in driver */
+	if (trig->ops && trig->ops->set_trigger_state && notinuse) {
+		ret = trig->ops->set_trigger_state(trig, true);
+		if (ret)
+			goto out_free_irq;
+	}
+
+	/*
+	 * Check if we just registered to our own trigger: we determine that
+	 * this is the case if the IIO device and the trigger device share the
+	 * same parent device.
+	 */
+	if (iio_validate_own_trigger(pf->indio_dev, trig))
+		trig->attached_own_device = true;
+
+	return ret;
+
+out_free_irq:
+	free_irq(pf->irq, pf);
+out_put_irq:
+	iio_trigger_put_irq(trig, pf->irq);
+out_put_module:
+	module_put(iio_dev_opaque->driver_module);
+	return ret;
+}
+
+int iio_trigger_detach_poll_func(struct iio_trigger *trig,
+				 struct iio_poll_func *pf)
+{
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
+	bool no_other_users =
+		bitmap_weight(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER) == 1;
+	int ret = 0;
+
+	if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
+		ret = trig->ops->set_trigger_state(trig, false);
+		if (ret)
+			return ret;
+	}
+	if (pf->indio_dev->dev.parent == trig->dev.parent)
+		trig->attached_own_device = false;
+	iio_trigger_put_irq(trig, pf->irq);
+	free_irq(pf->irq, pf);
+	module_put(iio_dev_opaque->driver_module);
+
+	return ret;
+}
+
+irqreturn_t iio_pollfunc_store_time(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+
+	pf->timestamp = iio_get_time_ns(pf->indio_dev);
+	return IRQ_WAKE_THREAD;
+}
+EXPORT_SYMBOL(iio_pollfunc_store_time);
+
+struct iio_poll_func
+*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
+		    irqreturn_t (*thread)(int irq, void *p),
+		    int type,
+		    struct iio_dev *indio_dev,
+		    const char *fmt,
+		    ...)
+{
+	va_list vargs;
+	struct iio_poll_func *pf;
+
+	pf = kmalloc(sizeof(*pf), GFP_KERNEL);
+	if (!pf)
+		return NULL;
+	va_start(vargs, fmt);
+	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
+	va_end(vargs);
+	if (pf->name == NULL) {
+		kfree(pf);
+		return NULL;
+	}
+	pf->h = h;
+	pf->thread = thread;
+	pf->type = type;
+	pf->indio_dev = indio_dev;
+
+	return pf;
+}
+EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
+
+void iio_dealloc_pollfunc(struct iio_poll_func *pf)
+{
+	kfree(pf->name);
+	kfree(pf);
+}
+EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
+
+/**
+ * current_trigger_show() - trigger consumer sysfs query current trigger
+ * @dev:	device associated with an industrial I/O device
+ * @attr:	pointer to the device_attribute structure that
+ *		is being processed
+ * @buf:	buffer where the current trigger name will be printed into
+ *
+ * For trigger consumers the current_trigger interface allows the trigger
+ * used by the device to be queried.
+ *
+ * Return: a negative number on failure, the number of characters written
+ *	   on success or 0 if no trigger is available
+ */
+static ssize_t current_trigger_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+
+	if (indio_dev->trig)
+		return sysfs_emit(buf, "%s\n", indio_dev->trig->name);
+	return 0;
+}
+
+/**
+ * current_trigger_store() - trigger consumer sysfs set current trigger
+ * @dev:	device associated with an industrial I/O device
+ * @attr:	device attribute that is being processed
+ * @buf:	string buffer that holds the name of the trigger
+ * @len:	length of the trigger name held by buf
+ *
+ * For trigger consumers the current_trigger interface allows the trigger
+ * used for this device to be specified at run time based on the trigger's
+ * name.
+ *
+ * Return: negative error code on failure or length of the buffer
+ *	   on success
+ */
+static ssize_t current_trigger_store(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_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	struct iio_trigger *oldtrig = indio_dev->trig;
+	struct iio_trigger *trig;
+	int ret;
+
+	mutex_lock(&iio_dev_opaque->mlock);
+	if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
+		mutex_unlock(&iio_dev_opaque->mlock);
+		return -EBUSY;
+	}
+	if (iio_dev_opaque->trig_readonly) {
+		mutex_unlock(&iio_dev_opaque->mlock);
+		return -EPERM;
+	}
+	mutex_unlock(&iio_dev_opaque->mlock);
+
+	trig = iio_trigger_acquire_by_name(buf);
+	if (oldtrig == trig) {
+		ret = len;
+		goto out_trigger_put;
+	}
+
+	if (trig && indio_dev->info->validate_trigger) {
+		ret = indio_dev->info->validate_trigger(indio_dev, trig);
+		if (ret)
+			goto out_trigger_put;
+	}
+
+	if (trig && trig->ops && trig->ops->validate_device) {
+		ret = trig->ops->validate_device(trig, indio_dev);
+		if (ret)
+			goto out_trigger_put;
+	}
+
+	indio_dev->trig = trig;
+
+	if (oldtrig) {
+		if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
+			iio_trigger_detach_poll_func(oldtrig,
+						     indio_dev->pollfunc_event);
+		iio_trigger_put(oldtrig);
+	}
+	if (indio_dev->trig) {
+		if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
+			iio_trigger_attach_poll_func(indio_dev->trig,
+						     indio_dev->pollfunc_event);
+	}
+
+	return len;
+
+out_trigger_put:
+	if (trig)
+		iio_trigger_put(trig);
+	return ret;
+}
+
+static DEVICE_ATTR_RW(current_trigger);
+
+static struct attribute *iio_trigger_consumer_attrs[] = {
+	&dev_attr_current_trigger.attr,
+	NULL,
+};
+
+static const struct attribute_group iio_trigger_consumer_attr_group = {
+	.name = "trigger",
+	.attrs = iio_trigger_consumer_attrs,
+};
+
+static void iio_trig_release(struct device *device)
+{
+	struct iio_trigger *trig = to_iio_trigger(device);
+	int i;
+
+	if (trig->subirq_base) {
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+			irq_modify_status(trig->subirq_base + i,
+					  IRQ_NOAUTOEN,
+					  IRQ_NOREQUEST | IRQ_NOPROBE);
+			irq_set_chip(trig->subirq_base + i,
+				     NULL);
+			irq_set_handler(trig->subirq_base + i,
+					NULL);
+		}
+
+		irq_free_descs(trig->subirq_base,
+			       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+	}
+	kfree(trig->name);
+	kfree(trig);
+}
+
+static const struct device_type iio_trig_type = {
+	.release = iio_trig_release,
+	.groups = iio_trig_dev_groups,
+};
+
+static void iio_trig_subirqmask(struct irq_data *d)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
+
+	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
+}
+
+static void iio_trig_subirqunmask(struct irq_data *d)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
+
+	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
+}
+
+static __printf(3, 0)
+struct iio_trigger *viio_trigger_alloc(struct device *parent,
+				       struct module *this_mod,
+				       const char *fmt,
+				       va_list vargs)
+{
+	struct iio_trigger *trig;
+	int i;
+
+	trig = kzalloc(sizeof(*trig), GFP_KERNEL);
+	if (!trig)
+		return NULL;
+
+	trig->dev.parent = parent;
+	trig->dev.type = &iio_trig_type;
+	trig->dev.bus = &iio_bus_type;
+	device_initialize(&trig->dev);
+	INIT_WORK(&trig->reenable_work, iio_reenable_work_fn);
+
+	mutex_init(&trig->pool_lock);
+	trig->subirq_base = irq_alloc_descs(-1, 0,
+					    CONFIG_IIO_CONSUMERS_PER_TRIGGER,
+					    0);
+	if (trig->subirq_base < 0)
+		goto free_trig;
+
+	trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
+	if (trig->name == NULL)
+		goto free_descs;
+
+	INIT_LIST_HEAD(&trig->list);
+
+	trig->owner = this_mod;
+
+	trig->subirq_chip.name = trig->name;
+	trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
+	trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
+	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+		irq_set_chip(trig->subirq_base + i, &trig->subirq_chip);
+		irq_set_handler(trig->subirq_base + i, &handle_simple_irq);
+		irq_modify_status(trig->subirq_base + i,
+				  IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
+	}
+
+	return trig;
+
+free_descs:
+	irq_free_descs(trig->subirq_base, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+free_trig:
+	kfree(trig);
+	return NULL;
+}
+
+/**
+ * __iio_trigger_alloc - Allocate a trigger
+ * @parent:		Device to allocate iio_trigger for
+ * @this_mod:		module allocating the trigger
+ * @fmt:		trigger name format. If it includes format
+ *			specifiers, the additional arguments following
+ *			format are formatted and inserted in the resulting
+ *			string replacing their respective specifiers.
+ * RETURNS:
+ * Pointer to allocated iio_trigger on success, NULL on failure.
+ */
+struct iio_trigger *__iio_trigger_alloc(struct device *parent,
+					struct module *this_mod,
+					const char *fmt, ...)
+{
+	struct iio_trigger *trig;
+	va_list vargs;
+
+	va_start(vargs, fmt);
+	trig = viio_trigger_alloc(parent, this_mod, fmt, vargs);
+	va_end(vargs);
+
+	return trig;
+}
+EXPORT_SYMBOL(__iio_trigger_alloc);
+
+void iio_trigger_free(struct iio_trigger *trig)
+{
+	if (trig)
+		put_device(&trig->dev);
+}
+EXPORT_SYMBOL(iio_trigger_free);
+
+static void devm_iio_trigger_release(struct device *dev, void *res)
+{
+	iio_trigger_free(*(struct iio_trigger **)res);
+}
+
+/**
+ * __devm_iio_trigger_alloc - Resource-managed iio_trigger_alloc()
+ * Managed iio_trigger_alloc.  iio_trigger allocated with this function is
+ * automatically freed on driver detach.
+ * @parent:		Device to allocate iio_trigger for
+ * @this_mod:		module allocating the trigger
+ * @fmt:		trigger name format. If it includes format
+ *			specifiers, the additional arguments following
+ *			format are formatted and inserted in the resulting
+ *			string replacing their respective specifiers.
+ *
+ *
+ * RETURNS:
+ * Pointer to allocated iio_trigger on success, NULL on failure.
+ */
+struct iio_trigger *__devm_iio_trigger_alloc(struct device *parent,
+					     struct module *this_mod,
+					     const char *fmt, ...)
+{
+	struct iio_trigger **ptr, *trig;
+	va_list vargs;
+
+	ptr = devres_alloc(devm_iio_trigger_release, sizeof(*ptr),
+			   GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	/* use raw alloc_dr for kmalloc caller tracing */
+	va_start(vargs, fmt);
+	trig = viio_trigger_alloc(parent, this_mod, fmt, vargs);
+	va_end(vargs);
+	if (trig) {
+		*ptr = trig;
+		devres_add(parent, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return trig;
+}
+EXPORT_SYMBOL_GPL(__devm_iio_trigger_alloc);
+
+static void devm_iio_trigger_unreg(void *trigger_info)
+{
+	iio_trigger_unregister(trigger_info);
+}
+
+/**
+ * devm_iio_trigger_register - Resource-managed iio_trigger_register()
+ * @dev:	device this trigger was allocated for
+ * @trig_info:	trigger to register
+ *
+ * Managed iio_trigger_register().  The IIO trigger registered with this
+ * function is automatically unregistered on driver detach. This function
+ * calls iio_trigger_register() internally. Refer to that function for more
+ * information.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int devm_iio_trigger_register(struct device *dev,
+			      struct iio_trigger *trig_info)
+{
+	int ret;
+
+	ret = iio_trigger_register(trig_info);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, devm_iio_trigger_unreg, trig_info);
+}
+EXPORT_SYMBOL_GPL(devm_iio_trigger_register);
+
+bool iio_trigger_using_own(struct iio_dev *indio_dev)
+{
+	return indio_dev->trig->attached_own_device;
+}
+EXPORT_SYMBOL(iio_trigger_using_own);
+
+/**
+ * iio_validate_own_trigger - Check if a trigger and IIO device belong to
+ *  the same device
+ * @idev: the IIO device to check
+ * @trig: the IIO trigger to check
+ *
+ * This function can be used as the validate_trigger callback for triggers that
+ * can only be attached to their own device.
+ *
+ * Return: 0 if both the trigger and the IIO device belong to the same
+ * device, -EINVAL otherwise.
+ */
+int iio_validate_own_trigger(struct iio_dev *idev, struct iio_trigger *trig)
+{
+	if (idev->dev.parent != trig->dev.parent)
+		return -EINVAL;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iio_validate_own_trigger);
+
+/**
+ * iio_trigger_validate_own_device - Check if a trigger and IIO device belong to
+ *  the same device
+ * @trig: The IIO trigger to check
+ * @indio_dev: the IIO device to check
+ *
+ * This function can be used as the validate_device callback for triggers that
+ * can only be attached to their own device.
+ *
+ * Return: 0 if both the trigger and the IIO device belong to the same
+ * device, -EINVAL otherwise.
+ */
+int iio_trigger_validate_own_device(struct iio_trigger *trig,
+				    struct iio_dev *indio_dev)
+{
+	if (indio_dev->dev.parent != trig->dev.parent)
+		return -EINVAL;
+	return 0;
+}
+EXPORT_SYMBOL(iio_trigger_validate_own_device);
+
+int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
+{
+	return iio_device_register_sysfs_group(indio_dev,
+					       &iio_trigger_consumer_attr_group);
+}
+
+void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
+{
+	/* Clean up an associated but not attached trigger reference */
+	if (indio_dev->trig)
+		iio_trigger_put(indio_dev->trig);
+}