Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 557 insertions, 0 deletions

diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
new file mode 100644
index 000000000..c6dfdf0aa
--- /dev/null
+++ b/drivers/iio/industrialio-event.c
@@ -0,0 +1,557 @@
+/* Industrial I/O event handling
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * Based on elements of hwmon and input subsystems.
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include <linux/iio/iio.h>
+#include "iio_core.h"
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+/**
+ * struct iio_event_interface - chrdev interface for an event line
+ * @wait:		wait queue to allow blocking reads of events
+ * @det_events:		list of detected events
+ * @dev_attr_list:	list of event interface sysfs attribute
+ * @flags:		file operations related flags including busy flag.
+ * @group:		event interface sysfs attribute group
+ * @read_lock:		lock to protect kfifo read operations
+ */
+struct iio_event_interface {
+	wait_queue_head_t	wait;
+	DECLARE_KFIFO(det_events, struct iio_event_data, 16);
+
+	struct list_head	dev_attr_list;
+	unsigned long		flags;
+	struct attribute_group	group;
+	struct mutex		read_lock;
+};
+
+bool iio_event_enabled(const struct iio_event_interface *ev_int)
+{
+	return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
+}
+
+/**
+ * iio_push_event() - try to add event to the list for userspace reading
+ * @indio_dev:		IIO device structure
+ * @ev_code:		What event
+ * @timestamp:		When the event occurred
+ *
+ * Note: The caller must make sure that this function is not running
+ * concurrently for the same indio_dev more than once.
+ *
+ * This function may be safely used as soon as a valid reference to iio_dev has
+ * been obtained via iio_device_alloc(), but any events that are submitted
+ * before iio_device_register() has successfully completed will be silently
+ * discarded.
+ **/
+int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
+{
+	struct iio_event_interface *ev_int = indio_dev->event_interface;
+	struct iio_event_data ev;
+	int copied;
+
+	if (!ev_int)
+		return 0;
+
+	/* Does anyone care? */
+	if (iio_event_enabled(ev_int)) {
+
+		ev.id = ev_code;
+		ev.timestamp = timestamp;
+
+		copied = kfifo_put(&ev_int->det_events, ev);
+		if (copied != 0)
+			wake_up_poll(&ev_int->wait, EPOLLIN);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(iio_push_event);
+
+/**
+ * iio_event_poll() - poll the event queue to find out if it has data
+ * @filep:	File structure pointer to identify the device
+ * @wait:	Poll table pointer to add the wait queue on
+ *
+ * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
+ *	   or a negative error code on failure
+ */
+static __poll_t iio_event_poll(struct file *filep,
+			     struct poll_table_struct *wait)
+{
+	struct iio_dev *indio_dev = filep->private_data;
+	struct iio_event_interface *ev_int = indio_dev->event_interface;
+	__poll_t events = 0;
+
+	if (!indio_dev->info)
+		return events;
+
+	poll_wait(filep, &ev_int->wait, wait);
+
+	if (!kfifo_is_empty(&ev_int->det_events))
+		events = EPOLLIN | EPOLLRDNORM;
+
+	return events;
+}
+
+static ssize_t iio_event_chrdev_read(struct file *filep,
+				     char __user *buf,
+				     size_t count,
+				     loff_t *f_ps)
+{
+	struct iio_dev *indio_dev = filep->private_data;
+	struct iio_event_interface *ev_int = indio_dev->event_interface;
+	unsigned int copied;
+	int ret;
+
+	if (!indio_dev->info)
+		return -ENODEV;
+
+	if (count < sizeof(struct iio_event_data))
+		return -EINVAL;
+
+	do {
+		if (kfifo_is_empty(&ev_int->det_events)) {
+			if (filep->f_flags & O_NONBLOCK)
+				return -EAGAIN;
+
+			ret = wait_event_interruptible(ev_int->wait,
+					!kfifo_is_empty(&ev_int->det_events) ||
+					indio_dev->info == NULL);
+			if (ret)
+				return ret;
+			if (indio_dev->info == NULL)
+				return -ENODEV;
+		}
+
+		if (mutex_lock_interruptible(&ev_int->read_lock))
+			return -ERESTARTSYS;
+		ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
+		mutex_unlock(&ev_int->read_lock);
+
+		if (ret)
+			return ret;
+
+		/*
+		 * If we couldn't read anything from the fifo (a different
+		 * thread might have been faster) we either return -EAGAIN if
+		 * the file descriptor is non-blocking, otherwise we go back to
+		 * sleep and wait for more data to arrive.
+		 */
+		if (copied == 0 && (filep->f_flags & O_NONBLOCK))
+			return -EAGAIN;
+
+	} while (copied == 0);
+
+	return copied;
+}
+
+static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
+{
+	struct iio_dev *indio_dev = filep->private_data;
+	struct iio_event_interface *ev_int = indio_dev->event_interface;
+
+	clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
+
+	iio_device_put(indio_dev);
+
+	return 0;
+}
+
+static const struct file_operations iio_event_chrdev_fileops = {
+	.read =  iio_event_chrdev_read,
+	.poll =  iio_event_poll,
+	.release = iio_event_chrdev_release,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+};
+
+int iio_event_getfd(struct iio_dev *indio_dev)
+{
+	struct iio_event_interface *ev_int = indio_dev->event_interface;
+	int fd;
+
+	if (ev_int == NULL)
+		return -ENODEV;
+
+	fd = mutex_lock_interruptible(&indio_dev->mlock);
+	if (fd)
+		return fd;
+
+	if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
+		fd = -EBUSY;
+		goto unlock;
+	}
+
+	iio_device_get(indio_dev);
+
+	fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
+				indio_dev, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
+		iio_device_put(indio_dev);
+	} else {
+		kfifo_reset_out(&ev_int->det_events);
+	}
+
+unlock:
+	mutex_unlock(&indio_dev->mlock);
+	return fd;
+}
+
+static const char * const iio_ev_type_text[] = {
+	[IIO_EV_TYPE_THRESH] = "thresh",
+	[IIO_EV_TYPE_MAG] = "mag",
+	[IIO_EV_TYPE_ROC] = "roc",
+	[IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
+	[IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
+	[IIO_EV_TYPE_CHANGE] = "change",
+};
+
+static const char * const iio_ev_dir_text[] = {
+	[IIO_EV_DIR_EITHER] = "either",
+	[IIO_EV_DIR_RISING] = "rising",
+	[IIO_EV_DIR_FALLING] = "falling"
+};
+
+static const char * const iio_ev_info_text[] = {
+	[IIO_EV_INFO_ENABLE] = "en",
+	[IIO_EV_INFO_VALUE] = "value",
+	[IIO_EV_INFO_HYSTERESIS] = "hysteresis",
+	[IIO_EV_INFO_PERIOD] = "period",
+	[IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db",
+	[IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db",
+};
+
+static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
+{
+	return attr->c->event_spec[attr->address & 0xffff].dir;
+}
+
+static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
+{
+	return attr->c->event_spec[attr->address & 0xffff].type;
+}
+
+static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
+{
+	return (attr->address >> 16) & 0xffff;
+}
+
+static ssize_t iio_ev_state_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int ret;
+	bool val;
+
+	ret = strtobool(buf, &val);
+	if (ret < 0)
+		return ret;
+
+	ret = indio_dev->info->write_event_config(indio_dev,
+		this_attr->c, iio_ev_attr_type(this_attr),
+		iio_ev_attr_dir(this_attr), val);
+
+	return (ret < 0) ? ret : len;
+}
+
+static ssize_t iio_ev_state_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int val;
+
+	val = indio_dev->info->read_event_config(indio_dev,
+		this_attr->c, iio_ev_attr_type(this_attr),
+		iio_ev_attr_dir(this_attr));
+	if (val < 0)
+		return val;
+	else
+		return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t iio_ev_value_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int val, val2, val_arr[2];
+	int ret;
+
+	ret = indio_dev->info->read_event_value(indio_dev,
+		this_attr->c, iio_ev_attr_type(this_attr),
+		iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
+		&val, &val2);
+	if (ret < 0)
+		return ret;
+	val_arr[0] = val;
+	val_arr[1] = val2;
+	return iio_format_value(buf, ret, 2, val_arr);
+}
+
+static ssize_t iio_ev_value_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int val, val2;
+	int ret;
+
+	if (!indio_dev->info->write_event_value)
+		return -EINVAL;
+
+	ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
+	if (ret)
+		return ret;
+	ret = indio_dev->info->write_event_value(indio_dev,
+		this_attr->c, iio_ev_attr_type(this_attr),
+		iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
+		val, val2);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static int iio_device_add_event(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan, unsigned int spec_index,
+	enum iio_event_type type, enum iio_event_direction dir,
+	enum iio_shared_by shared_by, const unsigned long *mask)
+{
+	ssize_t (*show)(struct device *, struct device_attribute *, char *);
+	ssize_t (*store)(struct device *, struct device_attribute *,
+		const char *, size_t);
+	unsigned int attrcount = 0;
+	unsigned int i;
+	char *postfix;
+	int ret;
+
+	for_each_set_bit(i, mask, sizeof(*mask)*8) {
+		if (i >= ARRAY_SIZE(iio_ev_info_text))
+			return -EINVAL;
+		if (dir != IIO_EV_DIR_NONE)
+			postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
+					iio_ev_type_text[type],
+					iio_ev_dir_text[dir],
+					iio_ev_info_text[i]);
+		else
+			postfix = kasprintf(GFP_KERNEL, "%s_%s",
+					iio_ev_type_text[type],
+					iio_ev_info_text[i]);
+		if (postfix == NULL)
+			return -ENOMEM;
+
+		if (i == IIO_EV_INFO_ENABLE) {
+			show = iio_ev_state_show;
+			store = iio_ev_state_store;
+		} else {
+			show = iio_ev_value_show;
+			store = iio_ev_value_store;
+		}
+
+		ret = __iio_add_chan_devattr(postfix, chan, show, store,
+			 (i << 16) | spec_index, shared_by, &indio_dev->dev,
+			&indio_dev->event_interface->dev_attr_list);
+		kfree(postfix);
+
+		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
+			continue;
+
+		if (ret)
+			return ret;
+
+		attrcount++;
+	}
+
+	return attrcount;
+}
+
+static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan)
+{
+	int ret = 0, i, attrcount = 0;
+	enum iio_event_direction dir;
+	enum iio_event_type type;
+
+	for (i = 0; i < chan->num_event_specs; i++) {
+		type = chan->event_spec[i].type;
+		dir = chan->event_spec[i].dir;
+
+		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
+			IIO_SEPARATE, &chan->event_spec[i].mask_separate);
+		if (ret < 0)
+			return ret;
+		attrcount += ret;
+
+		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
+			IIO_SHARED_BY_TYPE,
+			&chan->event_spec[i].mask_shared_by_type);
+		if (ret < 0)
+			return ret;
+		attrcount += ret;
+
+		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
+			IIO_SHARED_BY_DIR,
+			&chan->event_spec[i].mask_shared_by_dir);
+		if (ret < 0)
+			return ret;
+		attrcount += ret;
+
+		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
+			IIO_SHARED_BY_ALL,
+			&chan->event_spec[i].mask_shared_by_all);
+		if (ret < 0)
+			return ret;
+		attrcount += ret;
+	}
+	ret = attrcount;
+	return ret;
+}
+
+static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
+{
+	int j, ret, attrcount = 0;
+
+	/* Dynamically created from the channels array */
+	for (j = 0; j < indio_dev->num_channels; j++) {
+		ret = iio_device_add_event_sysfs(indio_dev,
+						 &indio_dev->channels[j]);
+		if (ret < 0)
+			return ret;
+		attrcount += ret;
+	}
+	return attrcount;
+}
+
+static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
+{
+	int j;
+
+	for (j = 0; j < indio_dev->num_channels; j++) {
+		if (indio_dev->channels[j].num_event_specs != 0)
+			return true;
+	}
+	return false;
+}
+
+static void iio_setup_ev_int(struct iio_event_interface *ev_int)
+{
+	INIT_KFIFO(ev_int->det_events);
+	init_waitqueue_head(&ev_int->wait);
+	mutex_init(&ev_int->read_lock);
+}
+
+static const char *iio_event_group_name = "events";
+int iio_device_register_eventset(struct iio_dev *indio_dev)
+{
+	struct iio_dev_attr *p;
+	int ret = 0, attrcount_orig = 0, attrcount, attrn;
+	struct attribute **attr;
+
+	if (!(indio_dev->info->event_attrs ||
+	      iio_check_for_dynamic_events(indio_dev)))
+		return 0;
+
+	indio_dev->event_interface =
+		kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
+	if (indio_dev->event_interface == NULL)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
+
+	iio_setup_ev_int(indio_dev->event_interface);
+	if (indio_dev->info->event_attrs != NULL) {
+		attr = indio_dev->info->event_attrs->attrs;
+		while (*attr++ != NULL)
+			attrcount_orig++;
+	}
+	attrcount = attrcount_orig;
+	if (indio_dev->channels) {
+		ret = __iio_add_event_config_attrs(indio_dev);
+		if (ret < 0)
+			goto error_free_setup_event_lines;
+		attrcount += ret;
+	}
+
+	indio_dev->event_interface->group.name = iio_event_group_name;
+	indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
+							  sizeof(indio_dev->event_interface->group.attrs[0]),
+							  GFP_KERNEL);
+	if (indio_dev->event_interface->group.attrs == NULL) {
+		ret = -ENOMEM;
+		goto error_free_setup_event_lines;
+	}
+	if (indio_dev->info->event_attrs)
+		memcpy(indio_dev->event_interface->group.attrs,
+		       indio_dev->info->event_attrs->attrs,
+		       sizeof(indio_dev->event_interface->group.attrs[0])
+		       *attrcount_orig);
+	attrn = attrcount_orig;
+	/* Add all elements from the list. */
+	list_for_each_entry(p,
+			    &indio_dev->event_interface->dev_attr_list,
+			    l)
+		indio_dev->event_interface->group.attrs[attrn++] =
+			&p->dev_attr.attr;
+	indio_dev->groups[indio_dev->groupcounter++] =
+		&indio_dev->event_interface->group;
+
+	return 0;
+
+error_free_setup_event_lines:
+	iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
+	kfree(indio_dev->event_interface);
+	indio_dev->event_interface = NULL;
+	return ret;
+}
+
+/**
+ * iio_device_wakeup_eventset - Wakes up the event waitqueue
+ * @indio_dev: The IIO device
+ *
+ * Wakes up the event waitqueue used for poll() and blocking read().
+ * Should usually be called when the device is unregistered.
+ */
+void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
+{
+	if (indio_dev->event_interface == NULL)
+		return;
+	wake_up(&indio_dev->event_interface->wait);
+}
+
+void iio_device_unregister_eventset(struct iio_dev *indio_dev)
+{
+	if (indio_dev->event_interface == NULL)
+		return;
+	iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
+	kfree(indio_dev->event_interface->group.attrs);
+	kfree(indio_dev->event_interface);
+}