staging:iio: Factor out event handling into its own file

The core iio file has gotten quite cluttered over time. This patch moves
the event handling code into its own file. Since the event handling code is
largely independent from the core code the only code changes necessary for
this are to make the moved iio_device_register_eventset,
iio_device_unregister_eventset and iio_event_getfd functions non static.

This has also the advantage that industrialio-core.c is now closer again to
its counterpart in the outofstaging branch.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 483 insertions, 0 deletions

diff --git a/drivers/staging/iio/industrialio-event.c b/drivers/staging/iio/industrialio-event.c
new file mode 100644
index 000000000000..a7b345ddc257
--- /dev/null
+++ b/drivers/staging/iio/industrialio-event.c
@@ -0,0 +1,483 @@
+/* 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/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include "iio.h"
+#include "iio_core.h"
+#include "sysfs.h"
+#include "events.h"
+
+/**
+ * struct iio_detected_event_list - list element for events that have occurred
+ * @list:		linked list header
+ * @ev:			the event itself
+ */
+struct iio_detected_event_list {
+	struct list_head		list;
+	struct iio_event_data		ev;
+};
+
+/**
+ * struct iio_event_interface - chrdev interface for an event line
+ * @wait:		wait queue to allow blocking reads of events
+ * @event_list_lock:	mutex to protect the list of detected events
+ * @det_events:		list of detected events
+ * @max_events:		maximum number of events before new ones are dropped
+ * @current_events:	number of events in detected list
+ * @dev_attr_list:	list of event interface sysfs attribute
+ * @flags:		file operations related flags including busy flag.
+ * @group:		event interface sysfs attribute group
+ */
+struct iio_event_interface {
+	wait_queue_head_t	wait;
+	struct mutex		event_list_lock;
+	struct list_head	det_events;
+	int			max_events;
+	int			current_events;
+	struct list_head	dev_attr_list;
+	unsigned long		flags;
+	struct attribute_group	group;
+};
+
+int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
+{
+	struct iio_event_interface *ev_int = indio_dev->event_interface;
+	struct iio_detected_event_list *ev;
+	int ret = 0;
+
+	/* Does anyone care? */
+	mutex_lock(&ev_int->event_list_lock);
+	if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
+		if (ev_int->current_events == ev_int->max_events) {
+			mutex_unlock(&ev_int->event_list_lock);
+			return 0;
+		}
+		ev = kmalloc(sizeof(*ev), GFP_KERNEL);
+		if (ev == NULL) {
+			ret = -ENOMEM;
+			mutex_unlock(&ev_int->event_list_lock);
+			goto error_ret;
+		}
+		ev->ev.id = ev_code;
+		ev->ev.timestamp = timestamp;
+
+		list_add_tail(&ev->list, &ev_int->det_events);
+		ev_int->current_events++;
+		mutex_unlock(&ev_int->event_list_lock);
+		wake_up_interruptible(&ev_int->wait);
+	} else
+		mutex_unlock(&ev_int->event_list_lock);
+
+error_ret:
+	return ret;
+}
+EXPORT_SYMBOL(iio_push_event);
+
+static ssize_t iio_event_chrdev_read(struct file *filep,
+				     char __user *buf,
+				     size_t count,
+				     loff_t *f_ps)
+{
+	struct iio_event_interface *ev_int = filep->private_data;
+	struct iio_detected_event_list *el;
+	size_t len = sizeof(el->ev);
+	int ret;
+
+	if (count < len)
+		return -EINVAL;
+
+	mutex_lock(&ev_int->event_list_lock);
+	if (list_empty(&ev_int->det_events)) {
+		if (filep->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
+			goto error_mutex_unlock;
+		}
+		mutex_unlock(&ev_int->event_list_lock);
+		/* Blocking on device; waiting for something to be there */
+		ret = wait_event_interruptible(ev_int->wait,
+					       !list_empty(&ev_int
+							   ->det_events));
+		if (ret)
+			goto error_ret;
+		/* Single access device so no one else can get the data */
+		mutex_lock(&ev_int->event_list_lock);
+	}
+
+	el = list_first_entry(&ev_int->det_events,
+			      struct iio_detected_event_list,
+			      list);
+	if (copy_to_user(buf, &(el->ev), len)) {
+		ret = -EFAULT;
+		goto error_mutex_unlock;
+	}
+	list_del(&el->list);
+	ev_int->current_events--;
+	mutex_unlock(&ev_int->event_list_lock);
+	kfree(el);
+
+	return len;
+
+error_mutex_unlock:
+	mutex_unlock(&ev_int->event_list_lock);
+error_ret:
+
+	return ret;
+}
+
+static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
+{
+	struct iio_event_interface *ev_int = filep->private_data;
+	struct iio_detected_event_list *el, *t;
+
+	mutex_lock(&ev_int->event_list_lock);
+	clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
+	/*
+	 * In order to maintain a clean state for reopening,
+	 * clear out any awaiting events. The mask will prevent
+	 * any new __iio_push_event calls running.
+	 */
+	list_for_each_entry_safe(el, t, &ev_int->det_events, list) {
+		list_del(&el->list);
+		kfree(el);
+	}
+	ev_int->current_events = 0;
+	mutex_unlock(&ev_int->event_list_lock);
+
+	return 0;
+}
+
+static const struct file_operations iio_event_chrdev_fileops = {
+	.read =  iio_event_chrdev_read,
+	.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;
+
+	mutex_lock(&ev_int->event_list_lock);
+	if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
+		mutex_unlock(&ev_int->event_list_lock);
+		return -EBUSY;
+	}
+	mutex_unlock(&ev_int->event_list_lock);
+	fd = anon_inode_getfd("iio:event",
+				&iio_event_chrdev_fileops, ev_int, O_RDONLY);
+	if (fd < 0) {
+		mutex_lock(&ev_int->event_list_lock);
+		clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
+		mutex_unlock(&ev_int->event_list_lock);
+	}
+	return fd;
+}
+
+static const char * const iio_ev_type_text[] = {
+	[IIO_EV_TYPE_THRESH] = "thresh",
+	[IIO_EV_TYPE_MAG] = "mag",
+	[IIO_EV_TYPE_ROC] = "roc",
+	[IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
+	[IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
+};
+
+static const char * const iio_ev_dir_text[] = {
+	[IIO_EV_DIR_EITHER] = "either",
+	[IIO_EV_DIR_RISING] = "rising",
+	[IIO_EV_DIR_FALLING] = "falling"
+};
+
+static ssize_t iio_ev_state_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int ret;
+	bool val;
+
+	ret = strtobool(buf, &val);
+	if (ret < 0)
+		return ret;
+
+	ret = indio_dev->info->write_event_config(indio_dev,
+						  this_attr->address,
+						  val);
+	return (ret < 0) ? ret : len;
+}
+
+static ssize_t iio_ev_state_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int val = indio_dev->info->read_event_config(indio_dev,
+						     this_attr->address);
+
+	if (val < 0)
+		return val;
+	else
+		return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t iio_ev_value_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int val, ret;
+
+	ret = indio_dev->info->read_event_value(indio_dev,
+						this_attr->address, &val);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t iio_ev_value_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	unsigned long val;
+	int ret;
+
+	if (!indio_dev->info->write_event_value)
+		return -EINVAL;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	ret = indio_dev->info->write_event_value(indio_dev, this_attr->address,
+						 val);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
+				      struct iio_chan_spec const *chan)
+{
+	int ret = 0, i, attrcount = 0;
+	u64 mask = 0;
+	char *postfix;
+	if (!chan->event_mask)
+		return 0;
+
+	for_each_set_bit(i, &chan->event_mask, sizeof(chan->event_mask)*8) {
+		postfix = kasprintf(GFP_KERNEL, "%s_%s_en",
+				    iio_ev_type_text[i/IIO_EV_DIR_MAX],
+				    iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
+		if (postfix == NULL) {
+			ret = -ENOMEM;
+			goto error_ret;
+		}
+		if (chan->modified)
+			mask = IIO_MOD_EVENT_CODE(chan->type, 0, chan->channel,
+						  i/IIO_EV_DIR_MAX,
+						  i%IIO_EV_DIR_MAX);
+		else if (chan->differential)
+			mask = IIO_EVENT_CODE(chan->type,
+					      0, 0,
+					      i%IIO_EV_DIR_MAX,
+					      i/IIO_EV_DIR_MAX,
+					      0,
+					      chan->channel,
+					      chan->channel2);
+		else
+			mask = IIO_UNMOD_EVENT_CODE(chan->type,
+						    chan->channel,
+						    i/IIO_EV_DIR_MAX,
+						    i%IIO_EV_DIR_MAX);
+
+		ret = __iio_add_chan_devattr(postfix,
+					     chan,
+					     &iio_ev_state_show,
+					     iio_ev_state_store,
+					     mask,
+					     0,
+					     &indio_dev->dev,
+					     &indio_dev->event_interface->
+					     dev_attr_list);
+		kfree(postfix);
+		if (ret)
+			goto error_ret;
+		attrcount++;
+		postfix = kasprintf(GFP_KERNEL, "%s_%s_value",
+				    iio_ev_type_text[i/IIO_EV_DIR_MAX],
+				    iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
+		if (postfix == NULL) {
+			ret = -ENOMEM;
+			goto error_ret;
+		}
+		ret = __iio_add_chan_devattr(postfix, chan,
+					     iio_ev_value_show,
+					     iio_ev_value_store,
+					     mask,
+					     0,
+					     &indio_dev->dev,
+					     &indio_dev->event_interface->
+					     dev_attr_list);
+		kfree(postfix);
+		if (ret)
+			goto error_ret;
+		attrcount++;
+	}
+	ret = attrcount;
+error_ret:
+	return ret;
+}
+
+static inline void __iio_remove_event_config_attrs(struct iio_dev *indio_dev)
+{
+	struct iio_dev_attr *p, *n;
+	list_for_each_entry_safe(p, n,
+				 &indio_dev->event_interface->
+				 dev_attr_list, l) {
+		kfree(p->dev_attr.attr.name);
+		kfree(p);
+	}
+}
+
+static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
+{
+	int j, ret, attrcount = 0;
+
+	INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
+	/* Dynically created from the channels array */
+	for (j = 0; j < indio_dev->num_channels; j++) {
+		ret = iio_device_add_event_sysfs(indio_dev,
+						 &indio_dev->channels[j]);
+		if (ret < 0)
+			goto error_clear_attrs;
+		attrcount += ret;
+	}
+	return attrcount;
+
+error_clear_attrs:
+	__iio_remove_event_config_attrs(indio_dev);
+
+	return ret;
+}
+
+static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
+{
+	int j;
+
+	for (j = 0; j < indio_dev->num_channels; j++)
+		if (indio_dev->channels[j].event_mask != 0)
+			return true;
+	return false;
+}
+
+static void iio_setup_ev_int(struct iio_event_interface *ev_int)
+{
+	mutex_init(&ev_int->event_list_lock);
+	/* discussion point - make this variable? */
+	ev_int->max_events = 10;
+	ev_int->current_events = 0;
+	INIT_LIST_HEAD(&ev_int->det_events);
+	init_waitqueue_head(&ev_int->wait);
+}
+
+static const char *iio_event_group_name = "events";
+int iio_device_register_eventset(struct iio_dev *indio_dev)
+{
+	struct iio_dev_attr *p;
+	int ret = 0, attrcount_orig = 0, attrcount, attrn;
+	struct attribute **attr;
+
+	if (!(indio_dev->info->event_attrs ||
+	      iio_check_for_dynamic_events(indio_dev)))
+		return 0;
+
+	indio_dev->event_interface =
+		kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
+	if (indio_dev->event_interface == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	iio_setup_ev_int(indio_dev->event_interface);
+	if (indio_dev->info->event_attrs != NULL) {
+		attr = indio_dev->info->event_attrs->attrs;
+		while (*attr++ != NULL)
+			attrcount_orig++;
+	}
+	attrcount = attrcount_orig;
+	if (indio_dev->channels) {
+		ret = __iio_add_event_config_attrs(indio_dev);
+		if (ret < 0)
+			goto error_free_setup_event_lines;
+		attrcount += ret;
+	}
+
+	indio_dev->event_interface->group.name = iio_event_group_name;
+	indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
+							  sizeof(indio_dev->event_interface->group.attrs[0]),
+							  GFP_KERNEL);
+	if (indio_dev->event_interface->group.attrs == NULL) {
+		ret = -ENOMEM;
+		goto error_free_setup_event_lines;
+	}
+	if (indio_dev->info->event_attrs)
+		memcpy(indio_dev->event_interface->group.attrs,
+		       indio_dev->info->event_attrs->attrs,
+		       sizeof(indio_dev->event_interface->group.attrs[0])
+		       *attrcount_orig);
+	attrn = attrcount_orig;
+	/* Add all elements from the list. */
+	list_for_each_entry(p,
+			    &indio_dev->event_interface->dev_attr_list,
+			    l)
+		indio_dev->event_interface->group.attrs[attrn++] =
+			&p->dev_attr.attr;
+	indio_dev->groups[indio_dev->groupcounter++] =
+		&indio_dev->event_interface->group;
+
+	return 0;
+
+error_free_setup_event_lines:
+	__iio_remove_event_config_attrs(indio_dev);
+	kfree(indio_dev->event_interface);
+error_ret:
+
+	return ret;
+}
+
+void iio_device_unregister_eventset(struct iio_dev *indio_dev)
+{
+	if (indio_dev->event_interface == NULL)
+		return;
+	__iio_remove_event_config_attrs(indio_dev);
+	kfree(indio_dev->event_interface->group.attrs);
+	kfree(indio_dev->event_interface);
+}