--- /dev/null
+/* 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
+ */
+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;
+};
+
+/**
+ * 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.
+ **/
+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;
+
+ /* Does anyone care? */
+ if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
+
+ ev.id = ev_code;
+ ev.timestamp = timestamp;
+
+ copied = kfifo_put(&ev_int->det_events, ev);
+ if (copied != 0)
+ wake_up_poll(&ev_int->wait, POLLIN);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(iio_push_event);
+
+/**
+ * iio_event_poll() - poll the event queue to find out if it has data
+ */
+static unsigned int 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;
+ unsigned int events = 0;
+
+ if (!indio_dev->info)
+ return -ENODEV;
+
+ poll_wait(filep, &ev_int->wait, wait);
+
+ if (!kfifo_is_empty(&ev_int->det_events))
+ events = POLLIN | POLLRDNORM;
+
+ 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;
+
+ if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags))
+ return -EBUSY;
+
+ 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);
+ }
+
+ 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",
+};
+
+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);
+}
Code Review / kvmfornfv.git / blobdiff