| /* 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", |
| }; |
| |
| 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; |
| postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", |
| iio_ev_type_text[type], iio_ev_dir_text[dir], |
| 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) |
| 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; |
| |
| /* 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) |
| 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); |
| 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); |
| } |