mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-21 11:44:01 +08:00
a980e04609
Take the core support + the kfifo buffer implentation out of staging. Whilst we are far from done in improving this subsystem it is now at a stage where the userspae interfaces (provided by the core) can be considered stable. Drivers will follow over a longer time scale. Signed-off-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
454 lines
11 KiB
C
454 lines
11 KiB
C
/* Industrial I/O event handling
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*
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* Copyright (c) 2008 Jonathan Cameron
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* Based on elements of hwmon and input subsystems.
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*/
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#include <linux/anon_inodes.h>
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#include <linux/device.h>
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/kfifo.h>
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#include <linux/module.h>
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#include <linux/poll.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/wait.h>
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#include <linux/iio/iio.h>
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#include "iio_core.h"
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#include <linux/iio/sysfs.h>
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#include <linux/iio/events.h>
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/**
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* struct iio_event_interface - chrdev interface for an event line
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* @wait: wait queue to allow blocking reads of events
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* @det_events: list of detected events
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* @dev_attr_list: list of event interface sysfs attribute
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* @flags: file operations related flags including busy flag.
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* @group: event interface sysfs attribute group
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*/
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struct iio_event_interface {
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wait_queue_head_t wait;
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DECLARE_KFIFO(det_events, struct iio_event_data, 16);
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struct list_head dev_attr_list;
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unsigned long flags;
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struct attribute_group group;
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};
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int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
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{
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struct iio_event_interface *ev_int = indio_dev->event_interface;
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struct iio_event_data ev;
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int copied;
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/* Does anyone care? */
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spin_lock(&ev_int->wait.lock);
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if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
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ev.id = ev_code;
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ev.timestamp = timestamp;
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copied = kfifo_put(&ev_int->det_events, &ev);
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if (copied != 0)
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wake_up_locked_poll(&ev_int->wait, POLLIN);
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}
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spin_unlock(&ev_int->wait.lock);
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return 0;
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}
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EXPORT_SYMBOL(iio_push_event);
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/**
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* iio_event_poll() - poll the event queue to find out if it has data
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*/
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static unsigned int iio_event_poll(struct file *filep,
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struct poll_table_struct *wait)
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{
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struct iio_event_interface *ev_int = filep->private_data;
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unsigned int events = 0;
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poll_wait(filep, &ev_int->wait, wait);
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spin_lock(&ev_int->wait.lock);
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if (!kfifo_is_empty(&ev_int->det_events))
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events = POLLIN | POLLRDNORM;
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spin_unlock(&ev_int->wait.lock);
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return events;
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}
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static ssize_t iio_event_chrdev_read(struct file *filep,
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char __user *buf,
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size_t count,
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loff_t *f_ps)
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{
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struct iio_event_interface *ev_int = filep->private_data;
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unsigned int copied;
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int ret;
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if (count < sizeof(struct iio_event_data))
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return -EINVAL;
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spin_lock(&ev_int->wait.lock);
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if (kfifo_is_empty(&ev_int->det_events)) {
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if (filep->f_flags & O_NONBLOCK) {
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ret = -EAGAIN;
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goto error_unlock;
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}
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/* Blocking on device; waiting for something to be there */
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ret = wait_event_interruptible_locked(ev_int->wait,
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!kfifo_is_empty(&ev_int->det_events));
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if (ret)
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goto error_unlock;
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/* Single access device so no one else can get the data */
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}
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ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
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error_unlock:
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spin_unlock(&ev_int->wait.lock);
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return ret ? ret : copied;
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}
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static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
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{
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struct iio_event_interface *ev_int = filep->private_data;
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spin_lock(&ev_int->wait.lock);
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__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
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/*
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* In order to maintain a clean state for reopening,
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* clear out any awaiting events. The mask will prevent
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* any new __iio_push_event calls running.
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*/
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kfifo_reset_out(&ev_int->det_events);
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spin_unlock(&ev_int->wait.lock);
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return 0;
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}
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static const struct file_operations iio_event_chrdev_fileops = {
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.read = iio_event_chrdev_read,
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.poll = iio_event_poll,
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.release = iio_event_chrdev_release,
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.owner = THIS_MODULE,
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.llseek = noop_llseek,
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};
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int iio_event_getfd(struct iio_dev *indio_dev)
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{
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struct iio_event_interface *ev_int = indio_dev->event_interface;
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int fd;
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if (ev_int == NULL)
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return -ENODEV;
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spin_lock(&ev_int->wait.lock);
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if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
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spin_unlock(&ev_int->wait.lock);
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return -EBUSY;
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}
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spin_unlock(&ev_int->wait.lock);
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fd = anon_inode_getfd("iio:event",
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&iio_event_chrdev_fileops, ev_int, O_RDONLY);
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if (fd < 0) {
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spin_lock(&ev_int->wait.lock);
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__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
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spin_unlock(&ev_int->wait.lock);
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}
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return fd;
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}
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static const char * const iio_ev_type_text[] = {
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[IIO_EV_TYPE_THRESH] = "thresh",
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[IIO_EV_TYPE_MAG] = "mag",
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[IIO_EV_TYPE_ROC] = "roc",
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[IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
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[IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
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};
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static const char * const iio_ev_dir_text[] = {
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[IIO_EV_DIR_EITHER] = "either",
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[IIO_EV_DIR_RISING] = "rising",
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[IIO_EV_DIR_FALLING] = "falling"
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};
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static ssize_t iio_ev_state_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t len)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
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int ret;
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bool val;
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ret = strtobool(buf, &val);
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if (ret < 0)
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return ret;
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ret = indio_dev->info->write_event_config(indio_dev,
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this_attr->address,
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val);
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return (ret < 0) ? ret : len;
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}
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static ssize_t iio_ev_state_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
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int val = indio_dev->info->read_event_config(indio_dev,
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this_attr->address);
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if (val < 0)
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return val;
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else
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return sprintf(buf, "%d\n", val);
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}
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static ssize_t iio_ev_value_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
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int val, ret;
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ret = indio_dev->info->read_event_value(indio_dev,
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this_attr->address, &val);
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if (ret < 0)
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return ret;
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return sprintf(buf, "%d\n", val);
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}
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static ssize_t iio_ev_value_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t len)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
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unsigned long val;
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int ret;
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if (!indio_dev->info->write_event_value)
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return -EINVAL;
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ret = strict_strtoul(buf, 10, &val);
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if (ret)
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return ret;
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ret = indio_dev->info->write_event_value(indio_dev, this_attr->address,
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val);
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if (ret < 0)
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return ret;
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return len;
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}
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static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan)
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{
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int ret = 0, i, attrcount = 0;
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u64 mask = 0;
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char *postfix;
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if (!chan->event_mask)
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return 0;
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for_each_set_bit(i, &chan->event_mask, sizeof(chan->event_mask)*8) {
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postfix = kasprintf(GFP_KERNEL, "%s_%s_en",
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iio_ev_type_text[i/IIO_EV_DIR_MAX],
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iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
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if (postfix == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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if (chan->modified)
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mask = IIO_MOD_EVENT_CODE(chan->type, 0, chan->channel,
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i/IIO_EV_DIR_MAX,
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i%IIO_EV_DIR_MAX);
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else if (chan->differential)
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mask = IIO_EVENT_CODE(chan->type,
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0, 0,
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i%IIO_EV_DIR_MAX,
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i/IIO_EV_DIR_MAX,
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0,
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chan->channel,
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chan->channel2);
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else
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mask = IIO_UNMOD_EVENT_CODE(chan->type,
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chan->channel,
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i/IIO_EV_DIR_MAX,
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i%IIO_EV_DIR_MAX);
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ret = __iio_add_chan_devattr(postfix,
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chan,
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&iio_ev_state_show,
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iio_ev_state_store,
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mask,
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0,
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&indio_dev->dev,
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&indio_dev->event_interface->
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dev_attr_list);
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kfree(postfix);
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if (ret)
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goto error_ret;
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attrcount++;
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postfix = kasprintf(GFP_KERNEL, "%s_%s_value",
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iio_ev_type_text[i/IIO_EV_DIR_MAX],
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iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
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if (postfix == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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ret = __iio_add_chan_devattr(postfix, chan,
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iio_ev_value_show,
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iio_ev_value_store,
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mask,
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0,
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&indio_dev->dev,
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&indio_dev->event_interface->
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dev_attr_list);
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kfree(postfix);
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if (ret)
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goto error_ret;
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attrcount++;
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}
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ret = attrcount;
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error_ret:
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return ret;
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}
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static inline void __iio_remove_event_config_attrs(struct iio_dev *indio_dev)
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{
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struct iio_dev_attr *p, *n;
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list_for_each_entry_safe(p, n,
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&indio_dev->event_interface->
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dev_attr_list, l) {
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kfree(p->dev_attr.attr.name);
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kfree(p);
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}
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}
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static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
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{
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int j, ret, attrcount = 0;
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INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
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/* Dynically created from the channels array */
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for (j = 0; j < indio_dev->num_channels; j++) {
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ret = iio_device_add_event_sysfs(indio_dev,
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&indio_dev->channels[j]);
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if (ret < 0)
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goto error_clear_attrs;
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attrcount += ret;
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}
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return attrcount;
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error_clear_attrs:
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__iio_remove_event_config_attrs(indio_dev);
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return ret;
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}
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static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
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{
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int j;
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for (j = 0; j < indio_dev->num_channels; j++)
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if (indio_dev->channels[j].event_mask != 0)
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return true;
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return false;
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}
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static void iio_setup_ev_int(struct iio_event_interface *ev_int)
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{
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INIT_KFIFO(ev_int->det_events);
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init_waitqueue_head(&ev_int->wait);
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}
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static const char *iio_event_group_name = "events";
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int iio_device_register_eventset(struct iio_dev *indio_dev)
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{
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struct iio_dev_attr *p;
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int ret = 0, attrcount_orig = 0, attrcount, attrn;
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struct attribute **attr;
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if (!(indio_dev->info->event_attrs ||
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iio_check_for_dynamic_events(indio_dev)))
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return 0;
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indio_dev->event_interface =
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kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
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if (indio_dev->event_interface == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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iio_setup_ev_int(indio_dev->event_interface);
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if (indio_dev->info->event_attrs != NULL) {
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attr = indio_dev->info->event_attrs->attrs;
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while (*attr++ != NULL)
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attrcount_orig++;
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}
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attrcount = attrcount_orig;
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if (indio_dev->channels) {
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ret = __iio_add_event_config_attrs(indio_dev);
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if (ret < 0)
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goto error_free_setup_event_lines;
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attrcount += ret;
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}
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indio_dev->event_interface->group.name = iio_event_group_name;
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indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
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sizeof(indio_dev->event_interface->group.attrs[0]),
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GFP_KERNEL);
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if (indio_dev->event_interface->group.attrs == NULL) {
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ret = -ENOMEM;
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goto error_free_setup_event_lines;
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}
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if (indio_dev->info->event_attrs)
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memcpy(indio_dev->event_interface->group.attrs,
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indio_dev->info->event_attrs->attrs,
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sizeof(indio_dev->event_interface->group.attrs[0])
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*attrcount_orig);
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attrn = attrcount_orig;
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/* Add all elements from the list. */
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list_for_each_entry(p,
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&indio_dev->event_interface->dev_attr_list,
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l)
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indio_dev->event_interface->group.attrs[attrn++] =
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&p->dev_attr.attr;
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indio_dev->groups[indio_dev->groupcounter++] =
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&indio_dev->event_interface->group;
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return 0;
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error_free_setup_event_lines:
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__iio_remove_event_config_attrs(indio_dev);
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kfree(indio_dev->event_interface);
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error_ret:
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return ret;
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}
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void iio_device_unregister_eventset(struct iio_dev *indio_dev)
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{
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if (indio_dev->event_interface == NULL)
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return;
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__iio_remove_event_config_attrs(indio_dev);
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kfree(indio_dev->event_interface->group.attrs);
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kfree(indio_dev->event_interface);
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}
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