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linux/drivers/iio/industrialio-event.c
Stefani Seibold 498d319bb5 kfifo API type safety 
This patch enhances the type safety for the kfifo API.  It is now safe
to put const data into a non const FIFO and the API will now generate a
compiler warning when reading from the fifo where the destination
address is pointing to a const variable.

As a side effect the kfifo_put() does now expect the value of an element
instead a pointer to the element.  This was suggested Russell King.  It
make the handling of the kfifo_put easier since there is no need to
create a helper variable for getting the address of a pointer or to pass
integers of different sizes.

IMHO the API break is okay, since there are currently only six users of
kfifo_put().

The code is also cleaner by kicking out the "if (0)" expressions.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-15 09:32:23 +09:00

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/* 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;
};
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;
unsigned long flags;
int copied;
/* Does anyone care? */
spin_lock_irqsave(&ev_int->wait.lock, flags);
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_locked_poll(&ev_int->wait, POLLIN);
}
spin_unlock_irqrestore(&ev_int->wait.lock, flags);
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);
spin_lock_irq(&ev_int->wait.lock);
if (!kfifo_is_empty(&ev_int->det_events))
events = POLLIN | POLLRDNORM;
spin_unlock_irq(&ev_int->wait.lock);
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;
spin_lock_irq(&ev_int->wait.lock);
if (kfifo_is_empty(&ev_int->det_events)) {
if (filep->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
goto error_unlock;
}
/* Blocking on device; waiting for something to be there */
ret = wait_event_interruptible_locked_irq(ev_int->wait,
!kfifo_is_empty(&ev_int->det_events) ||
indio_dev->info == NULL);
if (ret)
goto error_unlock;
if (indio_dev->info == NULL) {
ret = -ENODEV;
goto error_unlock;
}
/* Single access device so no one else can get the data */
}
ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
error_unlock:
spin_unlock_irq(&ev_int->wait.lock);
return ret ? ret : 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;
spin_lock_irq(&ev_int->wait.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.
*/
kfifo_reset_out(&ev_int->det_events);
spin_unlock_irq(&ev_int->wait.lock);
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;
spin_lock_irq(&ev_int->wait.lock);
if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
spin_unlock_irq(&ev_int->wait.lock);
return -EBUSY;
}
spin_unlock_irq(&ev_int->wait.lock);
iio_device_get(indio_dev);
fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
indio_dev, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
spin_lock_irq(&ev_int->wait.lock);
__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
spin_unlock_irq(&ev_int->wait.lock);
iio_device_put(indio_dev);
}
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",
};
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;
if (indio_dev->info->write_event_config)
ret = indio_dev->info->write_event_config(indio_dev,
this_attr->address, val);
else
ret = indio_dev->info->write_event_config_new(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;
if (indio_dev->info->read_event_config)
val = indio_dev->info->read_event_config(indio_dev,
this_attr->address);
else
val = indio_dev->info->read_event_config_new(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;
int ret;
if (indio_dev->info->read_event_value) {
ret = indio_dev->info->read_event_value(indio_dev,
this_attr->address, &val);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", val);
} else {
ret = indio_dev->info->read_event_value_new(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 iio_format_value(buf, ret, val, val2);
}
}
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 &&
!indio_dev->info->write_event_value_new)
return -EINVAL;
if (indio_dev->info->write_event_value) {
ret = kstrtoint(buf, 10, &val);
if (ret)
return ret;
ret = indio_dev->info->write_event_value(indio_dev,
this_attr->address, val);
} else {
ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
if (ret)
return ret;
ret = indio_dev->info->write_event_value_new(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)) {
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_new(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)
goto error_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)
goto error_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)
goto error_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)
goto error_ret;
attrcount += ret;
}
ret = attrcount;
error_ret:
return ret;
}
static int iio_device_add_event_sysfs_old(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->channel2,
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 int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan)
{
if (chan->event_mask)
return iio_device_add_event_sysfs_old(indio_dev, chan);
else
return iio_device_add_event_sysfs_new(indio_dev, chan);
}
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].event_mask != 0)
return true;
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);
}
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;
}
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);
error_ret:
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);
}
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