Input: add support for polling to input devices

Separating "normal" and "polled" input devices was a mistake, as often we
want to allow the very same device work on both interrupt-driven and
polled mode, depending on the board on which the device is used.

This introduces new APIs:

- input_setup_polling
- input_set_poll_interval
- input_set_min_poll_interval
- input_set_max_poll_interval

These new APIs allow switching an input device into polled mode with sysfs
attributes matching drivers using input_polled_dev APIs that will be
eventually removed.

Tested-by: Michal Vokáč <michal.vokac@ysoft.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Dmitry Torokhov 2017-04-18 17:28:30 -07:00
parent 2da9d2b5b9
commit e95656ea15
5 changed files with 273 additions and 8 deletions

View File

@ -6,7 +6,7 @@
# Each configuration option enables a list of files.
obj-$(CONFIG_INPUT) += input-core.o
input-core-y := input.o input-compat.o input-mt.o ff-core.o
input-core-y := input.o input-compat.o input-mt.o input-poller.o ff-core.o
obj-$(CONFIG_INPUT_FF_MEMLESS) += ff-memless.o
obj-$(CONFIG_INPUT_POLLDEV) += input-polldev.o

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@ -0,0 +1,213 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Support for polling mode for input devices.
*/
#include <linux/device.h>
#include <linux/input.h>
#include <linux/jiffies.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include "input-poller.h"
struct input_dev_poller {
void (*poll)(struct input_dev *dev);
unsigned int poll_interval; /* msec */
unsigned int poll_interval_max; /* msec */
unsigned int poll_interval_min; /* msec */
struct input_dev *input;
struct delayed_work work;
};
static void input_dev_poller_queue_work(struct input_dev_poller *poller)
{
unsigned long delay;
delay = msecs_to_jiffies(poller->poll_interval);
if (delay >= HZ)
delay = round_jiffies_relative(delay);
queue_delayed_work(system_freezable_wq, &poller->work, delay);
}
static void input_dev_poller_work(struct work_struct *work)
{
struct input_dev_poller *poller =
container_of(work, struct input_dev_poller, work.work);
poller->poll(poller->input);
input_dev_poller_queue_work(poller);
}
void input_dev_poller_finalize(struct input_dev_poller *poller)
{
if (!poller->poll_interval)
poller->poll_interval = 500;
if (!poller->poll_interval_max)
poller->poll_interval_max = poller->poll_interval;
}
void input_dev_poller_start(struct input_dev_poller *poller)
{
/* Only start polling if polling is enabled */
if (poller->poll_interval > 0) {
poller->poll(poller->input);
input_dev_poller_queue_work(poller);
}
}
void input_dev_poller_stop(struct input_dev_poller *poller)
{
cancel_delayed_work_sync(&poller->work);
}
int input_setup_polling(struct input_dev *dev,
void (*poll_fn)(struct input_dev *dev))
{
struct input_dev_poller *poller;
poller = kzalloc(sizeof(*poller), GFP_KERNEL);
if (!poller) {
/*
* We want to show message even though kzalloc() may have
* printed backtrace as knowing what instance of input
* device we were dealing with is helpful.
*/
dev_err(dev->dev.parent ?: &dev->dev,
"%s: unable to allocate poller structure\n", __func__);
return -ENOMEM;
}
INIT_DELAYED_WORK(&poller->work, input_dev_poller_work);
poller->input = dev;
poller->poll = poll_fn;
dev->poller = poller;
return 0;
}
EXPORT_SYMBOL(input_setup_polling);
static bool input_dev_ensure_poller(struct input_dev *dev)
{
if (!dev->poller) {
dev_err(dev->dev.parent ?: &dev->dev,
"poller structure has not been set up\n");
return false;
}
return true;
}
void input_set_poll_interval(struct input_dev *dev, unsigned int interval)
{
if (input_dev_ensure_poller(dev))
dev->poller->poll_interval = interval;
}
EXPORT_SYMBOL(input_set_poll_interval);
void input_set_min_poll_interval(struct input_dev *dev, unsigned int interval)
{
if (input_dev_ensure_poller(dev))
dev->poller->poll_interval_min = interval;
}
EXPORT_SYMBOL(input_set_min_poll_interval);
void input_set_max_poll_interval(struct input_dev *dev, unsigned int interval)
{
if (input_dev_ensure_poller(dev))
dev->poller->poll_interval_max = interval;
}
EXPORT_SYMBOL(input_set_max_poll_interval);
/* SYSFS interface */
static ssize_t input_dev_get_poll_interval(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct input_dev *input = to_input_dev(dev);
return sprintf(buf, "%d\n", input->poller->poll_interval);
}
static ssize_t input_dev_set_poll_interval(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct input_dev *input = to_input_dev(dev);
struct input_dev_poller *poller = input->poller;
unsigned int interval;
int err;
err = kstrtouint(buf, 0, &interval);
if (err)
return err;
if (interval < poller->poll_interval_min)
return -EINVAL;
if (interval > poller->poll_interval_max)
return -EINVAL;
mutex_lock(&input->mutex);
poller->poll_interval = interval;
if (input->users) {
cancel_delayed_work_sync(&poller->work);
if (poller->poll_interval > 0)
input_dev_poller_queue_work(poller);
}
mutex_unlock(&input->mutex);
return count;
}
static DEVICE_ATTR(poll, 0644,
input_dev_get_poll_interval, input_dev_set_poll_interval);
static ssize_t input_dev_get_poll_max(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct input_dev *input = to_input_dev(dev);
return sprintf(buf, "%d\n", input->poller->poll_interval_max);
}
static DEVICE_ATTR(max, 0444, input_dev_get_poll_max, NULL);
static ssize_t input_dev_get_poll_min(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct input_dev *input = to_input_dev(dev);
return sprintf(buf, "%d\n", input->poller->poll_interval_min);
}
static DEVICE_ATTR(min, 0444, input_dev_get_poll_min, NULL);
static umode_t input_poller_attrs_visible(struct kobject *kobj,
struct attribute *attr, int n)
{
struct device *dev = kobj_to_dev(kobj);
struct input_dev *input = to_input_dev(dev);
return input->poller ? attr->mode : 0;
}
static struct attribute *input_poller_attrs[] = {
&dev_attr_poll.attr,
&dev_attr_max.attr,
&dev_attr_min.attr,
NULL
};
struct attribute_group input_poller_attribute_group = {
.is_visible = input_poller_attrs_visible,
.attrs = input_poller_attrs,
};

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@ -0,0 +1,18 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef _INPUT_POLLER_H
#define _INPUT_POLLER_H
/*
* Support for polling mode for input devices.
*/
#include <linux/sysfs.h>
struct input_dev_poller;
void input_dev_poller_finalize(struct input_dev_poller *poller);
void input_dev_poller_start(struct input_dev_poller *poller);
void input_dev_poller_stop(struct input_dev_poller *poller);
extern struct attribute_group input_poller_attribute_group;
#endif /* _INPUT_POLLER_H */

View File

@ -24,6 +24,7 @@
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include "input-compat.h"
#include "input-poller.h"
MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
MODULE_DESCRIPTION("Input core");
@ -603,20 +604,31 @@ int input_open_device(struct input_handle *handle)
handle->open++;
if (!dev->users++ && dev->open)
retval = dev->open(dev);
if (dev->users++) {
/*
* Device is already opened, so we can exit immediately and
* report success.
*/
goto out;
}
if (retval) {
dev->users--;
if (!--handle->open) {
if (dev->open) {
retval = dev->open(dev);
if (retval) {
dev->users--;
handle->open--;
/*
* Make sure we are not delivering any more events
* through this handle
*/
synchronize_rcu();
goto out;
}
}
if (dev->poller)
input_dev_poller_start(dev->poller);
out:
mutex_unlock(&dev->mutex);
return retval;
@ -655,8 +667,13 @@ void input_close_device(struct input_handle *handle)
__input_release_device(handle);
if (!--dev->users && dev->close)
dev->close(dev);
if (!--dev->users) {
if (dev->poller)
input_dev_poller_stop(dev->poller);
if (dev->close)
dev->close(dev);
}
if (!--handle->open) {
/*
@ -1502,6 +1519,7 @@ static const struct attribute_group *input_dev_attr_groups[] = {
&input_dev_attr_group,
&input_dev_id_attr_group,
&input_dev_caps_attr_group,
&input_poller_attribute_group,
NULL
};
@ -1511,6 +1529,7 @@ static void input_dev_release(struct device *device)
input_ff_destroy(dev);
input_mt_destroy_slots(dev);
kfree(dev->poller);
kfree(dev->absinfo);
kfree(dev->vals);
kfree(dev);
@ -2175,6 +2194,9 @@ int input_register_device(struct input_dev *dev)
if (!dev->setkeycode)
dev->setkeycode = input_default_setkeycode;
if (dev->poller)
input_dev_poller_finalize(dev->poller);
error = device_add(&dev->dev);
if (error)
goto err_free_vals;

View File

@ -21,6 +21,8 @@
#include <linux/timer.h>
#include <linux/mod_devicetable.h>
struct input_dev_poller;
/**
* struct input_value - input value representation
* @type: type of value (EV_KEY, EV_ABS, etc)
@ -71,6 +73,8 @@ enum input_clock_type {
* not sleep
* @ff: force feedback structure associated with the device if device
* supports force feedback effects
* @poller: poller structure associated with the device if device is
* set up to use polling mode
* @repeat_key: stores key code of the last key pressed; used to implement
* software autorepeat
* @timer: timer for software autorepeat
@ -156,6 +160,8 @@ struct input_dev {
struct ff_device *ff;
struct input_dev_poller *poller;
unsigned int repeat_key;
struct timer_list timer;
@ -372,6 +378,12 @@ void input_unregister_device(struct input_dev *);
void input_reset_device(struct input_dev *);
int input_setup_polling(struct input_dev *dev,
void (*poll_fn)(struct input_dev *dev));
void input_set_poll_interval(struct input_dev *dev, unsigned int interval);
void input_set_min_poll_interval(struct input_dev *dev, unsigned int interval);
void input_set_max_poll_interval(struct input_dev *dev, unsigned int interval);
int __must_check input_register_handler(struct input_handler *);
void input_unregister_handler(struct input_handler *);