diff options
Diffstat (limited to 'drivers/input/input-poller.c')
| -rw-r--r-- | drivers/input/input-poller.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/drivers/input/input-poller.c b/drivers/input/input-poller.c new file mode 100644 index 000000000000..1b3d28964bb2 --- /dev/null +++ b/drivers/input/input-poller.c @@ -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, +}; |