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drivers/input/input-poller.c
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e95656ea1 Input: add suppor... |
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// 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 ", __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 "); 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 ", 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 ", 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 ", 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, }; |