1e95656eaSDmitry Torokhov // SPDX-License-Identifier: GPL-2.0-only 2e95656eaSDmitry Torokhov /* 3e95656eaSDmitry Torokhov * Support for polling mode for input devices. 4e95656eaSDmitry Torokhov */ 5e95656eaSDmitry Torokhov 6e95656eaSDmitry Torokhov #include <linux/device.h> 7e95656eaSDmitry Torokhov #include <linux/input.h> 8e95656eaSDmitry Torokhov #include <linux/jiffies.h> 9e95656eaSDmitry Torokhov #include <linux/mutex.h> 10e95656eaSDmitry Torokhov #include <linux/slab.h> 11e95656eaSDmitry Torokhov #include <linux/types.h> 12e95656eaSDmitry Torokhov #include <linux/workqueue.h> 13e95656eaSDmitry Torokhov #include "input-poller.h" 14e95656eaSDmitry Torokhov 15e95656eaSDmitry Torokhov struct input_dev_poller { 16e95656eaSDmitry Torokhov void (*poll)(struct input_dev *dev); 17e95656eaSDmitry Torokhov 18e95656eaSDmitry Torokhov unsigned int poll_interval; /* msec */ 19e95656eaSDmitry Torokhov unsigned int poll_interval_max; /* msec */ 20e95656eaSDmitry Torokhov unsigned int poll_interval_min; /* msec */ 21e95656eaSDmitry Torokhov 22e95656eaSDmitry Torokhov struct input_dev *input; 23e95656eaSDmitry Torokhov struct delayed_work work; 24e95656eaSDmitry Torokhov }; 25e95656eaSDmitry Torokhov 26e95656eaSDmitry Torokhov static void input_dev_poller_queue_work(struct input_dev_poller *poller) 27e95656eaSDmitry Torokhov { 28e95656eaSDmitry Torokhov unsigned long delay; 29e95656eaSDmitry Torokhov 30e95656eaSDmitry Torokhov delay = msecs_to_jiffies(poller->poll_interval); 31e95656eaSDmitry Torokhov if (delay >= HZ) 32e95656eaSDmitry Torokhov delay = round_jiffies_relative(delay); 33e95656eaSDmitry Torokhov 34e95656eaSDmitry Torokhov queue_delayed_work(system_freezable_wq, &poller->work, delay); 35e95656eaSDmitry Torokhov } 36e95656eaSDmitry Torokhov 37e95656eaSDmitry Torokhov static void input_dev_poller_work(struct work_struct *work) 38e95656eaSDmitry Torokhov { 39e95656eaSDmitry Torokhov struct input_dev_poller *poller = 40e95656eaSDmitry Torokhov container_of(work, struct input_dev_poller, work.work); 41e95656eaSDmitry Torokhov 42e95656eaSDmitry Torokhov poller->poll(poller->input); 43e95656eaSDmitry Torokhov input_dev_poller_queue_work(poller); 44e95656eaSDmitry Torokhov } 45e95656eaSDmitry Torokhov 46e95656eaSDmitry Torokhov void input_dev_poller_finalize(struct input_dev_poller *poller) 47e95656eaSDmitry Torokhov { 48e95656eaSDmitry Torokhov if (!poller->poll_interval) 49e95656eaSDmitry Torokhov poller->poll_interval = 500; 50e95656eaSDmitry Torokhov if (!poller->poll_interval_max) 51e95656eaSDmitry Torokhov poller->poll_interval_max = poller->poll_interval; 52e95656eaSDmitry Torokhov } 53e95656eaSDmitry Torokhov 54e95656eaSDmitry Torokhov void input_dev_poller_start(struct input_dev_poller *poller) 55e95656eaSDmitry Torokhov { 56e95656eaSDmitry Torokhov /* Only start polling if polling is enabled */ 57e95656eaSDmitry Torokhov if (poller->poll_interval > 0) { 58e95656eaSDmitry Torokhov poller->poll(poller->input); 59e95656eaSDmitry Torokhov input_dev_poller_queue_work(poller); 60e95656eaSDmitry Torokhov } 61e95656eaSDmitry Torokhov } 62e95656eaSDmitry Torokhov 63e95656eaSDmitry Torokhov void input_dev_poller_stop(struct input_dev_poller *poller) 64e95656eaSDmitry Torokhov { 65e95656eaSDmitry Torokhov cancel_delayed_work_sync(&poller->work); 66e95656eaSDmitry Torokhov } 67e95656eaSDmitry Torokhov 68e95656eaSDmitry Torokhov int input_setup_polling(struct input_dev *dev, 69e95656eaSDmitry Torokhov void (*poll_fn)(struct input_dev *dev)) 70e95656eaSDmitry Torokhov { 71e95656eaSDmitry Torokhov struct input_dev_poller *poller; 72e95656eaSDmitry Torokhov 73e95656eaSDmitry Torokhov poller = kzalloc(sizeof(*poller), GFP_KERNEL); 74e95656eaSDmitry Torokhov if (!poller) { 75e95656eaSDmitry Torokhov /* 76e95656eaSDmitry Torokhov * We want to show message even though kzalloc() may have 77e95656eaSDmitry Torokhov * printed backtrace as knowing what instance of input 78e95656eaSDmitry Torokhov * device we were dealing with is helpful. 79e95656eaSDmitry Torokhov */ 80e95656eaSDmitry Torokhov dev_err(dev->dev.parent ?: &dev->dev, 81e95656eaSDmitry Torokhov "%s: unable to allocate poller structure\n", __func__); 82e95656eaSDmitry Torokhov return -ENOMEM; 83e95656eaSDmitry Torokhov } 84e95656eaSDmitry Torokhov 85e95656eaSDmitry Torokhov INIT_DELAYED_WORK(&poller->work, input_dev_poller_work); 86e95656eaSDmitry Torokhov poller->input = dev; 87e95656eaSDmitry Torokhov poller->poll = poll_fn; 88e95656eaSDmitry Torokhov 89e95656eaSDmitry Torokhov dev->poller = poller; 90e95656eaSDmitry Torokhov return 0; 91e95656eaSDmitry Torokhov } 92e95656eaSDmitry Torokhov EXPORT_SYMBOL(input_setup_polling); 93e95656eaSDmitry Torokhov 94e95656eaSDmitry Torokhov static bool input_dev_ensure_poller(struct input_dev *dev) 95e95656eaSDmitry Torokhov { 96e95656eaSDmitry Torokhov if (!dev->poller) { 97e95656eaSDmitry Torokhov dev_err(dev->dev.parent ?: &dev->dev, 98e95656eaSDmitry Torokhov "poller structure has not been set up\n"); 99e95656eaSDmitry Torokhov return false; 100e95656eaSDmitry Torokhov } 101e95656eaSDmitry Torokhov 102e95656eaSDmitry Torokhov return true; 103e95656eaSDmitry Torokhov } 104e95656eaSDmitry Torokhov 105e95656eaSDmitry Torokhov void input_set_poll_interval(struct input_dev *dev, unsigned int interval) 106e95656eaSDmitry Torokhov { 107e95656eaSDmitry Torokhov if (input_dev_ensure_poller(dev)) 108e95656eaSDmitry Torokhov dev->poller->poll_interval = interval; 109e95656eaSDmitry Torokhov } 110e95656eaSDmitry Torokhov EXPORT_SYMBOL(input_set_poll_interval); 111e95656eaSDmitry Torokhov 112e95656eaSDmitry Torokhov void input_set_min_poll_interval(struct input_dev *dev, unsigned int interval) 113e95656eaSDmitry Torokhov { 114e95656eaSDmitry Torokhov if (input_dev_ensure_poller(dev)) 115e95656eaSDmitry Torokhov dev->poller->poll_interval_min = interval; 116e95656eaSDmitry Torokhov } 117e95656eaSDmitry Torokhov EXPORT_SYMBOL(input_set_min_poll_interval); 118e95656eaSDmitry Torokhov 119e95656eaSDmitry Torokhov void input_set_max_poll_interval(struct input_dev *dev, unsigned int interval) 120e95656eaSDmitry Torokhov { 121e95656eaSDmitry Torokhov if (input_dev_ensure_poller(dev)) 122e95656eaSDmitry Torokhov dev->poller->poll_interval_max = interval; 123e95656eaSDmitry Torokhov } 124e95656eaSDmitry Torokhov EXPORT_SYMBOL(input_set_max_poll_interval); 125e95656eaSDmitry Torokhov 126894616f7SDmitry Torokhov int input_get_poll_interval(struct input_dev *dev) 127894616f7SDmitry Torokhov { 128894616f7SDmitry Torokhov if (!dev->poller) 129894616f7SDmitry Torokhov return -EINVAL; 130894616f7SDmitry Torokhov 131894616f7SDmitry Torokhov return dev->poller->poll_interval; 132894616f7SDmitry Torokhov } 133894616f7SDmitry Torokhov EXPORT_SYMBOL(input_get_poll_interval); 134894616f7SDmitry Torokhov 135e95656eaSDmitry Torokhov /* SYSFS interface */ 136e95656eaSDmitry Torokhov 137e95656eaSDmitry Torokhov static ssize_t input_dev_get_poll_interval(struct device *dev, 138e95656eaSDmitry Torokhov struct device_attribute *attr, 139e95656eaSDmitry Torokhov char *buf) 140e95656eaSDmitry Torokhov { 141e95656eaSDmitry Torokhov struct input_dev *input = to_input_dev(dev); 142e95656eaSDmitry Torokhov 143e95656eaSDmitry Torokhov return sprintf(buf, "%d\n", input->poller->poll_interval); 144e95656eaSDmitry Torokhov } 145e95656eaSDmitry Torokhov 146e95656eaSDmitry Torokhov static ssize_t input_dev_set_poll_interval(struct device *dev, 147e95656eaSDmitry Torokhov struct device_attribute *attr, 148e95656eaSDmitry Torokhov const char *buf, size_t count) 149e95656eaSDmitry Torokhov { 150e95656eaSDmitry Torokhov struct input_dev *input = to_input_dev(dev); 151e95656eaSDmitry Torokhov struct input_dev_poller *poller = input->poller; 152e95656eaSDmitry Torokhov unsigned int interval; 153e95656eaSDmitry Torokhov int err; 154e95656eaSDmitry Torokhov 155e95656eaSDmitry Torokhov err = kstrtouint(buf, 0, &interval); 156e95656eaSDmitry Torokhov if (err) 157e95656eaSDmitry Torokhov return err; 158e95656eaSDmitry Torokhov 159e95656eaSDmitry Torokhov if (interval < poller->poll_interval_min) 160e95656eaSDmitry Torokhov return -EINVAL; 161e95656eaSDmitry Torokhov 162e95656eaSDmitry Torokhov if (interval > poller->poll_interval_max) 163e95656eaSDmitry Torokhov return -EINVAL; 164e95656eaSDmitry Torokhov 165e95656eaSDmitry Torokhov mutex_lock(&input->mutex); 166e95656eaSDmitry Torokhov 167e95656eaSDmitry Torokhov poller->poll_interval = interval; 168e95656eaSDmitry Torokhov 169e95656eaSDmitry Torokhov if (input->users) { 170e95656eaSDmitry Torokhov cancel_delayed_work_sync(&poller->work); 171e95656eaSDmitry Torokhov if (poller->poll_interval > 0) 172e95656eaSDmitry Torokhov input_dev_poller_queue_work(poller); 173e95656eaSDmitry Torokhov } 174e95656eaSDmitry Torokhov 175e95656eaSDmitry Torokhov mutex_unlock(&input->mutex); 176e95656eaSDmitry Torokhov 177e95656eaSDmitry Torokhov return count; 178e95656eaSDmitry Torokhov } 179e95656eaSDmitry Torokhov 180e95656eaSDmitry Torokhov static DEVICE_ATTR(poll, 0644, 181e95656eaSDmitry Torokhov input_dev_get_poll_interval, input_dev_set_poll_interval); 182e95656eaSDmitry Torokhov 183e95656eaSDmitry Torokhov static ssize_t input_dev_get_poll_max(struct device *dev, 184e95656eaSDmitry Torokhov struct device_attribute *attr, char *buf) 185e95656eaSDmitry Torokhov { 186e95656eaSDmitry Torokhov struct input_dev *input = to_input_dev(dev); 187e95656eaSDmitry Torokhov 188e95656eaSDmitry Torokhov return sprintf(buf, "%d\n", input->poller->poll_interval_max); 189e95656eaSDmitry Torokhov } 190e95656eaSDmitry Torokhov 191e95656eaSDmitry Torokhov static DEVICE_ATTR(max, 0444, input_dev_get_poll_max, NULL); 192e95656eaSDmitry Torokhov 193e95656eaSDmitry Torokhov static ssize_t input_dev_get_poll_min(struct device *dev, 194e95656eaSDmitry Torokhov struct device_attribute *attr, char *buf) 195e95656eaSDmitry Torokhov { 196e95656eaSDmitry Torokhov struct input_dev *input = to_input_dev(dev); 197e95656eaSDmitry Torokhov 198e95656eaSDmitry Torokhov return sprintf(buf, "%d\n", input->poller->poll_interval_min); 199e95656eaSDmitry Torokhov } 200e95656eaSDmitry Torokhov 201e95656eaSDmitry Torokhov static DEVICE_ATTR(min, 0444, input_dev_get_poll_min, NULL); 202e95656eaSDmitry Torokhov 203e95656eaSDmitry Torokhov static umode_t input_poller_attrs_visible(struct kobject *kobj, 204e95656eaSDmitry Torokhov struct attribute *attr, int n) 205e95656eaSDmitry Torokhov { 206e95656eaSDmitry Torokhov struct device *dev = kobj_to_dev(kobj); 207e95656eaSDmitry Torokhov struct input_dev *input = to_input_dev(dev); 208e95656eaSDmitry Torokhov 209e95656eaSDmitry Torokhov return input->poller ? attr->mode : 0; 210e95656eaSDmitry Torokhov } 211e95656eaSDmitry Torokhov 212e95656eaSDmitry Torokhov static struct attribute *input_poller_attrs[] = { 213e95656eaSDmitry Torokhov &dev_attr_poll.attr, 214e95656eaSDmitry Torokhov &dev_attr_max.attr, 215e95656eaSDmitry Torokhov &dev_attr_min.attr, 216e95656eaSDmitry Torokhov NULL 217e95656eaSDmitry Torokhov }; 218e95656eaSDmitry Torokhov 219e95656eaSDmitry Torokhov struct attribute_group input_poller_attribute_group = { 220e95656eaSDmitry Torokhov .is_visible = input_poller_attrs_visible, 221e95656eaSDmitry Torokhov .attrs = input_poller_attrs, 222e95656eaSDmitry Torokhov }; 223