diff options
Diffstat (limited to 'drivers/leds/trigger/ledtrig-input-events.c')
| -rw-r--r-- | drivers/leds/trigger/ledtrig-input-events.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/leds/trigger/ledtrig-input-events.c b/drivers/leds/trigger/ledtrig-input-events.c new file mode 100644 index 000000000000..1de0176799f9 --- /dev/null +++ b/drivers/leds/trigger/ledtrig-input-events.c @@ -0,0 +1,233 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Input Events LED trigger + * + * Copyright (C) 2024 Hans de Goede <hansg@kernel.org> + * Partially based on Atsushi Nemoto's ledtrig-heartbeat.c. + */ + +#include <linux/input.h> +#include <linux/jiffies.h> +#include <linux/leds.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/workqueue.h> +#include "../leds.h" + +#define DEFAULT_LED_OFF_DELAY_MS 5000 + +struct input_events_data { + struct input_handler handler; + struct delayed_work work; + spinlock_t lock; + struct led_classdev *led_cdev; + int led_cdev_saved_flags; + /* To avoid repeatedly setting the brightness while there are events */ + bool led_on; + unsigned long led_off_time; + unsigned long led_off_delay; +}; + +static void led_input_events_work(struct work_struct *work) +{ + struct input_events_data *data = + container_of(work, struct input_events_data, work.work); + + spin_lock_irq(&data->lock); + + /* + * This time_after_eq() check avoids a race where this work starts + * running before a new event pushed led_off_time back. + */ + if (time_after_eq(jiffies, data->led_off_time)) { + led_set_brightness_nosleep(data->led_cdev, LED_OFF); + data->led_on = false; + } + + spin_unlock_irq(&data->lock); +} + +static ssize_t delay_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct input_events_data *input_events_data = led_trigger_get_drvdata(dev); + + return sysfs_emit(buf, "%lu\n", input_events_data->led_off_delay); +} + +static ssize_t delay_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t size) +{ + struct input_events_data *input_events_data = led_trigger_get_drvdata(dev); + unsigned long delay; + int ret; + + ret = kstrtoul(buf, 0, &delay); + if (ret) + return ret; + + /* Clamp between 0.5 and 1000 seconds */ + delay = clamp_val(delay, 500UL, 1000000UL); + input_events_data->led_off_delay = msecs_to_jiffies(delay); + + return size; +} + +static DEVICE_ATTR_RW(delay); + +static struct attribute *input_events_led_attrs[] = { + &dev_attr_delay.attr, + NULL +}; +ATTRIBUTE_GROUPS(input_events_led); + +static void input_events_event(struct input_handle *handle, unsigned int type, + unsigned int code, int val) +{ + struct input_events_data *data = + container_of(handle->handler, struct input_events_data, handler); + unsigned long led_off_delay = READ_ONCE(data->led_off_delay); + struct led_classdev *led_cdev = data->led_cdev; + unsigned long flags; + + if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags)) + led_cdev->blink_brightness = led_cdev->new_blink_brightness; + + spin_lock_irqsave(&data->lock, flags); + + if (!data->led_on) { + led_set_brightness_nosleep(led_cdev, led_cdev->blink_brightness); + data->led_on = true; + } + data->led_off_time = jiffies + led_off_delay; + + spin_unlock_irqrestore(&data->lock, flags); + + mod_delayed_work(system_wq, &data->work, led_off_delay); +} + +static int input_events_connect(struct input_handler *handler, struct input_dev *dev, + const struct input_device_id *id) +{ + struct input_handle *handle; + int ret; + + handle = kzalloc(sizeof(*handle), GFP_KERNEL); + if (!handle) + return -ENOMEM; + + handle->dev = dev; + handle->handler = handler; + handle->name = "input-events"; + + ret = input_register_handle(handle); + if (ret) + goto err_free_handle; + + ret = input_open_device(handle); + if (ret) + goto err_unregister_handle; + + return 0; + +err_unregister_handle: + input_unregister_handle(handle); +err_free_handle: + kfree(handle); + return ret; +} + +static void input_events_disconnect(struct input_handle *handle) +{ + input_close_device(handle); + input_unregister_handle(handle); + kfree(handle); +} + +static const struct input_device_id input_events_ids[] = { + { + .flags = INPUT_DEVICE_ID_MATCH_EVBIT, + .evbit = { BIT_MASK(EV_KEY) }, + }, + { + .flags = INPUT_DEVICE_ID_MATCH_EVBIT, + .evbit = { BIT_MASK(EV_REL) }, + }, + { + .flags = INPUT_DEVICE_ID_MATCH_EVBIT, + .evbit = { BIT_MASK(EV_ABS) }, + }, + { } +}; + +static int input_events_activate(struct led_classdev *led_cdev) +{ + struct input_events_data *data; + int ret; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->handler.name = "input-events"; + data->handler.event = input_events_event; + data->handler.connect = input_events_connect; + data->handler.disconnect = input_events_disconnect; + data->handler.id_table = input_events_ids; + + INIT_DELAYED_WORK(&data->work, led_input_events_work); + spin_lock_init(&data->lock); + + data->led_cdev = led_cdev; + data->led_cdev_saved_flags = led_cdev->flags; + data->led_off_delay = msecs_to_jiffies(DEFAULT_LED_OFF_DELAY_MS); + + /* + * Use led_cdev->blink_brightness + LED_BLINK_SW flag so that sysfs + * brightness writes will change led_cdev->new_blink_brightness for + * configuring the on state brightness (like ledtrig-heartbeat). + */ + if (!led_cdev->blink_brightness) + led_cdev->blink_brightness = led_cdev->max_brightness; + + /* Start with LED off */ + led_set_brightness_nosleep(data->led_cdev, LED_OFF); + + ret = input_register_handler(&data->handler); + if (ret) { + kfree(data); + return ret; + } + + set_bit(LED_BLINK_SW, &led_cdev->work_flags); + + /* Turn LED off during suspend, original flags are restored on deactivate() */ + led_cdev->flags |= LED_CORE_SUSPENDRESUME; + + led_set_trigger_data(led_cdev, data); + return 0; +} + +static void input_events_deactivate(struct led_classdev *led_cdev) +{ + struct input_events_data *data = led_get_trigger_data(led_cdev); + + led_cdev->flags = data->led_cdev_saved_flags; + clear_bit(LED_BLINK_SW, &led_cdev->work_flags); + input_unregister_handler(&data->handler); + cancel_delayed_work_sync(&data->work); + kfree(data); +} + +static struct led_trigger input_events_led_trigger = { + .name = "input-events", + .activate = input_events_activate, + .deactivate = input_events_deactivate, + .groups = input_events_led_groups, +}; +module_led_trigger(input_events_led_trigger); + +MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>"); +MODULE_DESCRIPTION("Input Events LED trigger"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("ledtrig:input-events"); |