1 files changed, 165 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..1c79731562c2
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-input-events.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Input Events LED trigger
+ *
+ * Copyright (C) 2024 Hans de Goede <hansg@kernel.org>
+ */
+
+#include <linux/input.h>
+#include <linux/jiffies.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include "../leds.h"
+
+static unsigned long led_off_delay_ms = 5000;
+module_param(led_off_delay_ms, ulong, 0644);
+MODULE_PARM_DESC(led_off_delay_ms,
+	"Specify delay in ms for turning LEDs off after last input event");
+
+static struct input_events_data {
+	struct delayed_work work;
+	spinlock_t lock;
+	/* To avoid repeatedly setting the brightness while there are events */
+	bool led_on;
+	unsigned long led_off_time;
+} input_events_data;
+
+static struct led_trigger *input_events_led_trigger;
+
+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_trigger_event(input_events_led_trigger, LED_OFF);
+		data->led_on = false;
+	}
+
+	spin_unlock_irq(&data->lock);
+}
+
+static void input_events_event(struct input_handle *handle, unsigned int type,
+			       unsigned int code, int val)
+{
+	struct input_events_data *data = &input_events_data;
+	unsigned long led_off_delay = msecs_to_jiffies(led_off_delay_ms);
+	unsigned long flags;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	if (!data->led_on) {
+		led_trigger_event(input_events_led_trigger, LED_FULL);
+		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 = KBUILD_MODNAME;
+
+	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 struct input_handler input_events_handler = {
+	.name = KBUILD_MODNAME,
+	.event = input_events_event,
+	.connect = input_events_connect,
+	.disconnect = input_events_disconnect,
+	.id_table = input_events_ids,
+};
+
+static int __init input_events_init(void)
+{
+	int ret;
+
+	INIT_DELAYED_WORK(&input_events_data.work, led_input_events_work);
+	spin_lock_init(&input_events_data.lock);
+
+	led_trigger_register_simple("input-events", &input_events_led_trigger);
+
+	ret = input_register_handler(&input_events_handler);
+	if (ret) {
+		led_trigger_unregister_simple(input_events_led_trigger);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit input_events_exit(void)
+{
+	input_unregister_handler(&input_events_handler);
+	cancel_delayed_work_sync(&input_events_data.work);
+	led_trigger_unregister_simple(input_events_led_trigger);
+}
+
+module_init(input_events_init);
+module_exit(input_events_exit);
+
+MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
+MODULE_DESCRIPTION("Input Events LED trigger");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ledtrig:input-events");