1// SPDX-License-Identifier: GPL-2.0-or-later
 2#include <linux/module.h>
 3#include <linux/sched/signal.h>
 4#include <linux/acpi.h>
 5#include <acpi/button.h>
 6
 7ACPI_MODULE_NAME("tiny-power-button");
 8MODULE_AUTHOR("Josh Triplett");
 9MODULE_DESCRIPTION("ACPI Tiny Power Button Driver");
10MODULE_LICENSE("GPL");
11
12static int power_signal __read_mostly = CONFIG_ACPI_TINY_POWER_BUTTON_SIGNAL;
13module_param(power_signal, int, 0644);
14MODULE_PARM_DESC(power_signal, "Power button sends this signal to init");
15
16static const struct acpi_device_id tiny_power_button_device_ids[] = {
17	{ ACPI_BUTTON_HID_POWER, 0 },
18	{ ACPI_BUTTON_HID_POWERF, 0 },
19	{ "", 0 },
20};
21MODULE_DEVICE_TABLE(acpi, tiny_power_button_device_ids);
22
23static int acpi_noop_add_remove(struct acpi_device *device)
24{
25	return 0;
26}
27
28static void acpi_tiny_power_button_notify(struct acpi_device *device, u32 event)
29{
30	kill_cad_pid(power_signal, 1);
31}
32
33static struct acpi_driver acpi_tiny_power_button_driver = {
34	.name = "tiny-power-button",
35	.class = "tiny-power-button",
36	.ids = tiny_power_button_device_ids,
37	.ops = {
38		.add = acpi_noop_add_remove,
39		.remove = acpi_noop_add_remove,
40		.notify = acpi_tiny_power_button_notify,
41	},
42};
43
44module_driver(acpi_tiny_power_button_driver,
45		acpi_bus_register_driver,
46		acpi_bus_unregister_driver);