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
 7MODULE_AUTHOR("Josh Triplett");
 8MODULE_DESCRIPTION("ACPI Tiny Power Button Driver");
 9MODULE_LICENSE("GPL");
10
11static int power_signal __read_mostly = CONFIG_ACPI_TINY_POWER_BUTTON_SIGNAL;
12module_param(power_signal, int, 0644);
13MODULE_PARM_DESC(power_signal, "Power button sends this signal to init");
14
15static const struct acpi_device_id tiny_power_button_device_ids[] = {
16	{ ACPI_BUTTON_HID_POWER, 0 },
17	{ ACPI_BUTTON_HID_POWERF, 0 },
18	{ "", 0 },
19};
20MODULE_DEVICE_TABLE(acpi, tiny_power_button_device_ids);
21
22static int acpi_noop_add_remove(struct acpi_device *device)
23{
24	return 0;
25}
26
27static void acpi_tiny_power_button_notify(struct acpi_device *device, u32 event)
28{
29	kill_cad_pid(power_signal, 1);
30}
31
32static struct acpi_driver acpi_tiny_power_button_driver = {
33	.name = "tiny-power-button",
34	.class = "tiny-power-button",
35	.ids = tiny_power_button_device_ids,
36	.ops = {
37		.add = acpi_noop_add_remove,
38		.remove = acpi_noop_add_remove,
39		.notify = acpi_tiny_power_button_notify,
40	},
41};
42
43module_acpi_driver(acpi_tiny_power_button_driver);