drivers/acpi/tiny-power-button.c

   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
   7 ACPI_MODULE_NAME("tiny-power-button");
   8 MODULE_AUTHOR("Josh Triplett");
   9 MODULE_DESCRIPTION("ACPI Tiny Power Button Driver");
  10 MODULE_LICENSE("GPL");
  11
  12 static int power_signal __read_mostly = CONFIG_ACPI_TINY_POWER_BUTTON_SIGNAL;
  13 module_param(power_signal, int, 0644);
  14 MODULE_PARM_DESC(power_signal, "Power button sends this signal to init");
  15
  16 static 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 };
  21 MODULE_DEVICE_TABLE(acpi, tiny_power_button_device_ids);
  22
  23 static int acpi_noop_add_remove(struct acpi_device *device)
  24 {
  25         return 0;
  26 }
  27
  28 static void acpi_tiny_power_button_notify(struct acpi_device *device, u32 event)
  29 {
  30         kill_cad_pid(power_signal, 1);
  31 }
  32
  33 static 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
  44 module_driver(acpi_tiny_power_button_driver,
  45                 acpi_bus_register_driver,
  46                 acpi_bus_unregister_driver);