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 MODULE_AUTHOR("Josh Triplett");
   8 MODULE_DESCRIPTION("ACPI Tiny Power Button Driver");
   9 MODULE_LICENSE("GPL");
  10
  11 static int power_signal __read_mostly = CONFIG_ACPI_TINY_POWER_BUTTON_SIGNAL;
  12 module_param(power_signal, int, 0644);
  13 MODULE_PARM_DESC(power_signal, "Power button sends this signal to init");
  14
  15 static 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 };
  20 MODULE_DEVICE_TABLE(acpi, tiny_power_button_device_ids);
  21
  22 static void acpi_tiny_power_button_notify(acpi_handle handle, u32 event, void *data)
  23 {
  24         kill_cad_pid(power_signal, 1);
  25 }
  26
  27 static void acpi_tiny_power_button_notify_run(void *not_used)
  28 {
  29         acpi_tiny_power_button_notify(NULL, ACPI_FIXED_HARDWARE_EVENT, NULL);
  30 }
  31
  32 static u32 acpi_tiny_power_button_event(void *not_used)
  33 {
  34         acpi_os_execute(OSL_NOTIFY_HANDLER, acpi_tiny_power_button_notify_run, NULL);
  35         return ACPI_INTERRUPT_HANDLED;
  36 }
  37
  38 static int acpi_tiny_power_button_add(struct acpi_device *device)
  39 {
  40         acpi_status status;
  41
  42         if (device->device_type == ACPI_BUS_TYPE_POWER_BUTTON) {
  43                 status = acpi_install_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
  44                                                           acpi_tiny_power_button_event,
  45                                                           NULL);
  46         } else {
  47                 status = acpi_install_notify_handler(device->handle,
  48                                                      ACPI_DEVICE_NOTIFY,
  49                                                      acpi_tiny_power_button_notify,
  50                                                      NULL);
  51         }
  52         if (ACPI_FAILURE(status))
  53                 return -ENODEV;
  54
  55         return 0;
  56 }
  57
  58 static void acpi_tiny_power_button_remove(struct acpi_device *device)
  59 {
  60         if (device->device_type == ACPI_BUS_TYPE_POWER_BUTTON) {
  61                 acpi_remove_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
  62                                                 acpi_tiny_power_button_event);
  63         } else {
  64                 acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
  65                                            acpi_tiny_power_button_notify);
  66         }
  67         acpi_os_wait_events_complete();
  68 }
  69
  70 static struct acpi_driver acpi_tiny_power_button_driver = {
  71         .name = "tiny-power-button",
  72         .class = "tiny-power-button",
  73         .ids = tiny_power_button_device_ids,
  74         .ops = {
  75                 .add = acpi_tiny_power_button_add,
  76                 .remove = acpi_tiny_power_button_remove,
  77         },
  78 };
  79
  80 module_acpi_driver(acpi_tiny_power_button_driver);