drivers/platform/x86/peaq-wmi.c

   1 /*
   2  * PEAQ 2-in-1 WMI hotkey driver
   3  * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/acpi.h>
  11 #include <linux/dmi.h>
  12 #include <linux/input-polldev.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15
  16 #define PEAQ_DOLBY_BUTTON_GUID          "ABBC0F6F-8EA1-11D1-00A0-C90629100000"
  17 #define PEAQ_DOLBY_BUTTON_METHOD_ID     5
  18 #define PEAQ_POLL_INTERVAL_MS           250
  19 #define PEAQ_POLL_IGNORE_MS             500
  20 #define PEAQ_POLL_MAX_MS                1000
  21
  22 MODULE_ALIAS("wmi:"PEAQ_DOLBY_BUTTON_GUID);
  23
  24 static unsigned int peaq_ignore_events_counter;
  25 static struct input_polled_dev *peaq_poll_dev;
  26
  27 /*
  28  * The Dolby button (yes really a Dolby button) causes an ACPI variable to get
  29  * set on both press and release. The WMI method checks and clears that flag.
  30  * So for a press + release we will get back One from the WMI method either once
  31  * (if polling after the release) or twice (polling between press and release).
  32  * We ignore events for 0.5s after the first event to avoid reporting 2 presses.
  33  */
  34 static void peaq_wmi_poll(struct input_polled_dev *dev)
  35 {
  36         union acpi_object obj;
  37         acpi_status status;
  38         u32 dummy = 0;
  39
  40         struct acpi_buffer input = { sizeof(dummy), &dummy };
  41         struct acpi_buffer output = { sizeof(obj), &obj };
  42
  43         status = wmi_evaluate_method(PEAQ_DOLBY_BUTTON_GUID, 0,
  44                                      PEAQ_DOLBY_BUTTON_METHOD_ID,
  45                                      &input, &output);
  46         if (ACPI_FAILURE(status))
  47                 return;
  48
  49         if (obj.type != ACPI_TYPE_INTEGER) {
  50                 dev_err(&peaq_poll_dev->input->dev,
  51                         "Error WMBC did not return an integer\n");
  52                 return;
  53         }
  54
  55         if (peaq_ignore_events_counter && peaq_ignore_events_counter--)
  56                 return;
  57
  58         if (obj.integer.value) {
  59                 input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 1);
  60                 input_sync(peaq_poll_dev->input);
  61                 input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 0);
  62                 input_sync(peaq_poll_dev->input);
  63                 peaq_ignore_events_counter = max(1u,
  64                         PEAQ_POLL_IGNORE_MS / peaq_poll_dev->poll_interval);
  65         }
  66 }
  67
  68 /* Some other devices (Shuttle XS35) use the same WMI GUID for other purposes */
  69 static const struct dmi_system_id peaq_dmi_table[] __initconst = {
  70         {
  71                 .matches = {
  72                         DMI_MATCH(DMI_SYS_VENDOR, "PEAQ"),
  73                         DMI_MATCH(DMI_PRODUCT_NAME, "PEAQ PMM C1010 MD99187"),
  74                 },
  75         },
  76         {}
  77 };
  78
  79 static int __init peaq_wmi_init(void)
  80 {
  81         /* WMI GUID is not unique, also check for a DMI match */
  82         if (!dmi_check_system(peaq_dmi_table))
  83                 return -ENODEV;
  84
  85         if (!wmi_has_guid(PEAQ_DOLBY_BUTTON_GUID))
  86                 return -ENODEV;
  87
  88         peaq_poll_dev = input_allocate_polled_device();
  89         if (!peaq_poll_dev)
  90                 return -ENOMEM;
  91
  92         peaq_poll_dev->poll = peaq_wmi_poll;
  93         peaq_poll_dev->poll_interval = PEAQ_POLL_INTERVAL_MS;
  94         peaq_poll_dev->poll_interval_max = PEAQ_POLL_MAX_MS;
  95         peaq_poll_dev->input->name = "PEAQ WMI hotkeys";
  96         peaq_poll_dev->input->phys = "wmi/input0";
  97         peaq_poll_dev->input->id.bustype = BUS_HOST;
  98         input_set_capability(peaq_poll_dev->input, EV_KEY, KEY_SOUND);
  99
 100         return input_register_polled_device(peaq_poll_dev);
 101 }
 102
 103 static void __exit peaq_wmi_exit(void)
 104 {
 105         input_unregister_polled_device(peaq_poll_dev);
 106 }
 107
 108 module_init(peaq_wmi_init);
 109 module_exit(peaq_wmi_exit);
 110
 111 MODULE_DESCRIPTION("PEAQ 2-in-1 WMI hotkey driver");
 112 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 113 MODULE_LICENSE("GPL");