drivers/platform/x86/peaq-wmi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * PEAQ 2-in-1 WMI hotkey driver
   4  * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
   5  */
   6
   7 #include <linux/acpi.h>
   8 #include <linux/dmi.h>
   9 #include <linux/input.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12
  13 #define PEAQ_DOLBY_BUTTON_GUID          "ABBC0F6F-8EA1-11D1-00A0-C90629100000"
  14 #define PEAQ_DOLBY_BUTTON_METHOD_ID     5
  15 #define PEAQ_POLL_INTERVAL_MS           250
  16 #define PEAQ_POLL_IGNORE_MS             500
  17 #define PEAQ_POLL_MAX_MS                1000
  18
  19 MODULE_ALIAS("wmi:"PEAQ_DOLBY_BUTTON_GUID);
  20
  21 static struct input_dev *peaq_poll_dev;
  22
  23 /*
  24  * The Dolby button (yes really a Dolby button) causes an ACPI variable to get
  25  * set on both press and release. The WMI method checks and clears that flag.
  26  * So for a press + release we will get back One from the WMI method either once
  27  * (if polling after the release) or twice (polling between press and release).
  28  * We ignore events for 0.5s after the first event to avoid reporting 2 presses.
  29  */
  30 static void peaq_wmi_poll(struct input_dev *input_dev)
  31 {
  32         static unsigned long last_event_time;
  33         static bool had_events;
  34         union acpi_object obj;
  35         acpi_status status;
  36         u32 dummy = 0;
  37
  38         struct acpi_buffer input = { sizeof(dummy), &dummy };
  39         struct acpi_buffer output = { sizeof(obj), &obj };
  40
  41         status = wmi_evaluate_method(PEAQ_DOLBY_BUTTON_GUID, 0,
  42                                      PEAQ_DOLBY_BUTTON_METHOD_ID,
  43                                      &input, &output);
  44         if (ACPI_FAILURE(status))
  45                 return;
  46
  47         if (obj.type != ACPI_TYPE_INTEGER) {
  48                 dev_err(&input_dev->dev,
  49                         "Error WMBC did not return an integer\n");
  50                 return;
  51         }
  52
  53         if (!obj.integer.value)
  54                 return;
  55
  56         if (had_events && time_before(jiffies, last_event_time +
  57                                         msecs_to_jiffies(PEAQ_POLL_IGNORE_MS)))
  58                 return;
  59
  60         input_event(input_dev, EV_KEY, KEY_SOUND, 1);
  61         input_sync(input_dev);
  62         input_event(input_dev, EV_KEY, KEY_SOUND, 0);
  63         input_sync(input_dev);
  64
  65         last_event_time = jiffies;
  66         had_events = true;
  67 }
  68
  69 /* Some other devices (Shuttle XS35) use the same WMI GUID for other purposes */
  70 static const struct dmi_system_id peaq_dmi_table[] __initconst = {
  71         {
  72                 .matches = {
  73                         DMI_MATCH(DMI_SYS_VENDOR, "PEAQ"),
  74                         DMI_MATCH(DMI_PRODUCT_NAME, "PEAQ PMM C1010 MD99187"),
  75                 },
  76         },
  77         {}
  78 };
  79
  80 static int __init peaq_wmi_init(void)
  81 {
  82         int err;
  83
  84         /* WMI GUID is not unique, also check for a DMI match */
  85         if (!dmi_check_system(peaq_dmi_table))
  86                 return -ENODEV;
  87
  88         if (!wmi_has_guid(PEAQ_DOLBY_BUTTON_GUID))
  89                 return -ENODEV;
  90
  91         peaq_poll_dev = input_allocate_device();
  92         if (!peaq_poll_dev)
  93                 return -ENOMEM;
  94
  95         peaq_poll_dev->name = "PEAQ WMI hotkeys";
  96         peaq_poll_dev->phys = "wmi/input0";
  97         peaq_poll_dev->id.bustype = BUS_HOST;
  98         input_set_capability(peaq_poll_dev, EV_KEY, KEY_SOUND);
  99
 100         err = input_setup_polling(peaq_poll_dev, peaq_wmi_poll);
 101         if (err)
 102                 goto err_out;
 103
 104         input_set_poll_interval(peaq_poll_dev, PEAQ_POLL_INTERVAL_MS);
 105         input_set_max_poll_interval(peaq_poll_dev, PEAQ_POLL_MAX_MS);
 106
 107         err = input_register_device(peaq_poll_dev);
 108         if (err)
 109                 goto err_out;
 110
 111         return 0;
 112
 113 err_out:
 114         input_free_device(peaq_poll_dev);
 115         return err;
 116 }
 117
 118 static void __exit peaq_wmi_exit(void)
 119 {
 120         input_unregister_device(peaq_poll_dev);
 121 }
 122
 123 module_init(peaq_wmi_init);
 124 module_exit(peaq_wmi_exit);
 125
 126 MODULE_DESCRIPTION("PEAQ 2-in-1 WMI hotkey driver");
 127 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 128 MODULE_LICENSE("GPL");