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
 19MODULE_ALIAS("wmi:"PEAQ_DOLBY_BUTTON_GUID);
 20
 21static 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 */
 30static 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 */
 70static 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
 80static 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
113err_out:
114	input_free_device(peaq_poll_dev);
115	return err;
116}
117
118static void __exit peaq_wmi_exit(void)
119{
120	input_unregister_device(peaq_poll_dev);
121}
122
123module_init(peaq_wmi_init);
124module_exit(peaq_wmi_exit);
125
126MODULE_DESCRIPTION("PEAQ 2-in-1 WMI hotkey driver");
127MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
128MODULE_LICENSE("GPL");